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diff --git a/deps/jemalloc/doc/jemalloc.xml.in b/deps/jemalloc/doc/jemalloc.xml.in new file mode 100644 index 0000000..e28e8f3 --- /dev/null +++ b/deps/jemalloc/doc/jemalloc.xml.in @@ -0,0 +1,3763 @@ +<?xml version='1.0' encoding='UTF-8'?> +<?xml-stylesheet type="text/xsl" + href="http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" + "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [ +]> + +<refentry> + <refentryinfo> + <title>User Manual</title> + <productname>jemalloc</productname> + <releaseinfo role="version">@jemalloc_version@</releaseinfo> + <authorgroup> + <author> + <firstname>Jason</firstname> + <surname>Evans</surname> + <personblurb>Author</personblurb> + </author> + </authorgroup> + </refentryinfo> + <refmeta> + <refentrytitle>JEMALLOC</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + <refnamediv> + <refdescriptor>jemalloc</refdescriptor> + <refname>jemalloc</refname> + <!-- Each refname causes a man page file to be created. Only if this were + the system malloc(3) implementation would these files be appropriate. + <refname>malloc</refname> + <refname>calloc</refname> + <refname>posix_memalign</refname> + <refname>aligned_alloc</refname> + <refname>realloc</refname> + <refname>free</refname> + <refname>mallocx</refname> + <refname>rallocx</refname> + <refname>xallocx</refname> + <refname>sallocx</refname> + <refname>dallocx</refname> + <refname>sdallocx</refname> + <refname>nallocx</refname> + <refname>mallctl</refname> + <refname>mallctlnametomib</refname> + <refname>mallctlbymib</refname> + <refname>malloc_stats_print</refname> + <refname>malloc_usable_size</refname> + --> + <refpurpose>general purpose memory allocation functions</refpurpose> + </refnamediv> + <refsect1 id="library"> + <title>LIBRARY</title> + <para>This manual describes jemalloc @jemalloc_version@. More information + can be found at the <ulink + url="http://jemalloc.net/">jemalloc website</ulink>.</para> + </refsect1> + <refsynopsisdiv> + <title>SYNOPSIS</title> + <funcsynopsis> + <funcsynopsisinfo>#include <<filename class="headerfile">jemalloc/jemalloc.h</filename>></funcsynopsisinfo> + <refsect2> + <title>Standard API</title> + <funcprototype> + <funcdef>void *<function>malloc</function></funcdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void *<function>calloc</function></funcdef> + <paramdef>size_t <parameter>number</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>int <function>posix_memalign</function></funcdef> + <paramdef>void **<parameter>ptr</parameter></paramdef> + <paramdef>size_t <parameter>alignment</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void *<function>aligned_alloc</function></funcdef> + <paramdef>size_t <parameter>alignment</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void *<function>realloc</function></funcdef> + <paramdef>void *<parameter>ptr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void <function>free</function></funcdef> + <paramdef>void *<parameter>ptr</parameter></paramdef> + </funcprototype> + </refsect2> + <refsect2> + <title>Non-standard API</title> + <funcprototype> + <funcdef>void *<function>mallocx</function></funcdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void *<function>rallocx</function></funcdef> + <paramdef>void *<parameter>ptr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>size_t <function>xallocx</function></funcdef> + <paramdef>void *<parameter>ptr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>size_t <parameter>extra</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>size_t <function>sallocx</function></funcdef> + <paramdef>void *<parameter>ptr</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void <function>dallocx</function></funcdef> + <paramdef>void *<parameter>ptr</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void <function>sdallocx</function></funcdef> + <paramdef>void *<parameter>ptr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>size_t <function>nallocx</function></funcdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>int <function>mallctl</function></funcdef> + <paramdef>const char *<parameter>name</parameter></paramdef> + <paramdef>void *<parameter>oldp</parameter></paramdef> + <paramdef>size_t *<parameter>oldlenp</parameter></paramdef> + <paramdef>void *<parameter>newp</parameter></paramdef> + <paramdef>size_t <parameter>newlen</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>int <function>mallctlnametomib</function></funcdef> + <paramdef>const char *<parameter>name</parameter></paramdef> + <paramdef>size_t *<parameter>mibp</parameter></paramdef> + <paramdef>size_t *<parameter>miblenp</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>int <function>mallctlbymib</function></funcdef> + <paramdef>const size_t *<parameter>mib</parameter></paramdef> + <paramdef>size_t <parameter>miblen</parameter></paramdef> + <paramdef>void *<parameter>oldp</parameter></paramdef> + <paramdef>size_t *<parameter>oldlenp</parameter></paramdef> + <paramdef>void *<parameter>newp</parameter></paramdef> + <paramdef>size_t <parameter>newlen</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void <function>malloc_stats_print</function></funcdef> + <paramdef>void <parameter>(*write_cb)</parameter> + <funcparams>void *, const char *</funcparams> + </paramdef> + <paramdef>void *<parameter>cbopaque</parameter></paramdef> + <paramdef>const char *<parameter>opts</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>size_t <function>malloc_usable_size</function></funcdef> + <paramdef>const void *<parameter>ptr</parameter></paramdef> + </funcprototype> + <funcprototype> + <funcdef>void <function>(*malloc_message)</function></funcdef> + <paramdef>void *<parameter>cbopaque</parameter></paramdef> + <paramdef>const char *<parameter>s</parameter></paramdef> + </funcprototype> + <para><type>const char *</type><varname>malloc_conf</varname>;</para> + </refsect2> + </funcsynopsis> + </refsynopsisdiv> + <refsect1 id="description"> + <title>DESCRIPTION</title> + <refsect2> + <title>Standard API</title> + + <para>The <function>malloc()</function> function allocates + <parameter>size</parameter> bytes of uninitialized memory. The allocated + space is suitably aligned (after possible pointer coercion) for storage + of any type of object.</para> + + <para>The <function>calloc()</function> function allocates + space for <parameter>number</parameter> objects, each + <parameter>size</parameter> bytes in length. The result is identical to + calling <function>malloc()</function> with an argument of + <parameter>number</parameter> * <parameter>size</parameter>, with the + exception that the allocated memory is explicitly initialized to zero + bytes.</para> + + <para>The <function>posix_memalign()</function> function + allocates <parameter>size</parameter> bytes of memory such that the + allocation's base address is a multiple of + <parameter>alignment</parameter>, and returns the allocation in the value + pointed to by <parameter>ptr</parameter>. The requested + <parameter>alignment</parameter> must be a power of 2 at least as large as + <code language="C">sizeof(<type>void *</type>)</code>.</para> + + <para>The <function>aligned_alloc()</function> function + allocates <parameter>size</parameter> bytes of memory such that the + allocation's base address is a multiple of + <parameter>alignment</parameter>. The requested + <parameter>alignment</parameter> must be a power of 2. Behavior is + undefined if <parameter>size</parameter> is not an integral multiple of + <parameter>alignment</parameter>.</para> + + <para>The <function>realloc()</function> function changes the + size of the previously allocated memory referenced by + <parameter>ptr</parameter> to <parameter>size</parameter> bytes. The + contents of the memory are unchanged up to the lesser of the new and old + sizes. If the new size is larger, the contents of the newly allocated + portion of the memory are undefined. Upon success, the memory referenced + by <parameter>ptr</parameter> is freed and a pointer to the newly + allocated memory is returned. Note that + <function>realloc()</function> may move the memory allocation, + resulting in a different return value than <parameter>ptr</parameter>. + If <parameter>ptr</parameter> is <constant>NULL</constant>, the + <function>realloc()</function> function behaves identically to + <function>malloc()</function> for the specified size.</para> + + <para>The <function>free()</function> function causes the + allocated memory referenced by <parameter>ptr</parameter> to be made + available for future allocations. If <parameter>ptr</parameter> is + <constant>NULL</constant>, no action occurs.</para> + </refsect2> + <refsect2> + <title>Non-standard API</title> + <para>The <function>mallocx()</function>, + <function>rallocx()</function>, + <function>xallocx()</function>, + <function>sallocx()</function>, + <function>dallocx()</function>, + <function>sdallocx()</function>, and + <function>nallocx()</function> functions all have a + <parameter>flags</parameter> argument that can be used to specify + options. The functions only check the options that are contextually + relevant. Use bitwise or (<code language="C">|</code>) operations to + specify one or more of the following: + <variablelist> + <varlistentry id="MALLOCX_LG_ALIGN"> + <term><constant>MALLOCX_LG_ALIGN(<parameter>la</parameter>) + </constant></term> + + <listitem><para>Align the memory allocation to start at an address + that is a multiple of <code language="C">(1 << + <parameter>la</parameter>)</code>. This macro does not validate + that <parameter>la</parameter> is within the valid + range.</para></listitem> + </varlistentry> + <varlistentry id="MALLOCX_ALIGN"> + <term><constant>MALLOCX_ALIGN(<parameter>a</parameter>) + </constant></term> + + <listitem><para>Align the memory allocation to start at an address + that is a multiple of <parameter>a</parameter>, where + <parameter>a</parameter> is a power of two. This macro does not + validate that <parameter>a</parameter> is a power of 2. + </para></listitem> + </varlistentry> + <varlistentry id="MALLOCX_ZERO"> + <term><constant>MALLOCX_ZERO</constant></term> + + <listitem><para>Initialize newly allocated memory to contain zero + bytes. In the growing reallocation case, the real size prior to + reallocation defines the boundary between untouched bytes and those + that are initialized to contain zero bytes. If this macro is + absent, newly allocated memory is uninitialized.</para></listitem> + </varlistentry> + <varlistentry id="MALLOCX_TCACHE"> + <term><constant>MALLOCX_TCACHE(<parameter>tc</parameter>) + </constant></term> + + <listitem><para>Use the thread-specific cache (tcache) specified by + the identifier <parameter>tc</parameter>, which must have been + acquired via the <link + linkend="tcache.create"><mallctl>tcache.create</mallctl></link> + mallctl. This macro does not validate that + <parameter>tc</parameter> specifies a valid + identifier.</para></listitem> + </varlistentry> + <varlistentry id="MALLOC_TCACHE_NONE"> + <term><constant>MALLOCX_TCACHE_NONE</constant></term> + + <listitem><para>Do not use a thread-specific cache (tcache). Unless + <constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant> or + <constant>MALLOCX_TCACHE_NONE</constant> is specified, an + automatically managed tcache will be used under many circumstances. + This macro cannot be used in the same <parameter>flags</parameter> + argument as + <constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant>.</para></listitem> + </varlistentry> + <varlistentry id="MALLOCX_ARENA"> + <term><constant>MALLOCX_ARENA(<parameter>a</parameter>) + </constant></term> + + <listitem><para>Use the arena specified by the index + <parameter>a</parameter>. This macro has no effect for regions that + were allocated via an arena other than the one specified. This + macro does not validate that <parameter>a</parameter> specifies an + arena index in the valid range.</para></listitem> + </varlistentry> + </variablelist> + </para> + + <para>The <function>mallocx()</function> function allocates at + least <parameter>size</parameter> bytes of memory, and returns a pointer + to the base address of the allocation. Behavior is undefined if + <parameter>size</parameter> is <constant>0</constant>.</para> + + <para>The <function>rallocx()</function> function resizes the + allocation at <parameter>ptr</parameter> to be at least + <parameter>size</parameter> bytes, and returns a pointer to the base + address of the resulting allocation, which may or may not have moved from + its original location. Behavior is undefined if + <parameter>size</parameter> is <constant>0</constant>.</para> + + <para>The <function>xallocx()</function> function resizes the + allocation at <parameter>ptr</parameter> in place to be at least + <parameter>size</parameter> bytes, and returns the real size of the + allocation. If <parameter>extra</parameter> is non-zero, an attempt is + made to resize the allocation to be at least <code + language="C">(<parameter>size</parameter> + + <parameter>extra</parameter>)</code> bytes, though inability to allocate + the extra byte(s) will not by itself result in failure to resize. + Behavior is undefined if <parameter>size</parameter> is + <constant>0</constant>, or if <code + language="C">(<parameter>size</parameter> + <parameter>extra</parameter> + > <constant>SIZE_T_MAX</constant>)</code>.</para> + + <para>The <function>sallocx()</function> function returns the + real size of the allocation at <parameter>ptr</parameter>.</para> + + <para>The <function>dallocx()</function> function causes the + memory referenced by <parameter>ptr</parameter> to be made available for + future allocations.</para> + + <para>The <function>sdallocx()</function> function is an + extension of <function>dallocx()</function> with a + <parameter>size</parameter> parameter to allow the caller to pass in the + allocation size as an optimization. The minimum valid input size is the + original requested size of the allocation, and the maximum valid input + size is the corresponding value returned by + <function>nallocx()</function> or + <function>sallocx()</function>.</para> + + <para>The <function>nallocx()</function> function allocates no + memory, but it performs the same size computation as the + <function>mallocx()</function> function, and returns the real + size of the allocation that would result from the equivalent + <function>mallocx()</function> function call, or + <constant>0</constant> if the inputs exceed the maximum supported size + class and/or alignment. Behavior is undefined if + <parameter>size</parameter> is <constant>0</constant>.</para> + + <para>The <function>mallctl()</function> function provides a + general interface for introspecting the memory allocator, as well as + setting modifiable parameters and triggering actions. The + period-separated <parameter>name</parameter> argument specifies a + location in a tree-structured namespace; see the <xref + linkend="mallctl_namespace" xrefstyle="template:%t"/> section for + documentation on the tree contents. To read a value, pass a pointer via + <parameter>oldp</parameter> to adequate space to contain the value, and a + pointer to its length via <parameter>oldlenp</parameter>; otherwise pass + <constant>NULL</constant> and <constant>NULL</constant>. Similarly, to + write a value, pass a pointer to the value via + <parameter>newp</parameter>, and its length via + <parameter>newlen</parameter>; otherwise pass <constant>NULL</constant> + and <constant>0</constant>.