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Diffstat (limited to 'src/backend/utils/mmgr/mcxt.c')
| -rw-r--r-- | src/backend/utils/mmgr/mcxt.c | 1341 |
1 files changed, 1341 insertions, 0 deletions
diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c new file mode 100644 index 0000000..a5f31e2 --- /dev/null +++ b/src/backend/utils/mmgr/mcxt.c @@ -0,0 +1,1341 @@ +/*------------------------------------------------------------------------- + * + * mcxt.c + * POSTGRES memory context management code. + * + * This module handles context management operations that are independent + * of the particular kind of context being operated on. It calls + * context-type-specific operations via the function pointers in a + * context's MemoryContextMethods struct. + * + * + * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/backend/utils/mmgr/mcxt.c + * + *------------------------------------------------------------------------- + */ + +#include "postgres.h" + +#include "mb/pg_wchar.h" +#include "miscadmin.h" +#include "storage/proc.h" +#include "storage/procarray.h" +#include "storage/procsignal.h" +#include "utils/fmgrprotos.h" +#include "utils/memdebug.h" +#include "utils/memutils.h" + + +/***************************************************************************** + * GLOBAL MEMORY * + *****************************************************************************/ + +/* + * CurrentMemoryContext + * Default memory context for allocations. + */ +MemoryContext CurrentMemoryContext = NULL; + +/* + * Standard top-level contexts. For a description of the purpose of each + * of these contexts, refer to src/backend/utils/mmgr/README + */ +MemoryContext TopMemoryContext = NULL; +MemoryContext ErrorContext = NULL; +MemoryContext PostmasterContext = NULL; +MemoryContext CacheMemoryContext = NULL; +MemoryContext MessageContext = NULL; +MemoryContext TopTransactionContext = NULL; +MemoryContext CurTransactionContext = NULL; + +/* This is a transient link to the active portal's memory context: */ +MemoryContext PortalContext = NULL; + +static void MemoryContextCallResetCallbacks(MemoryContext context); +static void MemoryContextStatsInternal(MemoryContext context, int level, + bool print, int max_children, + MemoryContextCounters *totals, + bool print_to_stderr); +static void MemoryContextStatsPrint(MemoryContext context, void *passthru, + const char *stats_string, + bool print_to_stderr); + +/* + * You should not do memory allocations within a critical section, because + * an out-of-memory error will be escalated to a PANIC. To enforce that + * rule, the allocation functions Assert that. + */ +#define AssertNotInCriticalSection(context) \ + Assert(CritSectionCount == 0 || (context)->allowInCritSection) + + +/***************************************************************************** + * EXPORTED ROUTINES * + *****************************************************************************/ + + +/* + * MemoryContextInit + * Start up the memory-context subsystem. + * + * This must be called before creating contexts or allocating memory in + * contexts. TopMemoryContext and ErrorContext are initialized here; + * other contexts must be created afterwards. + * + * In normal multi-backend operation, this is called once during + * postmaster startup, and not at all by individual backend startup + * (since the backends inherit an already-initialized context subsystem + * by virtue of being forked off the postmaster). But in an EXEC_BACKEND + * build, each process must do this for itself. + * + * In a standalone backend this must be called during backend startup. + */ +void +MemoryContextInit(void) +{ + AssertState(TopMemoryContext == NULL); + + /* + * First, initialize TopMemoryContext, which is the parent of all others. + */ + TopMemoryContext = AllocSetContextCreate((MemoryContext) NULL, + "TopMemoryContext", + ALLOCSET_DEFAULT_SIZES); + + /* + * Not having any other place to point CurrentMemoryContext, make it point + * to TopMemoryContext. Caller should change this soon! + */ + CurrentMemoryContext = TopMemoryContext; + + /* + * Initialize ErrorContext as an AllocSetContext with slow growth rate --- + * we don't really expect much to be allocated in it. More to the point, + * require it to contain at least 8K at all times. This is the only case + * where retained memory in a context is *essential* --- we want to be + * sure ErrorContext still has some memory even if we've run out + * elsewhere! Also, allow allocations in ErrorContext within a critical + * section. Otherwise a PANIC will cause an assertion failure in the error + * reporting code, before printing out the real cause of the failure. + * + * This