</para> + + <para>The <function>mallctlnametomib()</function> function + provides a way to avoid repeated name lookups for applications that + repeatedly query the same portion of the namespace, by translating a name + to a <quote>Management Information Base</quote> (MIB) that can be passed + repeatedly to <function>mallctlbymib()</function>. Upon + successful return from <function>mallctlnametomib()</function>, + <parameter>mibp</parameter> contains an array of + <parameter>*miblenp</parameter> integers, where + <parameter>*miblenp</parameter> is the lesser of the number of components + in <parameter>name</parameter> and the input value of + <parameter>*miblenp</parameter>. Thus it is possible to pass a + <parameter>*miblenp</parameter> that is smaller than the number of + period-separated name components, which results in a partial MIB that can + be used as the basis for constructing a complete MIB. For name + components that are integers (e.g. the 2 in + <link + linkend="arenas.bin.i.size"><mallctl>arenas.bin.2.size</mallctl></link>), + the corresponding MIB component will always be that integer. Therefore, + it is legitimate to construct code like the following: <programlisting + language="C"><![CDATA[ +unsigned nbins, i; +size_t mib[4]; +size_t len, miblen; + +len = sizeof(nbins); +mallctl("arenas.nbins", &nbins, &len, NULL, 0); + +miblen = 4; +mallctlnametomib("arenas.bin.0.size", mib, &miblen); +for (i = 0; i < nbins; i++) { + size_t bin_size; + + mib[2] = i; + len = sizeof(bin_size); + mallctlbymib(mib, miblen, (void *)&bin_size, &len, NULL, 0); + /* Do something with bin_size... */ +}]]></programlisting></para> + + <varlistentry id="malloc_stats_print_opts"> + </varlistentry> + <para>The <function>malloc_stats_print()</function> function writes + summary statistics via the <parameter>write_cb</parameter> callback + function pointer and <parameter>cbopaque</parameter> data passed to + <parameter>write_cb</parameter>, or <function>malloc_message()</function> + if <parameter>write_cb</parameter> is <constant>NULL</constant>. The + statistics are presented in human-readable form unless <quote>J</quote> is + specified as a character within the <parameter>opts</parameter> string, in + which case the statistics are presented in <ulink + url="http://www.json.org/">JSON format</ulink>. This function can be + called repeatedly. General information that never changes during + execution can be omitted by specifying <quote>g</quote> as a character + within the <parameter>opts</parameter> string. Note that + <function>malloc_stats_print()</function> uses the + <function>mallctl*()</function> functions internally, so inconsistent + statistics can be reported if multiple threads use these functions + simultaneously. If <option>--enable-stats</option> is specified during + configuration, <quote>m</quote>, <quote>d</quote>, and <quote>a</quote> + can be specified to omit merged arena, destroyed merged arena, and per + arena statistics, respectively; <quote>b</quote> and <quote>l</quote> can + be specified to omit per size class statistics for bins and large objects, + respectively; <quote>x</quote> can be specified to omit all mutex + statistics; <quote>e</quote> can be used to omit extent statistics. + Unrecognized characters are silently ignored. Note that thread caching + may prevent some statistics from being completely up to date, since extra + locking would be required to merge counters that track thread cache + operations.</para> + + <para>The <function>malloc_usable_size()</function> function + returns the usable size of the allocation pointed to by + <parameter>ptr</parameter>. The return value may be larger than the size + that was requested during allocation. The + <function>malloc_usable_size()</function> function is not a + mechanism for in-place <function>realloc()</function>; rather + it is provided solely as a tool for introspection purposes. Any + discrepancy between the requested allocation size and the size reported + by <function>malloc_usable_size()</function> should not be + depended on, since such behavior is entirely implementation-dependent. + </para> + </refsect2> + </refsect1> + <refsect1 id="tuning"> + <title>TUNING</title> + <para>Once, when the first call is made to one of the memory allocation + routines, the allocator initializes its internals based in part on various + options that can be specified at compile- or run-time.</para> + + <para>The string specified via <option>--with-malloc-conf</option>, the + string pointed to by the global variable <varname>malloc_conf</varname>, the + <quote>name</quote> of the file referenced by the symbolic link named + <filename class="symlink">/etc/malloc.conf</filename>, and the value of the + environment variable <envar>MALLOC_CONF</envar>, will be interpreted, in + that order, from left to right as options. Note that + <varname>malloc_conf</varname> may be read before + <function>main()</function> is entered, so the declaration of + <varname>malloc_conf</varname> should specify an initializer that contains + the final value to be read by jemalloc. <option>--with-malloc-conf</option> + and <varname>malloc_conf</varname> are compile-time mechanisms, whereas + <filename class="symlink">/etc/malloc.conf</filename> and + <envar>MALLOC_CONF</envar> can be safely set any time prior to program + invocation.</para> + + <para>An options string is a comma-separated list of option:value pairs. + There is one key corresponding to each <link + linkend="opt.abort"><mallctl>opt.*</mallctl></link> mallctl (see the <xref + linkend="mallctl_namespace" xrefstyle="template:%t"/> section for options + documentation). For example, <literal>abort:true,narenas:1</literal> sets + the <link linkend="opt.abort"><mallctl>opt.abort</mallctl></link> and <link + linkend="opt.narenas"><mallctl>opt.narenas</mallctl></link> options. Some + options have boolean values (true/false), others have integer values (base + 8, 10, or 16, depending on prefix), and yet others have raw string + values.</para> + </refsect1> + <refsect1 id="implementation_notes"> + <title>IMPLEMENTATION NOTES</title> + <para>Traditionally, allocators have used + <citerefentry><refentrytitle>sbrk</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> to obtain memory, which is + suboptimal for several reasons, including race conditions, increased + fragmentation, and artificial limitations on maximum usable memory. If + <citerefentry><refentrytitle>sbrk</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> is supported by the operating + system, this allocator uses both + <citerefentry><refentrytitle>mmap</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> and + <citerefentry><refentrytitle>sbrk</refentrytitle> + <manvolnum>2</manvolnum></citerefentry>, in that order of preference; + otherwise only <citerefentry><refentrytitle>mmap</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> is used.</para> + + <para>This allocator uses multiple arenas in order to reduce lock + contention for threaded programs on multi-processor systems. This works + well with regard to threading scalability, but incurs some costs. There is + a small fixed per-arena overhead, and additionally, arenas manage memory + completely independently of each other, which means a small fixed increase + in overall memory fragmentation. These overheads are not generally an + issue, given the number of arenas normally used. Note that using + substantially more arenas than the default is not likely to improve + performance, mainly due to reduced cache performance. However, it may make + sense to reduce the number of arenas if an application does not make much + use of the allocation functions.</para> + + <para>In addition to multiple arenas, this allocator supports + thread-specific caching, in order to make it possible to completely avoid + synchronization for most allocation requests. Such caching allows very fast + allocation in the common case, but it increases memory usage and + fragmentation, since a bounded number of objects can remain allocated in + each thread cache.</para> + + <para>Memory is conceptually broken into extents. Extents are always + aligned to multiples of the page size. This alignment makes it possible to + find metadata for user objects quickly. User objects are broken into two + categories according to size: small and large. Contiguous small objects + comprise a slab, which resides within a single extent, whereas large objects + each have their own extents backing them.</para> + + <para>Small objects are managed in groups by slabs. Each slab maintains + a bitmap to track which regions are in use. Allocation requests that are no + more than half the quantum (8 or 16, depending on architecture) are rounded + up to the nearest power of two that is at least <code + language="C">sizeof(<type>double</type>)</code>. All other object size + classes are multiples of the quantum, spaced such that there are four size + classes for each doubling in size, which limits internal fragmentation to + approximately 20% for all but the smallest size classes. Small size classes + are smaller than four times the page size, and large size classes extend + from four times the page size up to the largest size class that does not + exceed <constant>PTRDIFF_MAX</constant>.</para> + + <para>Allocations are packed tightly together, which can be an issue for + multi-threaded applications. If you need to assure that allocations do not + suffer from cacheline sharing, round your allocation requests up to the + nearest multiple of the cacheline size, or specify cacheline alignment when + allocating.</para> + + <para>The <function>realloc()</function>, + <function>rallocx()</function>, and + <function>xallocx()</function> functions may resize allocations + without moving them under limited circumstances. Unlike the + <function>*allocx()</function> API, the standard API does not + officially round up the usable size of an allocation to the nearest size + class, so technically it is necessary to call + <function>realloc()</function> to grow e.g. a 9-byte allocation to + 16 bytes, or shrink a 16-byte allocation to 9 bytes. Growth and shrinkage + trivially succeeds in place as long as the pre-size and post-size both round + up to the same size class. No other API guarantees are made regarding + in-place resizing, but the current implementation also tries to resize large + allocations in place, as long as the pre-size and post-size are both large. + For shrinkage to succeed, the extent allocator must support splitting (see + <link + linkend="arena.i.extent_hooks"><mallctl>arena.<i>.extent_hooks</mallctl></link>). + Growth only succeeds if the trailing memory is currently available, and the + extent allocator supports merging.</para> + + <para>Assuming 4 KiB pages and a 16-byte quantum on a 64-bit system, the + size classes in each category are as shown in <xref linkend="size_classes" + xrefstyle="template:Table %n"/>.</para> + + <table xml:id="size_classes" frame="all"> + <title>Size classes</title> + <tgroup cols="3" colsep="1" rowsep="1"> + <colspec colname="c1" align="left"/> + <colspec colname="c2" align="right"/> + <colspec colname="c3" align="left"/> + <thead> + <row> + <entry>Category</entry> + <entry>Spacing</entry> + <entry>Size</entry> + </row> + </thead> + <tbody> + <row> + <entry morerows="8">Small</entry> + <entry>lg</entry> + <entry>[8]</entry> + </row> + <row> + <entry>16</entry> + <entry>[16, 32, 48, 64, 80, 96, 112, 128]</entry> + </row> + <row> + <entry>32</entry> + <entry>[160, 192, 224, 256]</entry> + </row> + <row> + <entry>64</entry> + <entry>[320, 384, 448, 512]</entry> + </row> + <row> + <entry>128</entry> + <entry>[640, 768, 896, 1024]</entry> + </row> + <row> + <entry>256</entry> + <entry>[1280, 1536, 1792, 2048]</entry> + </row> + <row> + <entry>512</entry> + <entry>[2560, 3072, 3584, 4096]</entry> + </row> + <row> + <entry>1 KiB</entry> + <entry>[5 KiB, 6 KiB, 7 KiB, 8 KiB]</entry> + </row> + <row> + <entry>2 KiB</entry> + <entry>[10 KiB, 12 KiB, 14 KiB]</entry> + </row> + <row> + <entry morerows="15">Large</entry> + <entry>2 KiB</entry> + <entry>[16 KiB]</entry> + </row> + <row> + <entry>4 KiB</entry> + <entry>[20 KiB, 24 KiB, 28 KiB, 32 KiB]</entry> + </row> + <row> + <entry>8 KiB</entry> + <entry>[40 KiB, 48 KiB, 56 KiB, 64 KiB]</entry> + </row> + <row> + <entry>16 KiB</entry> + <entry>[80 KiB, 96 KiB, 112 KiB, 128 KiB]</entry> + </row> + <row> + <entry>32 KiB</entry> + <entry>[160 KiB, 192 KiB, 224 KiB, 256 KiB]</entry> + </row> + <row> + <entry>64 KiB</entry> + <entry>[320 KiB, 384 KiB, 448 KiB, 512 KiB]</entry> + </row> + <row> + <entry>128 KiB</entry> + <entry>[640 KiB, 768 KiB, 896 KiB, 1 MiB]</entry> + </row> + <row> + <entry>256 KiB</entry> + <entry>[1280 KiB, 1536 KiB, 1792 KiB, 2 MiB]</entry> + </row> + <row> + <entry>512 KiB</entry> + <entry>[2560 KiB, 3 MiB, 3584 KiB, 4 MiB]</entry> + </row> + <row> + <entry>1 MiB</entry> + <entry>[5 MiB, 6 MiB, 7 MiB, 8 MiB]</entry> + </row> + <row> + <entry>2 MiB</entry> + <entry>[10 MiB, 12 MiB, 14 MiB, 16 MiB]</entry> + </row> + <row> + <entry>4 MiB</entry> + <entry>[20 MiB, 24 MiB, 28 MiB, 32 MiB]</entry> + </row> + <row> + <entry>8 MiB</entry> + <entry>[40 MiB, 48 MiB, 56 MiB, 64 MiB]</entry> + </row> + <row> + <entry>...</entry> + <entry>...</entry> + </row> + <row> + <entry>512 PiB</entry> + <entry>[2560 PiB, 3 EiB, 3584 PiB, 4 EiB]</entry> + </row> + <row> + <entry>1 EiB</entry> + <entry>[5 EiB, 6 EiB, 7 EiB]</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + <refsect1 id="mallctl_namespace"> + <title>MALLCTL NAMESPACE</title> + <para>The following names are defined in the namespace accessible via the + <function>mallctl*()</function> functions. Value types are specified in + parentheses, their readable/writable statuses are encoded as + <literal>rw</literal>, <literal>r-</literal>, <literal>-w</literal>, or + <literal>--</literal>, and required build configuration flags follow, if + any. A name element encoded as <literal><i></literal> or + <literal><j></literal> indicates an integer component, where the + integer varies from 0 to some upper value that must be determined via + introspection. In the case of <mallctl>stats.arenas.<i>.*</mallctl> + and <mallctl>arena.<i>.{initialized,purge,decay,dss}</mallctl>, + <literal><i></literal> equal to + <constant>MALLCTL_ARENAS_ALL</constant> can be used to operate on all arenas + or access the summation of statistics from all arenas; similarly + <literal><i></literal> equal to + <constant>MALLCTL_ARENAS_DESTROYED</constant> can be used to access the + summation of statistics from all destroyed arenas. These constants can be + utilized either via <function>mallctlnametomib()</function> followed by + <function>mallctlbymib()</function>, or via code such as the following: + <programlisting language="C"><![CDATA[ +#define STRINGIFY_HELPER(x) #x +#define STRINGIFY(x) STRINGIFY_HELPER(x) + +mallctl("arena." STRINGIFY(MALLCTL_ARENAS_ALL) ".decay", + NULL, NULL, NULL, 0);]]></programlisting> + Take special note of the <link + linkend="epoch"><mallctl>epoch</mallctl></link> mallctl, which controls + refreshing of cached dynamic statistics.</para> + + <variablelist> + <varlistentry id="version"> + <term> + <mallctl>version</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>Return the jemalloc version string.</para></listitem> + </varlistentry> + + <varlistentry id="epoch"> + <term> + <mallctl>epoch</mallctl> + (<type>uint64_t</type>) + <literal>rw</literal> + </term> + <listitem><para>If a value is passed in, refresh the data from which + the <function>mallctl*()</function> functions report values, + and increment the epoch. Return the current epoch. This is useful for + detecting whether another thread caused a refresh.</para></listitem> + </varlistentry> + + <varlistentry id="background_thread"> + <term> + <mallctl>background_thread</mallctl> + (<type>bool</type>) + <literal>rw</literal> + </term> + <listitem><para>Enable/disable internal background worker threads. When + set to true, background threads are created on demand (the number of + background threads will be no more than the number of CPUs or active + arenas). Threads run periodically, and handle <link + linkend="arena.i.decay">purging</link> asynchronously. When switching + off, background threads are terminated synchronously. Note that after + <citerefentry><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry> + function, the state in the child process will be disabled regardless + the state in parent process. See <link + linkend="stats.background_thread.num_threads"><mallctl>stats.background_thread</mallctl></link> + for related stats. <link + linkend="opt.background_thread"><mallctl>opt.background_thread</mallctl></link> + can be used to set the default option. This option is only available on + selected pthread-based platforms.</para></listitem> + </varlistentry> + + <varlistentry id="max_background_threads"> + <term> + <mallctl>max_background_threads</mallctl> + (<type>size_t</type>) + <literal>rw</literal> + </term> + <listitem><para>Maximum number of background worker threads that will + be created. This value is capped at <link + linkend="opt.max_background_threads"><mallctl>opt.max_background_threads</mallctl></link> at + startup.</para></listitem> + </varlistentry> + + <varlistentry id="config.cache_oblivious"> + <term> + <mallctl>config.cache_oblivious</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-cache-oblivious</option> was specified + during build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.debug"> + <term> + <mallctl>config.debug</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-debug</option> was specified during + build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.fill"> + <term> + <mallctl>config.fill</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-fill</option> was specified during + build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.lazy_lock"> + <term> + <mallctl>config.lazy_lock</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-lazy-lock</option> was specified + during build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.malloc_conf"> + <term> + <mallctl>config.malloc_conf</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>Embedded configure-time-specified run-time options + string, empty unless <option>--with-malloc-conf</option> was specified + during build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.prof"> + <term> + <mallctl>config.prof</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-prof</option> was specified during + build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.prof_libgcc"> + <term> + <mallctl>config.prof_libgcc</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--disable-prof-libgcc</option> was not + specified during build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.prof_libunwind"> + <term> + <mallctl>config.prof_libunwind</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-prof-libunwind</option> was specified + during build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.stats"> + <term> + <mallctl>config.stats</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-stats</option> was specified during + build configuration.</para></listitem> + </varlistentry> + + + <varlistentry id="config.utrace"> + <term> + <mallctl>config.utrace</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-utrace</option> was specified during + build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="config.xmalloc"> + <term> + <mallctl>config.xmalloc</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para><option>--enable-xmalloc</option> was specified during + build configuration.</para></listitem> + </varlistentry> + + <varlistentry id="opt.abort"> + <term> + <mallctl>opt.abort</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>Abort-on-warning enabled/disabled. If true, most + warnings are fatal. Note that runtime option warnings are not included + (see <link + linkend="opt.abort_conf"><mallctl>opt.abort_conf</mallctl></link> for + that). The process will call + <citerefentry><refentrytitle>abort</refentrytitle> + <manvolnum>3</manvolnum></citerefentry> in these cases. This option is + disabled by default unless <option>--enable-debug</option> is + specified during configuration, in which case it is enabled by default. + </para></listitem> + </varlistentry> + + <varlistentry id="opt.confirm_conf"> + <term> + <mallctl>opt.confirm_conf</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>Confirm-runtime-options-when-program-starts + enabled/disabled. If true, the string specified via + <option>--with-malloc-conf</option>, the string pointed to by the + global variable <varname>malloc_conf</varname>, the <quote>name</quote> + of the file referenced by the symbolic link named + <filename class="symlink">/etc/malloc.conf</filename>, and the value of + the environment variable <envar>MALLOC_CONF</envar>, will be printed in + order. Then, each option being set will be individually printed. This + option is disabled by default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.abort_conf"> + <term> + <mallctl>opt.abort_conf</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>Abort-on-invalid-configuration enabled/disabled. If + true, invalid runtime options are fatal. The process will call + <citerefentry><refentrytitle>abort</refentrytitle> + <manvolnum>3</manvolnum></citerefentry> in these cases. This option is + disabled by default unless <option>--enable-debug</option> is + specified during configuration, in which case it is enabled by default. + </para></listitem> + </varlistentry> + + <varlistentry id="opt.cache_oblivious"> + <term> + <mallctl>opt.cache_oblivious</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>Enable / Disable cache-oblivious large allocation + alignment, for large requests with no alignment constraints. If this + feature is disabled, all large allocations are page-aligned as an + implementation artifact, which can severely harm CPU cache utilization. + However, the cache-oblivious layout comes at the cost of one extra page + per large allocation, which in the most extreme case increases physical + memory usage for the 16 KiB size class to 20 KiB. This option is enabled + by default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.metadata_thp"> + <term> + <mallctl>opt.metadata_thp</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>Controls whether to allow jemalloc to use transparent + huge page (THP) for internal metadata (see <link + linkend="stats.metadata">stats.metadata</link>). <quote>always</quote> + allows such usage. <quote>auto</quote> uses no THP initially, but may + begin to do so when metadata usage reaches certain level. The default + is <quote>disabled</quote>.</para></listitem> + </varlistentry> + + <varlistentry id="opt.trust_madvise"> + <term> + <mallctl>opt.trust_madvise</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>If true, do not perform runtime check for MADV_DONTNEED, + to check that it actually zeros pages. The default is disabled on Linux + and enabled elsewhere.</para></listitem> + </varlistentry> + + <varlistentry id="opt.retain"> + <term> + <mallctl>opt.retain</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>If true, retain unused virtual memory for later reuse + rather than discarding it by calling + <citerefentry><refentrytitle>munmap</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> or equivalent (see <link + linkend="stats.retained">stats.retained</link> for related details). + It also makes jemalloc use <citerefentry> + <refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum> + </citerefentry> or equivalent in a more greedy way, mapping larger + chunks in one go. This option is disabled by default unless discarding + virtual memory is known to trigger platform-specific performance + problems, namely 1) for [64-bit] Linux, which has a quirk in its virtual + memory allocation algorithm that causes semi-permanent VM map holes + under normal jemalloc operation; and 2) for [64-bit] Windows, which + disallows split / merged regions with + <parameter><constant>MEM_RELEASE</constant></parameter>. Although the + same issues may present on 32-bit platforms as well, retaining virtual + memory for 32-bit Linux and Windows is disabled by default due to the + practical possibility of address space exhaustion. </para></listitem> + </varlistentry> + + <varlistentry id="opt.dss"> + <term> + <mallctl>opt.dss</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>dss (<citerefentry><refentrytitle>sbrk</refentrytitle> + <manvolnum>2</manvolnum></citerefentry>) allocation precedence as + related to <citerefentry><refentrytitle>mmap</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> allocation. The following + settings are supported if + <citerefentry><refentrytitle>sbrk</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> is supported by the operating + system: <quote>disabled</quote>, <quote>primary</quote>, and + <quote>secondary</quote>; otherwise only <quote>disabled</quote> is + supported. The default is <quote>secondary</quote> if + <citerefentry><refentrytitle>sbrk</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> is supported by the operating + system; <quote>disabled</quote> otherwise. + </para></listitem> + </varlistentry> + + <varlistentry id="opt.narenas"> + <term> + <mallctl>opt.narenas</mallctl> + (<type>unsigned</type>) + <literal>r-</literal> + </term> + <listitem><para>Maximum number of arenas to use for automatic + multiplexing of threads and arenas. The default is four times the + number of CPUs, or one if there is a single CPU.</para></listitem> + </varlistentry> + + <varlistentry id="opt.oversize_threshold"> + <term> + <mallctl>opt.oversize_threshold</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>The threshold in bytes of which requests are considered + oversize. Allocation requests with greater sizes are fulfilled from a + dedicated arena (automatically managed, however not within + <literal>narenas</literal>), in order to reduce fragmentation by not + mixing huge allocations with small ones. In addition, the decay API + guarantees on the extents greater than the specified threshold may be + overridden. Note that requests with arena index specified via + <constant>MALLOCX_ARENA</constant>, or threads associated with explicit + arenas will not be considered. The default threshold is 8MiB. Values + not within large size classes disables this feature.</para></listitem> + </varlistentry> + + <varlistentry id="opt.percpu_arena"> + <term> + <mallctl>opt.percpu_arena</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>Per CPU arena mode. Use the <quote>percpu</quote> + setting to enable this feature, which uses number of CPUs to determine + number of arenas, and bind threads to arenas dynamically based on the + CPU the thread runs on currently. <quote>phycpu</quote> setting uses + one arena per physical CPU, which means the two hyper threads on the + same CPU share one arena. Note that no runtime checking regarding the + availability of hyper threading is done at the moment. When set to + <quote>disabled</quote>, narenas and thread to arena association will + not be impacted by this option. The default is <quote>disabled</quote>. + </para></listitem> + </varlistentry> + + <varlistentry id="opt.background_thread"> + <term> + <mallctl>opt.background_thread</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>Internal background worker threads enabled/disabled. + Because of potential circular dependencies, enabling background thread + using this option may cause crash or deadlock during initialization. For + a reliable way to use this feature, see <link + linkend="background_thread">background_thread</link> for dynamic control + options and details. This option is disabled by + default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.max_background_threads"> + <term> + <mallctl>opt.max_background_threads</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Maximum number of background threads that will be created + if <link linkend="background_thread">background_thread</link> is set. + Defaults to number of cpus.</para></listitem> + </varlistentry> + + <varlistentry id="opt.dirty_decay_ms"> + <term> + <mallctl>opt.dirty_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Approximate time in milliseconds from the creation of a + set of unused dirty pages until an equivalent set of unused dirty pages + is purged (i.e. converted to muzzy via e.g. + <function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function> + if supported by the operating system, or converted to clean otherwise) + and/or reused. Dirty pages are defined as previously having been + potentially written to by the application, and therefore consuming + physical memory, yet having no current use. The pages are incrementally + purged according to a sigmoidal decay curve that starts and ends with + zero purge rate. A decay time of 0 causes all unused dirty pages to be + purged immediately upon creation. A decay time of -1 disables purging. + The default decay time is 10 seconds. See <link + linkend="arenas.dirty_decay_ms"><mallctl>arenas.dirty_decay_ms</mallctl></link> + and <link + linkend="arena.i.dirty_decay_ms"><mallctl>arena.<i>.dirty_decay_ms</mallctl></link> + for related dynamic control options. See <link + linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> + for a description of muzzy pages.for a description of muzzy pages. Note + that when the <link + linkend="opt.oversize_threshold"><mallctl>oversize_threshold</mallctl></link> + feature is enabled, the arenas reserved for oversize requests may have + its own default decay settings.</para></listitem> + </varlistentry> + + <varlistentry id="opt.muzzy_decay_ms"> + <term> + <mallctl>opt.muzzy_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Approximate time in milliseconds from the creation of a + set of unused muzzy pages until an equivalent set of unused muzzy pages + is purged (i.e. converted to clean) and/or reused. Muzzy pages are + defined as previously having been unused dirty pages that were + subsequently purged in a manner that left them subject to the + reclamation whims of the operating system (e.g. + <function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function>), + and therefore in an indeterminate state. The pages are incrementally + purged according to a sigmoidal decay curve that starts and ends with + zero purge rate. A decay time of 0 causes all unused muzzy pages to be + purged immediately upon creation. A decay time of -1 disables purging. + The default decay time is 10 seconds. See <link + linkend="arenas.muzzy_decay_ms"><mallctl>arenas.muzzy_decay_ms</mallctl></link> + and <link + linkend="arena.i.muzzy_decay_ms"><mallctl>arena.<i>.muzzy_decay_ms</mallctl></link> + for related dynamic control options.</para></listitem> + </varlistentry> + + <varlistentry id="opt.lg_extent_max_active_fit"> + <term> + <mallctl>opt.lg_extent_max_active_fit</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>When reusing dirty extents, this determines the (log + base 2 of the) maximum ratio between the size of the active extent + selected (to split off from) and the size of the requested allocation. + This prevents the splitting of large active extents for smaller + allocations, which can reduce fragmentation over the long run + (especially for non-active extents). Lower value may reduce + fragmentation, at the cost of extra active extents. The default value + is 6, which gives a maximum ratio of 64 (2^6).</para></listitem> + </varlistentry> + + <varlistentry id="opt.stats_print"> + <term> + <mallctl>opt.stats_print</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>Enable/disable statistics printing at exit. If + enabled, the <function>malloc_stats_print()</function> + function is called at program exit via an + <citerefentry><refentrytitle>atexit</refentrytitle> + <manvolnum>3</manvolnum></citerefentry> function. <link + linkend="opt.stats_print_opts"><mallctl>opt.stats_print_opts</mallctl></link> + can be combined to specify output options. If + <option>--enable-stats</option> is specified during configuration, this + has the potential to cause deadlock for a multi-threaded process that + exits while one or more threads are executing in the memory allocation + functions. Furthermore, <function>atexit()</function> may + allocate memory during application initialization and then deadlock + internally when jemalloc in turn calls + <function>atexit()</function>, so this option is not + universally usable (though the application can register its own + <function>atexit()</function> function with equivalent + functionality). Therefore, this option should only be used with care; + it is primarily intended as a performance tuning aid during application + development. This option is disabled by default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.stats_print_opts"> + <term> + <mallctl>opt.stats_print_opts</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>Options (the <parameter>opts</parameter> string) to pass + to the <function>malloc_stats_print()</function> at exit (enabled + through <link + linkend="opt.stats_print"><mallctl>opt.stats_print</mallctl></link>). See + available options in <link + linkend="malloc_stats_print_opts"><function>malloc_stats_print()</function></link>. + Has no effect unless <link + linkend="opt.stats_print"><mallctl>opt.stats_print</mallctl></link> is + enabled. The default is <quote></quote>.</para></listitem> + </varlistentry> + + <varlistentry id="opt.stats_interval"> + <term> + <mallctl>opt.stats_interval</mallctl> + (<type>int64_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Average interval between statistics outputs, as measured + in bytes of allocation activity. The actual interval may be sporadic + because decentralized event counters are used to avoid synchronization + bottlenecks. The output may be triggered on any thread, which then + calls <function>malloc_stats_print()</function>. <link + linkend="opt.stats_interval_opts"><mallctl>opt.stats_interval_opts</mallctl></link> + can be combined to specify output options. By default, + interval-triggered stats output is disabled (encoded as + -1).</para></listitem> + </varlistentry> + + <varlistentry id="opt.stats_interval_opts"> + <term> + <mallctl>opt.stats_interval_opts</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>Options (the <parameter>opts</parameter> string) to pass + to the <function>malloc_stats_print()</function> for interval based + statistics printing (enabled + through <link + linkend="opt.stats_interval"><mallctl>opt.stats_interval</mallctl></link>). See + available options in <link + linkend="malloc_stats_print_opts"><function>malloc_stats_print()</function></link>. + Has no effect unless <link + linkend="opt.stats_interval"><mallctl>opt.stats_interval</mallctl></link> is + enabled. The default is <quote></quote>.