should be the last step in this function, as elog.c assumes memory + * management works once ErrorContext is non-null. + */ + ErrorContext = AllocSetContextCreate(TopMemoryContext, + "ErrorContext", + 8 * 1024, + 8 * 1024, + 8 * 1024); + MemoryContextAllowInCriticalSection(ErrorContext, true); +} + +/* + * MemoryContextReset + * Release all space allocated within a context and delete all its + * descendant contexts (but not the named context itself). + */ +void +MemoryContextReset(MemoryContext context) +{ + AssertArg(MemoryContextIsValid(context)); + + /* save a function call in common case where there are no children */ + if (context->firstchild != NULL) + MemoryContextDeleteChildren(context); + + /* save a function call if no pallocs since startup or last reset */ + if (!context->isReset) + MemoryContextResetOnly(context); +} + +/* + * MemoryContextResetOnly + * Release all space allocated within a context. + * Nothing is done to the context's descendant contexts. + */ +void +MemoryContextResetOnly(MemoryContext context) +{ + AssertArg(MemoryContextIsValid(context)); + + /* Nothing to do if no pallocs since startup or last reset */ + if (!context->isReset) + { + MemoryContextCallResetCallbacks(context); + + /* + * If context->ident points into the context's memory, it will become + * a dangling pointer. We could prevent that by setting it to NULL + * here, but that would break valid coding patterns that keep the + * ident elsewhere, e.g. in a parent context. Another idea is to use + * MemoryContextContains(), but we don't require ident strings to be + * in separately-palloc'd chunks, so that risks false positives. So + * for now we assume the programmer got it right. + */ + + context->methods->reset(context); + context->isReset = true; + VALGRIND_DESTROY_MEMPOOL(context); + VALGRIND_CREATE_MEMPOOL(context, 0, false); + } +} + +/* + * MemoryContextResetChildren + * Release all space allocated within a context's descendants, + * but don't delete the contexts themselves. The named context + * itself is not touched. + */ +void +MemoryContextResetChildren(MemoryContext context) +{ + MemoryContext child; + + AssertArg(MemoryContextIsValid(context)); + + for (child = context->firstchild; child != NULL; child = child->nextchild) + { + MemoryContextResetChildren(child); + MemoryContextResetOnly(child); + } +} + +/* + * MemoryContextDelete + * Delete a context and its descendants, and release all space + * allocated therein. + * + * The type-specific delete routine removes all storage for the context, + * but we have to recurse to handle the children. + * We must also delink the context from its parent, if it has one. + */ +void +MemoryContextDelete(MemoryContext context) +{ + AssertArg(MemoryContextIsValid(context)); + /* We had better not be deleting TopMemoryContext ... */ + Assert(context != TopMemoryContext); + /* And not CurrentMemoryContext, either */ + Assert(context != CurrentMemoryContext); + + /* save a function call in common case where there are no children */ + if (context->firstchild != NULL) + MemoryContextDeleteChildren(context); + + /* + * It's not entirely clear whether 'tis better to do this before or after + * delinking the context; but an error in a callback will likely result in + * leaking the whole context (if it's not a root context) if we do it + * after, so let's do it before. + */ + MemoryContextCallResetCallbacks(context); + + /* + * We delink the context from its parent before deleting it, so that if + * there's an error we won't have deleted/busted contexts still attached + * to the context tree. Better a leak than a crash. + */ + MemoryContextSetParent(context, NULL); + + /* + * Also reset the context's ident pointer, in case it points into the + * context. This would only matter if someone tries to get stats on the + * (already unlinked) context, which is unlikely, but let's be safe. + */ + context->ident = NULL; + + context->methods->delete_context(context); + + VALGRIND_DESTROY_MEMPOOL(context); +} + +/* + * MemoryContextDeleteChildren + * Delete all the descendants of the named context and release all + * space allocated therein. The named context itself is not touched. + */ +void +MemoryContextDeleteChildren(MemoryContext context) +{ + AssertArg(MemoryContextIsValid(context)); + + /* + * MemoryContextDelete will delink the child from me, so just iterate as + * long as there is a child. + */ + while (context->firstchild != NULL) + MemoryContextDelete(context->firstchild); +} + +/* + * MemoryContextRegisterResetCallback + * Register a function to be called before next context reset/delete. + * Such callbacks will be called in reverse order of