</para></listitem> + </varlistentry> + + <varlistentry id="opt.junk"> + <term> + <mallctl>opt.junk</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + [<option>--enable-fill</option>] + </term> + <listitem><para>Junk filling. If set to <quote>alloc</quote>, each byte + of uninitialized allocated memory will be initialized to + <literal>0xa5</literal>. If set to <quote>free</quote>, all deallocated + memory will be initialized to <literal>0x5a</literal>. If set to + <quote>true</quote>, both allocated and deallocated memory will be + initialized, and if set to <quote>false</quote>, junk filling be + disabled entirely. This is intended for debugging and will impact + performance negatively. This option is <quote>false</quote> by default + unless <option>--enable-debug</option> is specified during + configuration, in which case it is <quote>true</quote> by + default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.zero"> + <term> + <mallctl>opt.zero</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-fill</option>] + </term> + <listitem><para>Zero filling enabled/disabled. If enabled, each byte + of uninitialized allocated memory will be initialized to 0. Note that + this initialization only happens once for each byte, so + <function>realloc()</function> and + <function>rallocx()</function> calls do not zero memory that + was previously allocated. This is intended for debugging and will + impact performance negatively. This option is disabled by default. + </para></listitem> + </varlistentry> + + <varlistentry id="opt.utrace"> + <term> + <mallctl>opt.utrace</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-utrace</option>] + </term> + <listitem><para>Allocation tracing based on + <citerefentry><refentrytitle>utrace</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> enabled/disabled. This option + is disabled by default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.xmalloc"> + <term> + <mallctl>opt.xmalloc</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-xmalloc</option>] + </term> + <listitem><para>Abort-on-out-of-memory enabled/disabled. If enabled, + rather than returning failure for any allocation function, display a + diagnostic message on <constant>STDERR_FILENO</constant> and cause the + program to drop core (using + <citerefentry><refentrytitle>abort</refentrytitle> + <manvolnum>3</manvolnum></citerefentry>). If an application is + designed to depend on this behavior, set the option at compile time by + including the following in the source code: + <programlisting language="C"><![CDATA[ +malloc_conf = "xmalloc:true";]]></programlisting> + This option is disabled by default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.tcache"> + <term> + <mallctl>opt.tcache</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>Thread-specific caching (tcache) enabled/disabled. When + there are multiple threads, each thread uses a tcache for objects up to + a certain size. Thread-specific caching allows many allocations to be + satisfied without performing any thread synchronization, at the cost of + increased memory use. See the <link + linkend="opt.tcache_max"><mallctl>opt.tcache_max</mallctl></link> + option for related tuning information. This option is enabled by + default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.tcache_max"> + <term> + <mallctl>opt.tcache_max</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Maximum size class to cache in the thread-specific cache + (tcache). At a minimum, the first size class is cached; and at a + maximum, size classes up to 8 MiB can be cached. The default maximum is + 32 KiB (2^15). As a convenience, this may also be set by specifying + lg_tcache_max, which will be taken to be the base-2 logarithm of the + setting of tcache_max.</para></listitem> + </varlistentry> + + <varlistentry id="opt.thp"> + <term> + <mallctl>opt.thp</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>Transparent hugepage (THP) mode. Settings "always", + "never" and "default" are available if THP is supported by the operating + system. The "always" setting enables transparent hugepage for all user + memory mappings with + <parameter><constant>MADV_HUGEPAGE</constant></parameter>; "never" + ensures no transparent hugepage with + <parameter><constant>MADV_NOHUGEPAGE</constant></parameter>; the default + setting "default" makes no changes. Note that: this option does not + affect THP for jemalloc internal metadata (see <link + linkend="opt.metadata_thp"><mallctl>opt.metadata_thp</mallctl></link>); + in addition, for arenas with customized <link + linkend="arena.i.extent_hooks"><mallctl>extent_hooks</mallctl></link>, + this option is bypassed as it is implemented as part of the default + extent hooks.</para></listitem> + </varlistentry> + + <varlistentry id="opt.prof"> + <term> + <mallctl>opt.prof</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Memory profiling enabled/disabled. If enabled, profile + memory allocation activity. See the <link + linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link> + option for on-the-fly activation/deactivation. See the <link + linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link> + option for probabilistic sampling control. See the <link + linkend="opt.prof_accum"><mallctl>opt.prof_accum</mallctl></link> + option for control of cumulative sample reporting. See the <link + linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link> + option for information on interval-triggered profile dumping, the <link + linkend="opt.prof_gdump"><mallctl>opt.prof_gdump</mallctl></link> + option for information on high-water-triggered profile dumping, and the + <link linkend="opt.prof_final"><mallctl>opt.prof_final</mallctl></link> + option for final profile dumping. Profile output is compatible with + the <command>jeprof</command> command, which is based on the + <command>pprof</command> that is developed as part of the <ulink + url="http://code.google.com/p/gperftools/">gperftools + package</ulink>. See <link linkend="heap_profile_format">HEAP PROFILE + FORMAT</link> for heap profile format documentation.</para></listitem> + </varlistentry> + + <varlistentry id="opt.prof_prefix"> + <term> + <mallctl>opt.prof_prefix</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Filename prefix for profile dumps. If the prefix is + set to the empty string, no automatic dumps will occur; this is + primarily useful for disabling the automatic final heap dump (which + also disables leak reporting, if enabled). The default prefix is + <filename>jeprof</filename>. This prefix value can be overridden by + <link linkend="prof.prefix"><mallctl>prof.prefix</mallctl></link>. + </para></listitem> + </varlistentry> + + <varlistentry id="opt.prof_active"> + <term> + <mallctl>opt.prof_active</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Profiling activated/deactivated. This is a secondary + control mechanism that makes it possible to start the application with + profiling enabled (see the <link + linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option) but + inactive, then toggle profiling at any time during program execution + with the <link + linkend="prof.active"><mallctl>prof.active</mallctl></link> mallctl. + This option is enabled by default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.prof_thread_active_init"> + <term> + <mallctl>opt.prof_thread_active_init</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Initial setting for <link + linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> + in newly created threads. The initial setting for newly created threads + can also be changed during execution via the <link + linkend="prof.thread_active_init"><mallctl>prof.thread_active_init</mallctl></link> + mallctl. This option is enabled by default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.lg_prof_sample"> + <term> + <mallctl>opt.lg_prof_sample</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Average interval (log base 2) between allocation + samples, as measured in bytes of allocation activity. Increasing the + sampling interval decreases profile fidelity, but also decreases the + computational overhead. The default sample interval is 512 KiB (2^19 + B).</para></listitem> + </varlistentry> + + <varlistentry id="opt.prof_accum"> + <term> + <mallctl>opt.prof_accum</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Reporting of cumulative object/byte counts in profile + dumps enabled/disabled. If this option is enabled, every unique + backtrace must be stored for the duration of execution. Depending on + the application, this can impose a large memory overhead, and the + cumulative counts are not always of interest. This option is disabled + by default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.lg_prof_interval"> + <term> + <mallctl>opt.lg_prof_interval</mallctl> + (<type>ssize_t</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Average interval (log base 2) between memory profile + dumps, as measured in bytes of allocation activity. The actual + interval between dumps may be sporadic because decentralized allocation + counters are used to avoid synchronization bottlenecks. Profiles are + dumped to files named according to the pattern + <filename><prefix>.<pid>.<seq>.i<iseq>.heap</filename>, + where <literal><prefix></literal> is controlled by the + <link + linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> and + <link linkend="prof.prefix"><mallctl>prof.prefix</mallctl></link> + options. By default, interval-triggered profile dumping is disabled + (encoded as -1). + </para></listitem> + </varlistentry> + + <varlistentry id="opt.prof_gdump"> + <term> + <mallctl>opt.prof_gdump</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Set the initial state of <link + linkend="prof.gdump"><mallctl>prof.gdump</mallctl></link>, which when + enabled triggers a memory profile dump every time the total virtual + memory exceeds the previous maximum. This option is disabled by + default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.prof_final"> + <term> + <mallctl>opt.prof_final</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Use an + <citerefentry><refentrytitle>atexit</refentrytitle> + <manvolnum>3</manvolnum></citerefentry> function to dump final memory + usage to a file named according to the pattern + <filename><prefix>.<pid>.<seq>.f.heap</filename>, + where <literal><prefix></literal> is controlled by the <link + linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> and + <link linkend="prof.prefix"><mallctl>prof.prefix</mallctl></link> + options. Note that <function>atexit()</function> may allocate + memory during application initialization and then deadlock internally + when jemalloc in turn calls <function>atexit()</function>, so + this option is not universally usable (though the application can + register its own <function>atexit()</function> function with + equivalent functionality). This option is disabled by + default.</para></listitem> + </varlistentry> + + <varlistentry id="opt.prof_leak"> + <term> + <mallctl>opt.prof_leak</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Leak reporting enabled/disabled. If enabled, use an + <citerefentry><refentrytitle>atexit</refentrytitle> + <manvolnum>3</manvolnum></citerefentry> function to report memory leaks + detected by allocation sampling. See the + <link linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option for + information on analyzing heap profile output. Works only when combined + with <link linkend="opt.prof_final"><mallctl>opt.prof_final</mallctl> + </link>, otherwise does nothing. This option is disabled by default. + </para></listitem> + </varlistentry> + + <varlistentry id="opt.prof_leak_error"> + <term> + <mallctl>opt.prof_leak_error</mallctl> + (<type>bool</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Similar to <link linkend="opt.prof_leak"><mallctl> + opt.prof_leak</mallctl></link>, but makes the process exit with error + code 1 if a memory leak is detected. This option supersedes + <link linkend="opt.prof_leak"><mallctl>opt.prof_leak</mallctl></link>, + meaning that if both are specified, this option takes precedence. When + enabled, also enables <link linkend="opt.prof_leak"><mallctl> + opt.prof_leak</mallctl></link>. Works only when combined with + <link linkend="opt.prof_final"><mallctl>opt.prof_final</mallctl></link>, + otherwise does nothing. This option is disabled by default. + </para></listitem> + </varlistentry> + + <varlistentry id="opt.zero_realloc"> + <term> + <mallctl>opt.zero_realloc</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para> Determines the behavior of + <function>realloc()</function> when passed a value of zero for the new + size. <quote>alloc</quote> treats this as an allocation of size zero + (and returns a non-null result except in case of resource exhaustion). + <quote>free</quote> treats this as a deallocation of the pointer, and + returns <constant>NULL</constant> without setting + <varname>errno</varname>. <quote>abort</quote> aborts the process if + zero is passed. The default is <quote>free</quote> on Linux and + Windows, and <quote>alloc</quote> elsewhere.</para> + + <para>There is considerable divergence of behaviors across + implementations in handling this case. Many have the behavior of + <quote>free</quote>. This can introduce security vulnerabilities, since + a <constant>NULL</constant> return value indicates failure, and the + continued validity of the passed-in pointer (per POSIX and C11). + <quote>alloc</quote> is safe, but can cause leaks in programs that + expect the common behavior. Programs intended to be portable and + leak-free cannot assume either behavior, and must therefore never call + realloc with a size of 0. The <quote>abort</quote> option enables these + testing this behavior.</para></listitem> + </varlistentry> + + <varlistentry id="thread.arena"> + <term> + <mallctl>thread.arena</mallctl> + (<type>unsigned</type>) + <literal>rw</literal> + </term> + <listitem><para>Get or set the arena associated with the calling + thread. If the specified arena was not initialized beforehand (see the + <link + linkend="arena.i.initialized"><mallctl>arena.i.initialized</mallctl></link> + mallctl), it will be automatically initialized as a side effect of + calling this interface.</para></listitem> + </varlistentry> + + <varlistentry id="thread.allocated"> + <term> + <mallctl>thread.allocated</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Get the total number of bytes ever allocated by the + calling thread. This counter has the potential to wrap around; it is + up to the application to appropriately interpret the counter in such + cases.</para></listitem> + </varlistentry> + + <varlistentry id="thread.allocatedp"> + <term> + <mallctl>thread.allocatedp</mallctl> + (<type>uint64_t *</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Get a pointer to the the value that is returned by the + <link + linkend="thread.allocated"><mallctl>thread.allocated</mallctl></link> + mallctl. This is useful for avoiding the overhead of repeated + <function>mallctl*()</function> calls. Note that the underlying counter + should not be modified by the application.</para></listitem> + </varlistentry> + + <varlistentry id="thread.deallocated"> + <term> + <mallctl>thread.deallocated</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Get the total number of bytes ever deallocated by the + calling thread. This counter has the potential to wrap around; it is + up to the application to appropriately interpret the counter in such + cases.</para></listitem> + </varlistentry> + + <varlistentry id="thread.deallocatedp"> + <term> + <mallctl>thread.deallocatedp</mallctl> + (<type>uint64_t *</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Get a pointer to the the value that is returned by the + <link + linkend="thread.deallocated"><mallctl>thread.deallocated</mallctl></link> + mallctl. This is useful for avoiding the overhead of repeated + <function>mallctl*()</function> calls. Note that the underlying counter + should not be modified by the application.</para></listitem> + </varlistentry> + + <varlistentry id="thread.peak.read"> + <term> + <mallctl>thread.peak.read</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Get an approximation of the maximum value of the + difference between the number of bytes allocated and the number of bytes + deallocated by the calling thread since the last call to <link + linkend="thread.peak.reset"><mallctl>thread.peak.reset</mallctl></link>, + or since the thread's creation if it has not called <link + linkend="thread.peak.reset"><mallctl>thread.peak.reset</mallctl></link>. + No guarantees are made about the quality of the approximation, but + jemalloc currently endeavors to maintain accuracy to within one hundred + kilobytes. + </para></listitem> + </varlistentry> + + <varlistentry id="thread.peak.reset"> + <term> + <mallctl>thread.peak.reset</mallctl> + (<type>void</type>) + <literal>--</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Resets the counter for net bytes allocated in the calling + thread to zero. This affects subsequent calls to <link + linkend="thread.peak.read"><mallctl>thread.peak.read</mallctl></link>, + but not the values returned by <link + linkend="thread.allocated"><mallctl>thread.allocated</mallctl></link> + or <link + linkend="thread.deallocated"><mallctl>thread.deallocated</mallctl></link>. + </para></listitem> + </varlistentry> + + <varlistentry id="thread.tcache.enabled"> + <term> + <mallctl>thread.tcache.enabled</mallctl> + (<type>bool</type>) + <literal>rw</literal> + </term> + <listitem><para>Enable/disable calling thread's tcache. The tcache is + implicitly flushed as a side effect of becoming + disabled (see <link + linkend="thread.tcache.flush"><mallctl>thread.tcache.flush</mallctl></link>). + </para></listitem> + </varlistentry> + + <varlistentry id="thread.tcache.flush"> + <term> + <mallctl>thread.tcache.flush</mallctl> + (<type>void</type>) + <literal>--</literal> + </term> + <listitem><para>Flush calling thread's thread-specific cache (tcache). + This interface releases all cached objects and internal data structures + associated with the calling thread's tcache. Ordinarily, this interface + need not be called, since automatic periodic incremental garbage + collection occurs, and the thread cache is automatically discarded when + a thread exits. However, garbage collection is triggered by allocation + activity, so it is possible for a thread that stops + allocating/deallocating to retain its cache indefinitely, in which case + the developer may find manual flushing useful.