registration. + * + * The caller is responsible for allocating a MemoryContextCallback struct + * to hold the info about this callback request, and for filling in the + * "func" and "arg" fields in the struct to show what function to call with + * what argument. Typically the callback struct should be allocated within + * the specified context, since that means it will automatically be freed + * when no longer needed. + * + * There is no API for deregistering a callback once registered. If you + * want it to not do anything anymore, adjust the state pointed to by its + * "arg" to indicate that. + */ +void +MemoryContextRegisterResetCallback(MemoryContext context, + MemoryContextCallback *cb) +{ + AssertArg(MemoryContextIsValid(context)); + + /* Push onto head so this will be called before older registrants. */ + cb->next = context->reset_cbs; + context->reset_cbs = cb; + /* Mark the context as non-reset (it probably is already). */ + context->isReset = false; +} + +/* + * MemoryContextCallResetCallbacks + * Internal function to call all registered callbacks for context. + */ +static void +MemoryContextCallResetCallbacks(MemoryContext context) +{ + MemoryContextCallback *cb; + + /* + * We pop each callback from the list before calling. That way, if an + * error occurs inside the callback, we won't try to call it a second time + * in the likely event that we reset or delete the context later. + */ + while ((cb = context->reset_cbs) != NULL) + { + context->reset_cbs = cb->next; + cb->func(cb->arg); + } +} + +/* + * MemoryContextSetIdentifier + * Set the identifier string for a memory context. + * + * An identifier can be provided to help distinguish among different contexts + * of the same kind in memory context stats dumps. The identifier string + * must live at least as long as the context it is for; typically it is + * allocated inside that context, so that it automatically goes away on + * context deletion. Pass id = NULL to forget any old identifier. + */ +void +MemoryContextSetIdentifier(MemoryContext context, const char *id) +{ + AssertArg(MemoryContextIsValid(context)); + context->ident = id; +} + +/* + * MemoryContextSetParent + * Change a context to belong to a new parent (or no parent). + * + * We provide this as an API function because it is sometimes useful to + * change a context's lifespan after creation. For example, a context + * might be created underneath a transient context, filled with data, + * and then reparented underneath CacheMemoryContext to make it long-lived. + * In this way no special effort is needed to get rid of the context in case + * a failure occurs before its contents are completely set up. + * + * Callers often assume that this function cannot fail, so don't put any + * elog(ERROR) calls in it. + * + * A possible caller error is to reparent a context under itself, creating + * a loop in the context graph. We assert here that context != new_parent, + * but checking for multi-level loops seems more trouble than it's worth. + */ +void +MemoryContextSetParent(MemoryContext context, MemoryContext new_parent) +{ + AssertArg(MemoryContextIsValid(context)); + AssertArg(context != new_parent); + + /* Fast path if it's got correct parent already */ + if (new_parent == context->parent) + return; + + /* Delink from existing parent, if any */ + if (context->parent) + { + MemoryContext parent = context->parent; + + if (context->prevchild != NULL) + context->prevchild->nextchild = context->nextchild; + else + { + Assert(parent->firstchild == context); + parent->firstchild = context->nextchild; + } + + if (context->nextchild != NULL) + context->nextchild->prevchild = context->prevchild; + } + + /* And relink */ + if (new_parent) + { + AssertArg(MemoryContextIsValid(new_parent)); + context->parent = new_parent; + context->prevchild = NULL; + context->nextchild = new_parent->firstchild; + if (new_parent->firstchild != NULL) + new_parent->firstchild->prevchild = context; + new_parent->firstchild = context; + } + else + { + context->parent = NULL; + context->prevchild = NULL; + context->nextchild = NULL; + } +} + +/* + * MemoryContextAllowInCriticalSection + * Allow/disallow allocations in this memory context within a critical + * section. + * + * Normally, memory allocations are not allowed within a critical section, + * because a failure would lead to PANIC. There are a few exceptions to + * that, like allocations related to debugging code that is not supposed to + * be enabled in production. This function can be used to exempt specific + * memory contexts from the assertion in palloc(). + */ +void +MemoryContextAllowInCriticalSection(MemoryContext context, bool allow) +{ + AssertArg(MemoryContextIsValid(context)); + + context->allowInCritSection = allow; +} + +/* + * GetMemoryChunkSpace + * Given a currently-allocated chunk, determine the total space + * it occupies (including all memory-allocation overhead). + * + * This is useful for measuring the total space occupied by a set of + * allocated chunks. + */ +Size +GetMemoryChunkSpace(void *pointer) +{ + MemoryContext context = GetMemoryChunkContext(pointer); + + return context->methods->get_chunk_space(context, pointer); +} + +/* + * MemoryContextGetParent + * Get the parent context (if any) of the specified context + */ +MemoryContext +MemoryContextGetParent(MemoryContext context) +{ + AssertArg(MemoryContextIsValid(context)); + + return context->parent; +} + +/* + * MemoryContextIsEmpty + * Is a memory context empty of any allocated space? + */ +bool +MemoryContextIsEmpty(MemoryContext context) +{ + AssertArg(MemoryContextIsValid(context)); + + /* + * For now, we consider a memory context nonempty if it has any children; + * perhaps this should be changed later. + */ + if (context->firstchild != NULL) + return false; + /* Otherwise use the type-specific inquiry */ + return context->methods->is_empty(context); +} + +/* + * Find the memory allocated to blocks for this memory context. If recurse is + * true, also include children. + */ +Size +MemoryContextMemAllocated(MemoryContext context, bool recurse) +{ + Size total = context->mem_allocated; + + AssertArg(MemoryContextIsValid(context)); + + if (recurse) + { + MemoryContext child; + + for (child = context->firstchild; + child != NULL; + child = child->nextchild) + total += MemoryContextMemAllocated(child, true); + } + + return total; +} + +/* + * MemoryContextStats + * Print statistics about the named context and all its descendants. + * + * This is just a debugging utility, so it's not very fancy. However, we do + * make some effort to summarize when the output would otherwise be very long. + * The statistics are sent to stderr. + */ +void +MemoryContextStats(MemoryContext context) +{ + /* A hard-wired limit on the number of children is usually good enough */ + MemoryContextStatsDetail(context, 100, true); +} + +/* + * MemoryContextStatsDetail + * + * Entry point for use if you want to vary the number of child contexts shown. + * + * If print_to_stderr is true, print statistics about the memory contexts + * with fprintf(stderr), otherwise use ereport(). + */ +void +MemoryContextStatsDetail(MemoryContext context, int max_children, + bool print_to_stderr) +{ + MemoryContextCounters grand_totals; + + memset(&grand_totals, 0, sizeof(grand_totals)); + + MemoryContextStatsInternal(context, 0, true, max_children, &grand_totals, print_to_stderr); + + if (print_to_stderr) + fprintf(stderr, + "Grand total: %zu bytes in %zd blocks; %zu free (%zd chunks); %zu used\n", + grand_totals.totalspace, grand_totals.nblocks, + grand_totals.freespace, grand_totals.freechunks, + grand_totals.totalspace - grand_totals.freespace); + else + + /* + * Use LOG_SERVER_ONLY to prevent the memory contexts from being sent + * to the connected client. + * + * We don't buffer the information about all memory contexts in a + * backend into StringInfo and log it as one message. Otherwise which + * may require the buffer to be enlarged very much and lead to OOM + * error since there can be a large number of memory contexts in a + * backend. Instead, we log one message per memory context. + */ + ereport(LOG_SERVER_ONLY, + (errhidestmt(true), + errhidecontext(true), + errmsg_internal("Grand total: %zu bytes in %zd blocks; %zu free (%zd chunks); %zu used", + grand_totals.totalspace, grand_totals.nblocks, + grand_totals.freespace, grand_totals.freechunks, + grand_totals.totalspace - grand_totals.freespace))); +} + +/* + * MemoryContextStatsInternal + * One recursion level for MemoryContextStats + * + * Print this context if print is true, but in any case accumulate counts into + * *totals (if given). + */ +static void +MemoryContextStatsInternal(MemoryContext context, int level, + bool print, int max_children, + MemoryContextCounters *totals, + bool print_to_stderr) +{ + MemoryContextCounters local_totals; + MemoryContext child; + int ichild; + + AssertArg(MemoryContextIsValid(context)); + + /* Examine the context itself */ + context->methods->stats(context, + print ? MemoryContextStatsPrint : NULL, + (void *) &level, + totals, print_to_stderr); + + /* + * Examine children. If there are more than max_children of them, we do + * not print the rest explicitly, but just summarize them. + */ + memset(&local_totals, 0, sizeof(local_totals)); + + for (child = context->firstchild, ichild = 0; + child != NULL; + child = child->nextchild, ichild++) + { + if (ichild < max_children) + MemoryContextStatsInternal(child, level + 1, + print, max_children, + totals, + print_to_stderr); + else + MemoryContextStatsInternal(child, level + 1, + false, max_children, + &local_totals, + print_to_stderr); + } + + /* Deal with excess children */ + if (ichild > max_children) + { + if (print) + { + if (print_to_stderr) + { + int i; + + for (i = 0; i <= level; i++) + fprintf(stderr, " "); + fprintf(stderr, + "%d more child contexts containing %zu total in %zd blocks; %zu free (%zd chunks); %zu used\n", + ichild - max_children, + local_totals.totalspace, + local_totals.nblocks, + local_totals.freespace, + local_totals.freechunks, + local_totals.totalspace - local_totals.freespace); + } + else + ereport(LOG_SERVER_ONLY, + (errhidestmt(true), + errhidecontext(true), + errmsg_internal("level: %d; %d more child contexts containing %zu total in %zd blocks; %zu free (%zd chunks); %zu used", + level, + ichild - max_children, + local_totals.totalspace, + local_totals.nblocks, + local_totals.freespace, + local_totals.freechunks, + local_totals.totalspace - local_totals.freespace))); + } + + if (totals) + { + totals->nblocks += local_totals.nblocks; + totals->freechunks += local_totals.freechunks; + totals->totalspace += local_totals.totalspace; + totals->freespace += local_totals.freespace; + } + } +} + +/* + * MemoryContextStatsPrint + * Print callback used by MemoryContextStatsInternal + * + * For now, the passthru pointer just points to "int level"; later we might + * make that more complicated. + */ +static void +MemoryContextStatsPrint(MemoryContext context, void *passthru, + const char *stats_string, + bool print_to_stderr) +{ + int level = *(int *) passthru; + const char *name = context->name; + const char *ident = context->ident; + char truncated_ident[110]; + int i; + + /* + * It seems preferable to label dynahash contexts with just the hash table + * name. Those are already unique enough, so the "dynahash" part isn't + * very helpful, and this way is more consistent with pre-v11 practice. + */ + if (ident && strcmp(name, "dynahash") == 0) + { + name = ident; + ident = NULL; + } + + truncated_ident[0] = '\0'; + + if (ident) + { + /* + * Some contexts may have very long identifiers (e.g., SQL queries). + * Arbitrarily truncate at 100 bytes, but be careful not to break + * multibyte characters. Also, replace ASCII control characters, such + * as newlines, with spaces. + */ + int idlen = strlen(ident); + bool truncated = false; + + strcpy(truncated_ident, ": "); + i = strlen(truncated_ident); + + if (idlen > 100) + { + idlen = pg_mbcliplen(ident, idlen, 100); + truncated = true; + } + + while (idlen-- > 0) + { + unsigned char c = *ident++; + + if (c < ' ') + c = ' '; + truncated_ident[i++] = c; + } + truncated_ident[i] = '\0'; + + if (truncated) + strcat(truncated_ident, "..."); + } + + if (print_to_stderr) + { + for (i = 0; i < level; i++) + fprintf(stderr, " "); + fprintf(stderr, "%s: %s%s\n", name, stats_string, truncated_ident); + } + else + ereport(LOG_SERVER_ONLY, + (errhidestmt(true), + errhidecontext(true), + errmsg_internal("level: %d; %s: %s%s", + level, name, stats_string, truncated_ident))); +} + +/* + * MemoryContextCheck + * Check all chunks in the named context. + * + * This is just a debugging utility, so it's not fancy. + */ +#ifdef MEMORY_CONTEXT_CHECKING +void +MemoryContextCheck(MemoryContext context) +{ + MemoryContext child; + + AssertArg(MemoryContextIsValid(context)); + + context->methods->check(context); + for (child = context->firstchild; child != NULL; child = child->nextchild) + MemoryContextCheck(child); +} +#endif + +/* + * MemoryContextContains + * Detect whether an allocated chunk of memory belongs to a given + * context or not. + * + * Caution: this test is reliable as long as 'pointer' does point to + * a chunk of memory allocated from *some* context. If 'pointer' points + * at memory obtained in some other way, there is a small chance of a + * false-positive result, since the bits right before it might look like + * a valid chunk header by chance. + */ +bool +MemoryContextContains(MemoryContext context, void *pointer) +{ + MemoryContext ptr_context; + + /* + * NB: Can't use GetMemoryChunkContext() here - that performs assertions + * that aren't acceptable here since we might be passed memory not + * allocated by any memory context. + * + * Try to detect bogus pointers handed to us, poorly though we can. + * Presumably, a pointer that isn't MAXALIGNED isn't pointing at an + * allocated chunk. + */ + if (pointer == NULL || pointer != (void *) MAXALIGN(pointer)) + return