</para></listitem> + </varlistentry> + + <varlistentry id="thread.prof.name"> + <term> + <mallctl>thread.prof.name</mallctl> + (<type>const char *</type>) + <literal>r-</literal> or + <literal>-w</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Get/set the descriptive name associated with the calling + thread in memory profile dumps. An internal copy of the name string is + created, so the input string need not be maintained after this interface + completes execution. The output string of this interface should be + copied for non-ephemeral uses, because multiple implementation details + can cause asynchronous string deallocation. Furthermore, each + invocation of this interface can only read or write; simultaneous + read/write is not supported due to string lifetime limitations. The + name string must be nil-terminated and comprised only of characters in + the sets recognized + by <citerefentry><refentrytitle>isgraph</refentrytitle> + <manvolnum>3</manvolnum></citerefentry> and + <citerefentry><refentrytitle>isblank</refentrytitle> + <manvolnum>3</manvolnum></citerefentry>.</para></listitem> + </varlistentry> + + <varlistentry id="thread.prof.active"> + <term> + <mallctl>thread.prof.active</mallctl> + (<type>bool</type>) + <literal>rw</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Control whether sampling is currently active for the + calling thread. This is an activation mechanism in addition to <link + linkend="prof.active"><mallctl>prof.active</mallctl></link>; both must + be active for the calling thread to sample. This flag is enabled by + default.</para></listitem> + </varlistentry> + + <varlistentry id="thread.idle"> + <term> + <mallctl>thread.idle</mallctl> + (<type>void</type>) + <literal>--</literal> + </term> + <listitem><para>Hints to jemalloc that the calling thread will be idle + for some nontrivial period of time (say, on the order of seconds), and + that doing some cleanup operations may be beneficial. There are no + guarantees as to what specific operations will be performed; currently + this flushes the caller's tcache and may (according to some heuristic) + purge its associated arena.</para> + <para>This is not intended to be a general-purpose background activity + mechanism, and threads should not wake up multiple times solely to call + it. Rather, a thread waiting for a task should do a timed wait first, + call <link linkend="thread.idle"><mallctl>thread.idle</mallctl></link> + if no task appears in the timeout interval, and then do an untimed wait. + For such a background activity mechanism, see + <link linkend="background_thread"><mallctl>background_thread</mallctl></link>. + </para></listitem> + </varlistentry> + + <varlistentry id="tcache.create"> + <term> + <mallctl>tcache.create</mallctl> + (<type>unsigned</type>) + <literal>r-</literal> + </term> + <listitem><para>Create an explicit thread-specific cache (tcache) and + return an identifier that can be passed to the <link + linkend="MALLOCX_TCACHE"><constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant></link> + macro to explicitly use the specified cache rather than the + automatically managed one that is used by default. Each explicit cache + can be used by only one thread at a time; the application must assure + that this constraint holds. + </para> + + <para>If the amount of space supplied for storing the thread-specific + cache identifier does not equal + <code language="C">sizeof(<type>unsigned</type>)</code>, no + thread-specific cache will be created, no data will be written to the + space pointed by <parameter>oldp</parameter>, and + <parameter>*oldlenp</parameter> will be set to 0. + </para></listitem> + + </varlistentry> + + <varlistentry id="tcache.flush"> + <term> + <mallctl>tcache.flush</mallctl> + (<type>unsigned</type>) + <literal>-w</literal> + </term> + <listitem><para>Flush the specified thread-specific cache (tcache). The + same considerations apply to this interface as to <link + linkend="thread.tcache.flush"><mallctl>thread.tcache.flush</mallctl></link>, + except that the tcache will never be automatically discarded. + </para></listitem> + </varlistentry> + + <varlistentry id="tcache.destroy"> + <term> + <mallctl>tcache.destroy</mallctl> + (<type>unsigned</type>) + <literal>-w</literal> + </term> + <listitem><para>Flush the specified thread-specific cache (tcache) and + make the identifier available for use during a future tcache creation. + </para></listitem> + </varlistentry> + + <varlistentry id="arena.i.initialized"> + <term> + <mallctl>arena.<i>.initialized</mallctl> + (<type>bool</type>) + <literal>r-</literal> + </term> + <listitem><para>Get whether the specified arena's statistics are + initialized (i.e. the arena was initialized prior to the current epoch). + This interface can also be nominally used to query whether the merged + statistics corresponding to <constant>MALLCTL_ARENAS_ALL</constant> are + initialized (always true).</para></listitem> + </varlistentry> + + <varlistentry id="arena.i.decay"> + <term> + <mallctl>arena.<i>.decay</mallctl> + (<type>void</type>) + <literal>--</literal> + </term> + <listitem><para>Trigger decay-based purging of unused dirty/muzzy pages + for arena <i>, or for all arenas if <i> equals + <constant>MALLCTL_ARENAS_ALL</constant>. The proportion of unused + dirty/muzzy pages to be purged depends on the current time; see <link + linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> + and <link + linkend="opt.muzzy_decay_ms"><mallctl>opt.muzy_decay_ms</mallctl></link> + for details.</para></listitem> + </varlistentry> + + <varlistentry id="arena.i.purge"> + <term> + <mallctl>arena.<i>.purge</mallctl> + (<type>void</type>) + <literal>--</literal> + </term> + <listitem><para>Purge all unused dirty pages for arena <i>, or for + all arenas if <i> equals <constant>MALLCTL_ARENAS_ALL</constant>. + </para></listitem> + </varlistentry> + + <varlistentry id="arena.i.reset"> + <term> + <mallctl>arena.<i>.reset</mallctl> + (<type>void</type>) + <literal>--</literal> + </term> + <listitem><para>Discard all of the arena's extant allocations. This + interface can only be used with arenas explicitly created via <link + linkend="arenas.create"><mallctl>arenas.create</mallctl></link>. None + of the arena's discarded/cached allocations may accessed afterward. As + part of this requirement, all thread caches which were used to + allocate/deallocate in conjunction with the arena must be flushed + beforehand.</para></listitem> + </varlistentry> + + <varlistentry id="arena.i.destroy"> + <term> + <mallctl>arena.<i>.destroy</mallctl> + (<type>void</type>) + <literal>--</literal> + </term> + <listitem><para>Destroy the arena. Discard all of the arena's extant + allocations using the same mechanism as for <link + linkend="arena.i.reset"><mallctl>arena.<i>.reset</mallctl></link> + (with all the same constraints and side effects), merge the arena stats + into those accessible at arena index + <constant>MALLCTL_ARENAS_DESTROYED</constant>, and then completely + discard all metadata associated with the arena. Future calls to <link + linkend="arenas.create"><mallctl>arenas.create</mallctl></link> may + recycle the arena index. Destruction will fail if any threads are + currently associated with the arena as a result of calls to <link + linkend="thread.arena"><mallctl>thread.arena</mallctl></link>.</para></listitem> + </varlistentry> + + <varlistentry id="arena.i.dss"> + <term> + <mallctl>arena.<i>.dss</mallctl> + (<type>const char *</type>) + <literal>rw</literal> + </term> + <listitem><para>Set the precedence of dss allocation as related to mmap + allocation for arena <i>, or for all arenas if <i> equals + <constant>MALLCTL_ARENAS_ALL</constant>. See <link + linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for supported + settings.</para></listitem> + </varlistentry> + + <varlistentry id="arena.i.dirty_decay_ms"> + <term> + <mallctl>arena.<i>.dirty_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>rw</literal> + </term> + <listitem><para>Current per-arena approximate time in milliseconds from + the creation of a set of unused dirty pages until an equivalent set of + unused dirty pages is purged and/or reused. Each time this interface is + set, all currently unused dirty pages are considered to have fully + decayed, which causes immediate purging of all unused dirty pages unless + the decay time is set to -1 (i.e. purging disabled). See <link + linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> + for additional information.</para></listitem> + </varlistentry> + + <varlistentry id="arena.i.muzzy_decay_ms"> + <term> + <mallctl>arena.<i>.muzzy_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>rw</literal> + </term> + <listitem><para>Current per-arena approximate time in milliseconds from + the creation of a set of unused muzzy pages until an equivalent set of + unused muzzy pages is purged and/or reused. Each time this interface is + set, all currently unused muzzy pages are considered to have fully + decayed, which causes immediate purging of all unused muzzy pages unless + the decay time is set to -1 (i.e. purging disabled). See <link + linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> + for additional information.</para></listitem> + </varlistentry> + + <varlistentry id="arena.i.retain_grow_limit"> + <term> + <mallctl>arena.<i>.retain_grow_limit</mallctl> + (<type>size_t</type>) + <literal>rw</literal> + </term> + <listitem><para>Maximum size to grow retained region (only relevant when + <link linkend="opt.retain"><mallctl>opt.retain</mallctl></link> is + enabled). This controls the maximum increment to expand virtual memory, + or allocation through <link + linkend="arena.i.extent_hooks"><mallctl>arena.<i>extent_hooks</mallctl></link>. + In particular, if customized extent hooks reserve physical memory + (e.g. 1G huge pages), this is useful to control the allocation hook's + input size. The default is no limit.</para></listitem> + </varlistentry> + + <varlistentry id="arena.i.extent_hooks"> + <term> + <mallctl>arena.<i>.extent_hooks</mallctl> + (<type>extent_hooks_t *</type>) + <literal>rw</literal> + </term> + <listitem><para>Get or set the extent management hook functions for + arena <i>. The functions must be capable of operating on all + extant extents associated with arena <i>, usually by passing + unknown extents to the replaced functions. In practice, it is feasible + to control allocation for arenas explicitly created via <link + linkend="arenas.create"><mallctl>arenas.create</mallctl></link> such + that all extents originate from an application-supplied extent allocator + (by specifying the custom extent hook functions during arena creation). + However, the API guarantees for the automatically created arenas may be + relaxed -- hooks set there may be called in a "best effort" fashion; in + addition there may be extents created prior to the application having an + opportunity to take over extent allocation.</para> + + <programlisting language="C"><![CDATA[ +typedef extent_hooks_s extent_hooks_t; +struct extent_hooks_s { + extent_alloc_t *alloc; + extent_dalloc_t *dalloc; + extent_destroy_t *destroy; + extent_commit_t *commit; + extent_decommit_t *decommit; + extent_purge_t *purge_lazy; + extent_purge_t *purge_forced; + extent_split_t *split; + extent_merge_t *merge; +};]]></programlisting> + <para>The <type>extent_hooks_t</type> structure comprises function + pointers which are described individually below. jemalloc uses these + functions to manage extent lifetime, which starts off with allocation of + mapped committed memory, in the simplest case followed by deallocation. + However, there are performance and platform reasons to retain extents + for later reuse. Cleanup attempts cascade from deallocation to decommit + to forced purging to lazy purging, which gives the extent management + functions opportunities to reject the most permanent cleanup operations + in favor of less permanent (and often less costly) operations. All + operations except allocation can be universally opted out of by setting + the hook pointers to <constant>NULL</constant>, or selectively opted out + of by returning failure. Note that once the extent hook is set, the + structure is accessed directly by the associated arenas, so it must + remain valid for the entire lifetime of the arenas.</para> + + <funcsynopsis><funcprototype> + <funcdef>typedef void *<function>(extent_alloc_t)</function></funcdef> + <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> + <paramdef>void *<parameter>new_addr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>size_t <parameter>alignment</parameter></paramdef> + <paramdef>bool *<parameter>zero</parameter></paramdef> + <paramdef>bool *<parameter>commit</parameter></paramdef> + <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> + </funcprototype></funcsynopsis> + <literallayout></literallayout> + <para>An extent allocation function conforms to the + <type>extent_alloc_t</type> type and upon success returns a pointer to + <parameter>size</parameter> bytes of mapped memory on behalf of arena + <parameter>arena_ind</parameter> such that the extent's base address is + a multiple of <parameter>alignment</parameter>, as well as setting + <parameter>*zero</parameter> to indicate whether the extent is zeroed + and <parameter>*commit</parameter> to indicate whether the extent is + committed. Upon error the function returns <constant>NULL</constant> + and leaves <parameter>*zero</parameter> and + <parameter>*commit</parameter> unmodified. The + <parameter>size</parameter> parameter is always a multiple of the page + size. The <parameter>alignment</parameter> parameter is always a power + of two at least as large as the page size. Zeroing is mandatory if + <parameter>*zero</parameter> is true upon function entry. Committing is + mandatory if <parameter>*commit</parameter> is true upon function entry. + If <parameter>new_addr</parameter> is not <constant>NULL</constant>, the + returned pointer must be <parameter>new_addr</parameter> on success or + <constant>NULL</constant> on error. Committed memory may be committed + in absolute terms as on a system that does not overcommit, or in + implicit terms as on a system that overcommits and satisfies physical + memory needs on demand via soft page faults. Note that replacing the + default extent allocation function makes the arena's <link + linkend="arena.i.dss"><mallctl>arena.<i>.dss</mallctl></link> + setting irrelevant.</para> + + <funcsynopsis><funcprototype> + <funcdef>typedef bool <function>(extent_dalloc_t)</function></funcdef> + <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> + <paramdef>void *<parameter>addr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>bool <parameter>committed</parameter></paramdef> + <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> + </funcprototype></funcsynopsis> + <literallayout></literallayout> + <para> + An extent deallocation function conforms to the + <type>extent_dalloc_t</type> type and deallocates an extent at given + <parameter>addr</parameter> and <parameter>size</parameter> with + <parameter>committed</parameter>/decommited memory as indicated, on + behalf of arena <parameter>arena_ind</parameter>, returning false upon + success. If the function returns true, this indicates opt-out from + deallocation; the virtual memory mapping associated with the extent + remains mapped, in the same commit state, and available for future use, + in which case it will be automatically retained for later reuse.</para> + + <funcsynopsis><funcprototype> + <funcdef>typedef void <function>(extent_destroy_t)</function></funcdef> + <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> + <paramdef>void *<parameter>addr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>bool <parameter>committed</parameter></paramdef> + <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> + </funcprototype></funcsynopsis> + <literallayout></literallayout> + <para> + An extent destruction function conforms to the + <type>extent_destroy_t</type> type and unconditionally destroys an + extent at given <parameter>addr</parameter> and + <parameter>size</parameter> with + <parameter>committed</parameter>/decommited memory as indicated, on + behalf of arena <parameter>arena_ind</parameter>. This function may be + called to destroy retained extents during arena destruction (see <link + linkend="arena.i.destroy"><mallctl>arena.<i>.destroy</mallctl></link>).</para> + + <funcsynopsis><funcprototype> + <funcdef>typedef bool <function>(extent_commit_t)</function></funcdef> + <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> + <paramdef>void *<parameter>addr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>size_t <parameter>offset</parameter></paramdef> + <paramdef>size_t <parameter>length</parameter></paramdef> + <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> + </funcprototype></funcsynopsis> + <literallayout></literallayout> + <para>An extent commit function conforms to the + <type>extent_commit_t</type> type and commits zeroed physical memory to + back pages within an extent at given <parameter>addr</parameter> and + <parameter>size</parameter> at <parameter>offset</parameter> bytes, + extending for <parameter>length</parameter> on behalf of arena + <parameter>arena_ind</parameter>, returning false upon success. + Committed memory may be committed in absolute terms as on a system that + does not overcommit, or in implicit terms as on a system that + overcommits and satisfies physical memory needs on demand via soft page + faults. If the function returns true, this indicates insufficient + physical memory to satisfy the request.</para> + + <funcsynopsis><funcprototype> + <funcdef>typedef bool <function>(extent_decommit_t)</function></funcdef> + <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> + <paramdef>void *<parameter>addr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>size_t <parameter>offset</parameter></paramdef> + <paramdef>size_t <parameter>length</parameter></paramdef> + <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> + </funcprototype></funcsynopsis> + <literallayout></literallayout> + <para>An extent decommit function conforms to the + <type>extent_decommit_t</type> type and decommits any physical memory + that is backing pages within an extent at given + <parameter>addr</parameter> and <parameter>size</parameter> at + <parameter>offset</parameter> bytes, extending for + <parameter>length</parameter> on behalf of arena + <parameter>arena_ind</parameter>, returning false upon success, in which + case the pages will be committed via the extent commit function before + being reused. If the function returns true, this indicates opt-out from + decommit; the memory remains committed and available for future use, in + which case it will be automatically retained for later reuse.</para> + + <funcsynopsis><funcprototype> + <funcdef>typedef bool <function>(extent_purge_t)</function></funcdef> + <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> + <paramdef>void *<parameter>addr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>size_t <parameter>offset</parameter></paramdef> + <paramdef>size_t <parameter>length</parameter></paramdef> + <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> + </funcprototype></funcsynopsis> + <literallayout></literallayout> + <para>An extent purge function conforms to the + <type>extent_purge_t</type> type and discards physical pages + within the virtual memory mapping associated with an extent at given + <parameter>addr</parameter> and <parameter>size</parameter> at + <parameter>offset</parameter> bytes, extending for + <parameter>length</parameter> on behalf of arena + <parameter>arena_ind</parameter>. A lazy extent purge function (e.g. + implemented via + <function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function>) + can delay purging indefinitely and leave the pages within the purged + virtual memory range in an indeterminite state, whereas a forced extent + purge function immediately purges, and the pages within the virtual + memory range will be zero-filled the next time they are accessed. If + the function returns true, this indicates failure to purge.</para> + + <funcsynopsis><funcprototype> + <funcdef>typedef bool <function>(extent_split_t)</function></funcdef> + <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> + <paramdef>void *<parameter>addr</parameter></paramdef> + <paramdef>size_t <parameter>size</parameter></paramdef> + <paramdef>size_t <parameter>size_a</parameter></paramdef> + <paramdef>size_t <parameter>size_b</parameter></paramdef> + <paramdef>bool <parameter>committed</parameter></paramdef> + <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> + </funcprototype></funcsynopsis> + <literallayout></literallayout> + <para>An extent split function conforms to the + <type>extent_split_t</type> type and optionally splits an extent at + given <parameter>addr</parameter> and <parameter>size</parameter> into + two adjacent extents, the first of <parameter>size_a</parameter> bytes, + and the second of <parameter>size_b</parameter> bytes, operating on + <parameter>committed</parameter>/decommitted memory as indicated, on + behalf of arena <parameter>arena_ind</parameter>, returning false upon + success. If the function returns true, this indicates that the extent + remains unsplit and therefore should continue to be operated on as a + whole.</para> + + <funcsynopsis><funcprototype> + <funcdef>typedef bool <function>(extent_merge_t)</function></funcdef> + <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> + <paramdef>void *<parameter>addr_a</parameter></paramdef> + <paramdef>size_t <parameter>size_a</parameter></paramdef> + <paramdef>void *<parameter>addr_b</parameter></paramdef> + <paramdef>size_t <parameter>size_b</parameter></paramdef> + <paramdef>bool <parameter>committed</parameter></paramdef> + <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> + </funcprototype></funcsynopsis> + <literallayout></literallayout> + <para>An extent merge function conforms to the + <type>extent_merge_t</type> type and optionally merges adjacent extents, + at given <parameter>addr_a</parameter> and <parameter>size_a</parameter> + with given <parameter>addr_b</parameter> and + <parameter>size_b</parameter> into one contiguous extent, operating on + <parameter>committed</parameter>/decommitted memory as indicated, on + behalf of arena <parameter>arena_ind</parameter>, returning false upon + success. If the function returns true, this indicates that the extents + remain distinct mappings and therefore should continue to be operated on + independently.</para> + </listitem> + </varlistentry> + + <varlistentry id="arenas.narenas"> + <term> + <mallctl>arenas.narenas</mallctl> + (<type>unsigned</type>) + <literal>r-</literal> + </term> + <listitem><para>Current limit on number of arenas.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.dirty_decay_ms"> + <term> + <mallctl>arenas.dirty_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>rw</literal> + </term> + <listitem><para>Current default per-arena approximate time in + milliseconds from the creation of a set of unused dirty pages until an + equivalent set of unused dirty pages is purged and/or reused, used to + initialize <link + linkend="arena.i.dirty_decay_ms"><mallctl>arena.<i>.dirty_decay_ms</mallctl></link> + during arena creation. See <link + linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> + for additional information.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.muzzy_decay_ms"> + <term> + <mallctl>arenas.muzzy_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>rw</literal> + </term> + <listitem><para>Current default per-arena approximate time in + milliseconds from the creation of a set of unused muzzy pages until an + equivalent set of unused muzzy pages is purged and/or reused, used to + initialize <link + linkend="arena.i.muzzy_decay_ms"><mallctl>arena.<i>.muzzy_decay_ms</mallctl></link> + during arena creation. See <link + linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> + for additional information.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.quantum"> + <term> + <mallctl>arenas.quantum</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Quantum size.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.page"> + <term> + <mallctl>arenas.page</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Page size.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.tcache_max"> + <term> + <mallctl>arenas.tcache_max</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Maximum thread-cached size class.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.nbins"> + <term> + <mallctl>arenas.nbins</mallctl> + (<type>unsigned</type>) + <literal>r-</literal> + </term> + <listitem><para>Number of bin size classes.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.nhbins"> + <term> + <mallctl>arenas.nhbins</mallctl> + (<type>unsigned</type>) + <literal>r-</literal> + </term> + <listitem><para>Total number of thread cache bin size + classes.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.bin.i.size"> + <term> + <mallctl>arenas.bin.<i>.size</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Maximum size supported by size class.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.bin.i.nregs"> + <term> + <mallctl>arenas.bin.<i>.nregs</mallctl> + (<type>uint32_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Number of regions per slab.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.bin.i.slab_size"> + <term> + <mallctl>arenas.bin.<i>.slab_size</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Number of bytes per slab.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.nlextents"> + <term> + <mallctl>arenas.nlextents</mallctl> + (<type>unsigned</type>) + <literal>r-</literal> + </term> + <listitem><para>Total number of large size classes.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.lextent.i.size"> + <term> + <mallctl>arenas.lextent.<i>.size</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Maximum size supported by this large size + class.</para></listitem> + </varlistentry> + + <varlistentry id="arenas.create"> + <term> + <mallctl>arenas.create</mallctl> + (<type>unsigned</type>, <type>extent_hooks_t *</type>) + <literal>rw</literal> + </term> + <listitem><para>Explicitly create a new arena outside the range of + automatically managed arenas, with optionally specified extent hooks, + and return the new arena index.</para> + + <para>If the amount of space supplied for storing the arena index does + not equal <code language="C">sizeof(<type>unsigned</type>)</code>, no + arena will be created, no data will be written to the space pointed by + <parameter>oldp</parameter>, and <parameter>*oldlenp</parameter> will + be set to 0. + </para></listitem> + </varlistentry> + + <varlistentry id="arenas.lookup"> + <term> + <mallctl>arenas.lookup</mallctl> + (<type>unsigned</type>, <type>void*</type>) + <literal>rw</literal> + </term> + <listitem><para>Index of the arena to which an allocation belongs to.</para></listitem> + </varlistentry> + + <varlistentry id="prof.thread_active_init"> + <term> + <mallctl>prof.thread_active_init</mallctl> + (<type>bool</type>) + <literal>rw</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Control the initial setting for <link + linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> + in newly created threads. See the <link + linkend="opt.prof_thread_active_init"><mallctl>opt.prof_thread_active_init</mallctl></link> + option for additional information.</para></listitem> + </varlistentry> + + <varlistentry id="prof.active"> + <term> + <mallctl>prof.active</mallctl> + (<type>bool</type>) + <literal>rw</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Control whether sampling is currently active. See the + <link + linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link> + option for additional information, as well as the interrelated <link + linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> + mallctl.</para></listitem> + </varlistentry> + + <varlistentry id="prof.dump"> + <term> + <mallctl>prof.dump</mallctl> + (<type>const char *</type>) + <literal>-w</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Dump a memory profile to the specified file, or if NULL + is specified, to a file according to the pattern + <filename><prefix>.<pid>.<seq>.m<mseq>.heap</filename>, + where <literal><prefix></literal> is controlled by the + <link linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> + and <link linkend="prof.prefix"><mallctl>prof.prefix</mallctl></link> + options.</para></listitem> + </varlistentry> + + <varlistentry id="prof.prefix"> + <term> + <mallctl>prof.prefix</mallctl> + (<type>const char *</type>) + <literal>-w</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Set the filename prefix for profile dumps. See + <link + linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> + for the default setting. This can be useful to differentiate profile + dumps such as from forked processes. + </para></listitem> + </varlistentry> + + <varlistentry id="prof.gdump"> + <term> + <mallctl>prof.gdump</mallctl> + (<type>bool</type>) + <literal>rw</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>When enabled, trigger a memory profile dump every time + the total virtual memory exceeds the previous maximum. Profiles are + dumped to files named according to the pattern + <filename><prefix>.<pid>.<seq>.u<useq>.heap</filename>, + where <literal><prefix></literal> is controlled by the <link + linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> and + <link linkend="prof.prefix"><mallctl>prof.prefix</mallctl></link> + options.</para></listitem> + </varlistentry> + + <varlistentry id="prof.reset"> + <term> + <mallctl>prof.reset</mallctl> + (<type>size_t</type>) + <literal>-w</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Reset all memory profile statistics, and optionally + update the sample rate (see <link + linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link> + and <link + linkend="prof.lg_sample"><mallctl>prof.lg_sample</mallctl></link>). + </para></listitem> + </varlistentry> + + <varlistentry id="prof.lg_sample"> + <term> + <mallctl>prof.lg_sample</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Get the current sample rate (see <link + linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link>). + </para></listitem> + </varlistentry> + + <varlistentry id="prof.interval"> + <term> + <mallctl>prof.interval</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-prof</option>] + </term> + <listitem><para>Average number of bytes allocated between + interval-based profile dumps. See the + <link + linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link> + option for additional information.</para></listitem> + </varlistentry> + + <varlistentry id="stats.allocated"> + <term> + <mallctl>stats.allocated</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Total number of bytes allocated by the + application.</para></listitem> + </varlistentry> + + <varlistentry id="stats.active"> + <term> + <mallctl>stats.active</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Total number of bytes in active pages allocated by the + application. This is a multiple of the page size, and greater than or + equal to <link + linkend="stats.allocated"><mallctl>stats.allocated</mallctl></link>. + This does not include <link linkend="stats.arenas.i.pdirty"> + <mallctl>stats.arenas.<i>.pdirty</mallctl></link>, + <link linkend="stats.arenas.i.pmuzzy"> + <mallctl>stats.arenas.<i>.pmuzzy</mallctl></link>, nor pages + entirely devoted to allocator metadata.</para></listitem> + </varlistentry> + + <varlistentry id="stats.metadata"> + <term> + <mallctl>stats.metadata</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Total number of bytes dedicated to metadata, which + comprise base allocations used for bootstrap-sensitive allocator + metadata structures (see <link + linkend="stats.arenas.i.base"><mallctl>stats.arenas.<i>.base</mallctl></link>) + and internal allocations (see <link + linkend="stats.arenas.i.internal"><mallctl>stats.arenas.<i>.internal</mallctl></link>). + Transparent huge page (enabled with <link + linkend="opt.metadata_thp">opt.metadata_thp</link>) usage is not + considered.</para></listitem> + </varlistentry> + + <varlistentry id="stats.metadata_thp"> + <term> + <mallctl>stats.metadata_thp</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of transparent huge pages (THP) used for + metadata. See <link + linkend="stats.metadata"><mallctl>stats.metadata</mallctl></link> and + <link linkend="opt.metadata_thp">opt.metadata_thp</link>) for + details.</para></listitem> + </varlistentry> + + <varlistentry id="stats.resident"> + <term> + <mallctl>stats.resident</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Maximum number of bytes in physically resident data + pages mapped by the allocator, comprising all pages dedicated to + allocator metadata, pages backing active allocations, and unused dirty + pages. This is a maximum rather than precise because pages may not + actually be physically resident if they correspond to demand-zeroed + virtual memory that has not yet been touched. This is a multiple of the + page size, and is larger than <link + linkend="stats.active"><mallctl>stats.active</mallctl></link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.mapped"> + <term> + <mallctl>stats.mapped</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Total number of bytes in active extents mapped by the + allocator. This is larger than <link + linkend="stats.active"><mallctl>stats.active</mallctl></link>. This + does not include inactive extents, even those that contain unused dirty + pages, which means that there is no strict ordering between this and + <link + linkend="stats.resident"><mallctl>stats.resident</mallctl></link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.retained"> + <term> + <mallctl>stats.retained</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Total number of bytes in virtual memory mappings that + were retained rather than being returned to the operating system via + e.g. <citerefentry><refentrytitle>munmap</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> or similar. Retained virtual + memory is typically untouched, decommitted, or purged, so it has no + strongly associated physical memory (see <link + linkend="arena.i.extent_hooks">extent hooks</link> for details). + Retained memory is excluded from mapped memory statistics, e.g. <link + linkend="stats.mapped"><mallctl>stats.mapped</mallctl></link>. + </para></listitem> + </varlistentry> + + <varlistentry id="stats.zero_reallocs"> + <term> + <mallctl>stats.zero_reallocs</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of times that the <function>realloc()</function> + was called with a non-<constant>NULL</constant> pointer argument and a + <constant>0</constant> size argument. This is a fundamentally unsafe + pattern in portable programs; see <link linkend="opt.zero_realloc"> + <mallctl>opt.zero_realloc</mallctl></link> for details. + </para></listitem> + </varlistentry> + + <varlistentry id="stats.background_thread.num_threads"> + <term> + <mallctl>stats.background_thread.num_threads</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para> Number of <link linkend="background_thread">background + threads</link> running currently.</para></listitem> + </varlistentry> + + <varlistentry id="stats.background_thread.num_runs"> + <term> + <mallctl>stats.background_thread.num_runs</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para> Total number of runs from all <link + linkend="background_thread">background threads</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.background_thread.run_interval"> + <term> + <mallctl>stats.background_thread.run_interval</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para> Average run interval in nanoseconds of <link + linkend="background_thread">background threads</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.mutexes.ctl"> + <term> + <mallctl>stats.mutexes.ctl.{counter};</mallctl> + (<type>counter specific type</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>ctl</varname> mutex (global + scope; mallctl related). <mallctl>{counter}</mallctl> is one of the + counters below:</para> + <varlistentry id="mutex_counters"> + <listitem><para><varname>num_ops</varname> (<type>uint64_t</type>): + Total number of lock acquisition operations on this mutex.</para> + + <para><varname>num_spin_acq</varname> (<type>uint64_t</type>): Number + of times the mutex was spin-acquired. When the mutex is currently + locked and cannot be acquired immediately, a short period of + spin-retry within jemalloc will be performed. Acquired through spin + generally means the contention was lightweight and not causing context + switches.</para> + + <para><varname>num_wait</varname> (<type>uint64_t</type>): Number of + times the mutex was wait-acquired, which means the mutex contention + was not solved by spin-retry, and blocking operation was likely + involved in order to acquire the mutex. This event generally implies + higher cost / longer delay, and should be investigated if it happens + often.</para> + + <para><varname>max_wait_time</varname> (<type>uint64_t</type>): + Maximum length of time in nanoseconds spent on a single wait-acquired + lock operation. Note that to avoid profiling overhead on the common + path, this does not consider spin-acquired cases.</para> + + <para><varname>total_wait_time</varname> (<type>uint64_t</type>): + Cumulative time in nanoseconds spent on wait-acquired lock operations. + Similarly, spin-acquired cases are not considered.</para> + + <para><varname>max_num_thds</varname> (<type>uint32_t</type>): Maximum + number of threads waiting on this mutex simultaneously. Similarly, + spin-acquired cases are not considered.</para> + + <para><varname>num_owner_switch</varname> (<type>uint64_t</type>): + Number of times the current mutex owner is different from the previous + one. This event does not generally imply an issue; rather it is an + indicator of how often the protected data are accessed by different + threads. + </para> + </listitem> + </varlistentry> + </listitem> + </varlistentry> + + <varlistentry id="stats.mutexes.background_thread"> + <term> + <mallctl>stats.mutexes.background_thread.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>background_thread</varname> mutex + (global scope; <link + linkend="background_thread"><mallctl>background_thread</mallctl></link> + related). <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.mutexes.prof"> + <term> + <mallctl>stats.mutexes.prof.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>prof</varname> mutex (global + scope; profiling related). <mallctl>{counter}</mallctl> is one of the + counters in <link linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.mutexes.prof_thds_data"> + <term> + <mallctl>stats.mutexes.prof_thds_data.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>prof</varname> threads data mutex + (global scope; profiling related). <mallctl>{counter}</mallctl> is one + of the counters in <link linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.mutexes.prof_dump"> + <term> + <mallctl>stats.mutexes.prof_dump.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>prof</varname> dumping mutex + (global scope; profiling related). <mallctl>{counter}</mallctl> is one + of the counters in <link linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.mutexes.reset"> + <term> + <mallctl>stats.mutexes.reset</mallctl> + (<type>void</type>) <literal>--</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Reset all mutex profile statistics, including global + mutexes, arena mutexes and bin mutexes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.dss"> + <term> + <mallctl>stats.arenas.<i>.dss</mallctl> + (<type>const char *</type>) + <literal>r-</literal> + </term> + <listitem><para>dss (<citerefentry><refentrytitle>sbrk</refentrytitle> + <manvolnum>2</manvolnum></citerefentry>) allocation precedence as + related to <citerefentry><refentrytitle>mmap</refentrytitle> + <manvolnum>2</manvolnum></citerefentry> allocation. See <link + linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for details. + </para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.dirty_decay_ms"> + <term> + <mallctl>stats.arenas.<i>.dirty_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Approximate time in milliseconds from the creation of a + set of unused dirty pages until an equivalent set of unused dirty pages + is purged and/or reused. See <link + linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> + for details.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.muzzy_decay_ms"> + <term> + <mallctl>stats.arenas.<i>.muzzy_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Approximate time in milliseconds from the creation of a + set of unused muzzy pages until an equivalent set of unused muzzy pages + is purged and/or reused. See <link + linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> + for details.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.nthreads"> + <term> + <mallctl>stats.arenas.<i>.nthreads</mallctl> + (<type>unsigned</type>) + <literal>r-</literal> + </term> + <listitem><para>Number of threads currently assigned to + arena.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.uptime"> + <term> + <mallctl>stats.arenas.<i>.uptime</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Time elapsed (in nanoseconds) since the arena was + created. If <i> equals <constant>0</constant> or + <constant>MALLCTL_ARENAS_ALL</constant>, this is the uptime since malloc + initialization.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.pactive"> + <term> + <mallctl>stats.arenas.<i>.pactive</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Number of pages in active extents.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.pdirty"> + <term> + <mallctl>stats.arenas.<i>.pdirty</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Number of pages within unused extents that are + potentially dirty, and for which <function>madvise()</function> or + similar has not been called. See <link + linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> + for a description of dirty pages.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.pmuzzy"> + <term> + <mallctl>stats.arenas.<i>.pmuzzy</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Number of pages within unused extents that are muzzy. + See <link + linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> + for a description of muzzy pages.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mapped"> + <term> + <mallctl>stats.arenas.<i>.mapped</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of mapped bytes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.retained"> + <term> + <mallctl>stats.arenas.<i>.retained</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of retained bytes. See <link + linkend="stats.retained"><mallctl>stats.retained</mallctl></link> for + details.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.extent_avail"> + <term> + <mallctl>stats.arenas.<i>.extent_avail</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of allocated (but unused) extent structs in this + arena.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.base"> + <term> + <mallctl>stats.arenas.<i>.base</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para> + Number of bytes dedicated to bootstrap-sensitive allocator metadata + structures.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.internal"> + <term> + <mallctl>stats.arenas.<i>.internal</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of bytes dedicated to internal allocations. + Internal allocations differ from application-originated allocations in + that they are for internal use, and that they are omitted from heap + profiles.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.metadata_thp"> + <term> + <mallctl>stats.arenas.<i>.metadata_thp</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of transparent huge pages (THP) used for + metadata. See <link linkend="opt.metadata_thp">opt.metadata_thp</link> + for details.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.resident"> + <term> + <mallctl>stats.arenas.<i>.resident</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Maximum number of bytes in physically resident data + pages mapped by the arena, comprising all pages dedicated to allocator + metadata, pages backing active allocations, and unused dirty pages. + This is a maximum rather than precise because pages may not actually be + physically resident if they correspond to demand-zeroed virtual memory + that has not yet been touched. This is a multiple of the page + size.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.dirty_npurge"> + <term> + <mallctl>stats.arenas.<i>.dirty_npurge</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of dirty page purge sweeps performed. + </para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.dirty_nmadvise"> + <term> + <mallctl>stats.arenas.<i>.dirty_nmadvise</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of <function>madvise()</function> or similar + calls made to purge dirty pages.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.dirty_purged"> + <term> + <mallctl>stats.arenas.<i>.dirty_purged</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of dirty pages purged.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.muzzy_npurge"> + <term> + <mallctl>stats.arenas.<i>.muzzy_npurge</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of muzzy page purge sweeps performed. + </para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.muzzy_nmadvise"> + <term> + <mallctl>stats.arenas.<i>.muzzy_nmadvise</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of <function>madvise()</function> or similar + calls made to purge muzzy pages.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.muzzy_purged"> + <term> + <mallctl>stats.arenas.<i>.muzzy_purged</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of muzzy pages purged.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.small.allocated"> + <term> + <mallctl>stats.arenas.<i>.small.allocated</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of bytes currently allocated by small objects. + </para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.small.nmalloc"> + <term> + <mallctl>stats.arenas.<i>.small.nmalloc</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times a small allocation was + requested from the arena's bins, whether to fill the relevant tcache if + <link linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is + enabled, or to directly satisfy an allocation request + otherwise.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.small.ndalloc"> + <term> + <mallctl>stats.arenas.<i>.small.ndalloc</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times a small allocation was + returned to the arena's bins, whether to flush the relevant tcache if + <link linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is + enabled, or to directly deallocate an allocation + otherwise.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.small.nrequests"> + <term> + <mallctl>stats.arenas.<i>.small.nrequests</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of allocation requests satisfied by + all bin size classes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.small.nfills"> + <term> + <mallctl>stats.arenas.<i>.small.nfills</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of tcache fills by all small size + classes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.small.nflushes"> + <term> + <mallctl>stats.arenas.<i>.small.nflushes</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of tcache flushes by all small size + classes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.large.allocated"> + <term> + <mallctl>stats.arenas.<i>.large.allocated</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Number of bytes currently allocated by large objects. + </para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.large.nmalloc"> + <term> + <mallctl>stats.arenas.<i>.large.nmalloc</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times a large extent was allocated + from the arena, whether to fill the relevant tcache if <link + linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled and + the size class is within the range being cached, or to directly satisfy + an allocation request otherwise.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.large.ndalloc"> + <term> + <mallctl>stats.arenas.<i>.large.ndalloc</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times a large extent was returned + to the arena, whether to flush the relevant tcache if <link + linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled and + the size class is within the range being cached, or to directly + deallocate an allocation otherwise.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.large.nrequests"> + <term> + <mallctl>stats.arenas.<i>.large.nrequests</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of allocation requests satisfied by + all large size classes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.large.nfills"> + <term> + <mallctl>stats.arenas.<i>.large.nfills</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of tcache fills by all large size + classes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.large.nflushes"> + <term> + <mallctl>stats.arenas.<i>.large.nflushes</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of tcache flushes by all large size + classes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.nmalloc"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.nmalloc</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times a bin region of the + corresponding size class was allocated from the arena, whether to fill + the relevant tcache if <link + linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled, or + to directly satisfy an allocation request otherwise.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.ndalloc"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.ndalloc</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times a bin region of the + corresponding size class was returned to the arena, whether to flush the + relevant tcache if <link + linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled, or + to directly deallocate an allocation otherwise.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.nrequests"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.nrequests</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of allocation requests satisfied by + bin regions of the corresponding size class.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.curregs"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.curregs</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Current number of regions for this size + class.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.nfills"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.nfills</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Cumulative number of tcache fills.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.nflushes"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.nflushes</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + </term> + <listitem><para>Cumulative number of tcache flushes.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.nslabs"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.nslabs</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of slabs created.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.nreslabs"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.nreslabs</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times the current slab from which + to allocate changed.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.j.curslabs"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.curslabs</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Current number of slabs.</para></listitem> + </varlistentry> + + + <varlistentry id="stats.arenas.i.bins.j.nonfull_slabs"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.nonfull_slabs</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Current number of nonfull slabs.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.bins.mutex"> + <term> + <mallctl>stats.arenas.<i>.bins.<j>.mutex.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on + <varname>arena.<i>.bins.<j></varname> mutex (arena bin + scope; bin operation related). <mallctl>{counter}</mallctl> is one of + the counters in <link linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.extents.n"> + <term> + <mallctl>stats.arenas.<i>.extents.<j>.n{extent_type}</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para> Number of extents of the given type in this arena in + the bucket corresponding to page size index <j>. The extent type + is one of dirty, muzzy, or retained.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.extents.bytes"> + <term> + <mallctl>stats.arenas.<i>.extents.<j>.{extent_type}_bytes</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para> Sum of the bytes managed by extents of the given type + in this arena in the bucket corresponding to page size index <j>. + The extent type is one of dirty, muzzy, or retained.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.lextents.j.nmalloc"> + <term> + <mallctl>stats.arenas.<i>.lextents.<j>.nmalloc</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times a large extent of the + corresponding size class was allocated from the arena, whether to fill + the relevant tcache if <link + linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled and + the size class is within the range being cached, or to directly satisfy + an allocation request otherwise.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.lextents.j.ndalloc"> + <term> + <mallctl>stats.arenas.<i>.lextents.<j>.ndalloc</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of times a large extent of the + corresponding size class was returned to the arena, whether to flush the + relevant tcache if <link + linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled and + the size class is within the range being cached, or to directly + deallocate an allocation otherwise.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.lextents.j.nrequests"> + <term> + <mallctl>stats.arenas.<i>.lextents.<j>.nrequests</mallctl> + (<type>uint64_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Cumulative number of allocation requests satisfied by + large extents of the corresponding size class.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.lextents.j.curlextents"> + <term> + <mallctl>stats.arenas.<i>.lextents.<j>.curlextents</mallctl> + (<type>size_t</type>) + <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Current number of large allocations for this size class. + </para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.large"> + <term> + <mallctl>stats.arenas.<i>.mutexes.large.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>arena.<i>.large</varname> + mutex (arena scope; large allocation related). + <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.extent_avail"> + <term> + <mallctl>stats.arenas.<i>.mutexes.extent_avail.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>arena.<i>.extent_avail + </varname> mutex (arena scope; extent avail related). + <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.extents_dirty"> + <term> + <mallctl>stats.arenas.<i>.mutexes.extents_dirty.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>arena.<i>.extents_dirty + </varname> mutex (arena scope; dirty extents related). + <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.extents_muzzy"> + <term> + <mallctl>stats.arenas.<i>.mutexes.extents_muzzy.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>arena.<i>.extents_muzzy + </varname> mutex (arena scope; muzzy extents related). + <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.extents_retained"> + <term> + <mallctl>stats.arenas.<i>.mutexes.extents_retained.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>arena.<i>.extents_retained + </varname> mutex (arena scope; retained extents related). + <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.decay_dirty"> + <term> + <mallctl>stats.arenas.<i>.mutexes.decay_dirty.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>arena.<i>.decay_dirty + </varname> mutex (arena scope; decay for dirty pages related). + <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.decay_muzzy"> + <term> + <mallctl>stats.arenas.<i>.mutexes.decay_muzzy.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>arena.<i>.decay_muzzy + </varname> mutex (arena scope; decay for muzzy pages related). + <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.base"> + <term> + <mallctl>stats.arenas.<i>.mutexes.base.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on <varname>arena.<i>.base</varname> + mutex (arena scope; base allocator related). + <mallctl>{counter}</mallctl> is one of the counters in <link + linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + <varlistentry id="stats.arenas.i.mutexes.tcache_list"> + <term> + <mallctl>stats.arenas.<i>.mutexes.tcache_list.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> + [<option>--enable-stats</option>] + </term> + <listitem><para>Statistics on + <varname>arena.<i>.tcache_list</varname> mutex (arena scope; + tcache to arena association related). This mutex is expected to be + accessed less often. <mallctl>{counter}</mallctl> is one of the + counters in <link linkend="mutex_counters">mutex profiling + counters</link>.</para></listitem> + </varlistentry> + + </variablelist> + </refsect1> + <refsect1 id="heap_profile_format"> + <title>HEAP PROFILE FORMAT</title> + <para>Although the heap profiling functionality was originally designed to + be compatible with the + <command>pprof</command> command that is developed as part of the <ulink + url="http://code.google.com/p/gperftools/">gperftools + package</ulink>, the addition of per thread heap profiling functionality + required a different heap profile format. The <command>jeprof</command> + command is derived from <command>pprof</command>, with enhancements to + support the heap profile format described here.</para> + + <para>In the following hypothetical heap profile, <constant>[...]</constant> + indicates elision for the sake of compactness. <programlisting><![CDATA[ +heap_v2/524288 + t*: 28106: 56637512 [0: 0] + [...] + t3: 352: 16777344 [0: 0] + [...] + t99: 17754: 29341640 [0: 0] + [...] +@ 0x5f86da8 0x5f5a1dc [...] 0x29e4d4e 0xa200316 0xabb2988 [...] + t*: 13: 6688 [0: 0] + t3: 12: 6496 [0: 0] + t99: 1: 192 [0: 0] +[...] + +MAPPED_LIBRARIES: +[...]]]></programlisting> The following matches the above heap profile, but most +tokens are replaced with <constant><description></constant> to indicate +descriptions of the corresponding fields. <programlisting><![CDATA[ +<heap_profile_format_version>/<mean_sample_interval> + <aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] + [...] + <thread_3_aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] + [...] + <thread_99_aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] + [...] +@ <top_frame> <frame> [...] <frame> <frame> <frame> [...] + <backtrace_aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] + <backtrace_thread_3>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] + <backtrace_thread_99>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] +[...] + +MAPPED_LIBRARIES: +</proc/<pid>/maps>]]></programlisting></para> + </refsect1> + + <refsect1 id="debugging_malloc_problems"> + <title>DEBUGGING MALLOC PROBLEMS</title> + <para>When debugging, it is a good idea to configure/build jemalloc with + the <option>--enable-debug</option> and <option>--enable-fill</option> + options, and recompile the program with suitable options and symbols for + debugger support. When so configured, jemalloc incorporates a wide variety + of run-time assertions that catch application errors such as double-free, + write-after-free, etc.</para> + + <para>Programs often accidentally depend on <quote>uninitialized</quote> + memory actually being filled with zero bytes. Junk filling + (see the <link linkend="opt.junk"><mallctl>opt.junk</mallctl></link> + option) tends to expose such bugs in the form of obviously incorrect + results and/or coredumps. Conversely, zero + filling (see the <link + linkend="opt.zero"><mallctl>opt.zero</mallctl></link> option) eliminates + the symptoms of such bugs. Between these two options, it is usually + possible to quickly detect, diagnose, and eliminate such bugs.</para> + + <para>This implementation does not provide much detail about the problems + it detects, because the performance impact for storing such information + would be prohibitive.</para> + </refsect1> + <refsect1 id="diagnostic_messages"> + <title>DIAGNOSTIC MESSAGES</title> + <para>If any of the memory allocation/deallocation functions detect an + error or warning condition, a message will be printed to file descriptor + <constant>STDERR_FILENO</constant>. Errors will result in the process + dumping core. If the <link + linkend="opt.abort"><mallctl>opt.abort</mallctl></link> option is set, most + warnings are treated as errors.</para> + + <para>The <varname>malloc_message</varname> variable allows the programmer + to override the function which emits the text strings forming the errors + and warnings if for some reason the <constant>STDERR_FILENO</constant> file + descriptor is not suitable for this. + <function>malloc_message()</function> takes the + <parameter>cbopaque</parameter> pointer argument that is + <constant>NULL</constant> unless overridden by the arguments in a call to + <function>malloc_stats_print()</function>, followed by a string + pointer. Please note that doing anything which tries to allocate memory in + this function is likely to result in a crash or deadlock.</para> + + <para>All messages are prefixed by + <quote><computeroutput><jemalloc>: </computeroutput></quote>.</para> + </refsect1> + <refsect1 id="return_values"> + <title>RETURN VALUES</title> + <refsect2> + <title>Standard API</title> + <para>The <function>malloc()</function> and + <function>calloc()</function> functions return a pointer to the + allocated memory if successful; otherwise a <constant>NULL</constant> + pointer is returned and <varname>errno</varname> is set to + <errorname>ENOMEM</errorname>.</para> + + <para>The <function>posix_memalign()</function> function + returns the value 0 if successful; otherwise it returns an error value. + The <function>posix_memalign()</function> function will fail + if: + <variablelist> + <varlistentry> + <term><errorname>EINVAL</errorname></term> + + <listitem><para>The <parameter>alignment</parameter> parameter is + not a power of 2 at least as large as + <code language="C">sizeof(<type>void *</type>)</code>. + </para></listitem> + </varlistentry> + <varlistentry> + <term><errorname>ENOMEM</errorname></term> + + <listitem><para>Memory allocation error.</para></listitem> + </varlistentry> + </variablelist> + </para> + + <para>The <function>aligned_alloc()</function> function returns + a pointer to the allocated memory if successful; otherwise a + <constant>NULL</constant> pointer is returned and + <varname>errno</varname> is set. The + <function>aligned_alloc()</function> function will fail if: + <variablelist> + <varlistentry> + <term><errorname>EINVAL</errorname></term> + + <listitem><para>The <parameter>alignment</parameter> parameter is + not a power of 2. + </para></listitem> + </varlistentry> + <varlistentry> + <term><errorname>ENOMEM</errorname></term> + + <listitem><para>Memory allocation error.</para></listitem> + </varlistentry> + </variablelist> + </para> + + <para>The <function>realloc()</function> function returns a + pointer, possibly identical to <parameter>ptr</parameter>, to the + allocated memory if successful; otherwise a <constant>NULL</constant> + pointer is returned, and <varname>errno</varname> is set to + <errorname>ENOMEM</errorname> if the error was the result of an + allocation failure. The <function>realloc()</function> + function always leaves the original buffer intact when an error occurs. + </para> + + <para>The <function>free()</function> function returns no + value.</para> + </refsect2> + <refsect2> + <title>Non-standard API</title> + <para>The <function>mallocx()</function> and + <function>rallocx()</function> functions return a pointer to + the allocated memory if successful; otherwise a <constant>NULL</constant> + pointer is returned to indicate insufficient contiguous memory was + available to service the allocation request. </para> + + <para>The <function>xallocx()</function> function returns the + real size of the resulting resized allocation pointed to by + <parameter>ptr</parameter>, which is a value less than + <parameter>size</parameter> if the allocation could not be adequately + grown in place. </para> + + <para>The <function>sallocx()</function> function returns the + real size of the allocation pointed to by <parameter>ptr</parameter>. + </para> + + <para>The <function>nallocx()</function> returns the real size + that would result from a successful equivalent + <function>mallocx()</function> function call, or zero if + insufficient memory is available to perform the size computation. </para> + + <para>The <function>mallctl()</function>, + <function>mallctlnametomib()</function>, and + <function>mallctlbymib()</function> functions return 0 on + success; otherwise they return an error value. The functions will fail + if: + <variablelist> + <varlistentry> + <term><errorname>EINVAL</errorname></term> + + <listitem><para><parameter>newp</parameter> is not + <constant>NULL</constant>, and <parameter>newlen</parameter> is too + large or too small. Alternatively, <parameter>*oldlenp</parameter> + is too large or too small; when it happens, except for a very few + cases explicitly documented otherwise, as much data as possible + are read despite the error, with the amount of data read being + recorded in <parameter>*oldlenp</parameter>.</para></listitem> + </varlistentry> + <varlistentry> + <term><errorname>ENOENT</errorname></term> + + <listitem><para><parameter>name</parameter> or + <parameter>mib</parameter> specifies an unknown/invalid + value.</para></listitem> + </varlistentry> + <varlistentry> + <term><errorname>EPERM</errorname></term> + + <listitem><para>Attempt to read or write void value, or attempt to + write read-only value.</para></listitem> + </varlistentry> + <varlistentry> + <term><errorname>EAGAIN</errorname></term> + + <listitem><para>A memory allocation failure + occurred.</para></listitem> + </varlistentry> + <varlistentry> + <term><errorname>EFAULT</errorname></term> + + <listitem><para>An interface with side effects failed in some way + not directly related to <function>mallctl*()</function> + read/write processing.</para></listitem> + </varlistentry> + </variablelist> + </para> + + <para>The <function>malloc_usable_size()</function> function + returns the usable size of the allocation pointed to by + <parameter>ptr</parameter>. </para> + </refsect2> + </refsect1> + <refsect1 id="environment"> + <title>ENVIRONMENT</title> + <para>The following environment variable affects the execution of the + allocation functions: + <variablelist> + <varlistentry> + <term><envar>MALLOC_CONF</envar></term> + + <listitem><para>If the environment variable + <envar>MALLOC_CONF</envar> is set, the characters it contains + will be interpreted as options.</para></listitem> + </varlistentry> + </variablelist> + </para> + </refsect1> + <refsect1 id="examples"> + <title>EXAMPLES</title> + <para>To dump core whenever a problem occurs: + <screen>ln -s 'abort:true' /etc/malloc.conf</screen> + </para> + <para>To specify in the source that only one arena should be automatically + created: + <programlisting language="C"><![CDATA[ +malloc_conf = "narenas:1";]]></programlisting></para> + </refsect1> + <refsect1 id="see_also"> + <title>SEE ALSO</title> + <para><citerefentry><refentrytitle>madvise</refentrytitle> + <manvolnum>2</manvolnum></citerefentry>, + <citerefentry><refentrytitle>mmap</refentrytitle> + <manvolnum>2</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sbrk</refentrytitle> + <manvolnum>2</manvolnum></citerefentry>, + <citerefentry><refentrytitle>utrace</refentrytitle> + <manvolnum>2</manvolnum></citerefentry>, + <citerefentry><refentrytitle>alloca</refentrytitle> + <manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>atexit</refentrytitle> + <manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>getpagesize</refentrytitle> + <manvolnum>3</manvolnum></citerefentry></para> + </refsect1> + <refsect1 id="standards"> + <title>STANDARDS</title> + <para>The <function>malloc()</function>, + <function>calloc()</function>, + <function>realloc()</function>, and + <function>free()</function> functions conform to ISO/IEC + 9899:1990 (<quote>ISO C90</quote>).</para> + + <para>The <function>posix_memalign()</function> function conforms + to IEEE Std 1003.1-2001 (<quote>POSIX.1</quote>).</para> + </refsect1> +</refentry> |