false; + + /* + * OK, it's probably safe to look at the context. + */ + ptr_context = *(MemoryContext *) (((char *) pointer) - sizeof(void *)); + + return ptr_context == context; +} + +/* + * MemoryContextCreate + * Context-type-independent part of context creation. + * + * This is only intended to be called by context-type-specific + * context creation routines, not by the unwashed masses. + * + * The memory context creation procedure goes like this: + * 1. Context-type-specific routine makes some initial space allocation, + * including enough space for the context header. If it fails, + * it can ereport() with no damage done. + * 2. Context-type-specific routine sets up all type-specific fields of + * the header (those beyond MemoryContextData proper), as well as any + * other management fields it needs to have a fully valid context. + * Usually, failure in this step is impossible, but if it's possible + * the initial space allocation should be freed before ereport'ing. + * 3. Context-type-specific routine calls MemoryContextCreate() to fill in + * the generic header fields and link the context into the context tree. + * 4. We return to the context-type-specific routine, which finishes + * up type-specific initialization. This routine can now do things + * that might fail (like allocate more memory), so long as it's + * sure the node is left in a state that delete will handle. + * + * node: the as-yet-uninitialized common part of the context header node. + * tag: NodeTag code identifying the memory context type. + * methods: context-type-specific methods (usually statically allocated). + * parent: parent context, or NULL if this will be a top-level context. + * name: name of context (must be statically allocated). + * + * Context routines generally assume that MemoryContextCreate can't fail, + * so this can contain Assert but not elog/ereport. + */ +void +MemoryContextCreate(MemoryContext node, + NodeTag tag, + const MemoryContextMethods *methods, + MemoryContext parent, + const char *name) +{ + /* Creating new memory contexts is not allowed in a critical section */ + Assert(CritSectionCount == 0); + + /* Initialize all standard fields of memory context header */ + node->type = tag; + node->isReset = true; + node->methods = methods; + node->parent = parent; + node->firstchild = NULL; + node->mem_allocated = 0; + node->prevchild = NULL; + node->name = name; + node->ident = NULL; + node->reset_cbs = NULL; + + /* OK to link node into context tree */ + if (parent) + { + node->nextchild = parent->firstchild; + if (parent->firstchild != NULL) + parent->firstchild->prevchild = node; + parent->firstchild = node; + /* inherit allowInCritSection flag from parent */ + node->allowInCritSection = parent->allowInCritSection; + } + else + { + node->nextchild = NULL; + node->allowInCritSection = false; + } + + VALGRIND_CREATE_MEMPOOL(node, 0, false); +} + +/* + * MemoryContextAlloc + * Allocate space within the specified context. + * + * This could be turned into a macro, but we'd have to import + * nodes/memnodes.h into postgres.h which seems a bad idea. + */ +void * +MemoryContextAlloc(MemoryContext context, Size size) +{ + void *ret; + + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); + + if (!AllocSizeIsValid(size)) + elog(ERROR, "invalid memory alloc request size %zu", size); + + context->isReset = false; + + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) + { + MemoryContextStats(TopMemoryContext); + + /* + * Here, and elsewhere in this module, we show the target context's + * "name" but not its "ident" (if any) in user-visible error messages. + * The "ident" string might contain security-sensitive data, such as + * values in SQL commands. + */ + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + + VALGRIND_MEMPOOL_ALLOC(context, ret, size); + + return ret; +} + +/* + * MemoryContextAllocZero + * Like MemoryContextAlloc, but clears allocated memory + * + * We could just call MemoryContextAlloc then clear the memory, but this + * is a very common combination, so we provide the combined operation. + */ +void * +MemoryContextAllocZero(MemoryContext context, Size size) +{ + void *ret; + + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); + + if (!AllocSizeIsValid(size)) + elog(ERROR, "invalid memory alloc request size %zu", size); + + context->isReset = false; + + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + + VALGRIND_MEMPOOL_ALLOC(context, ret, size); + + MemSetAligned(ret, 0, size); + + return ret; +} + +/* + * MemoryContextAllocZeroAligned + * MemoryContextAllocZero where length is suitable for MemSetLoop + * + * This might seem overly specialized, but it's not because newNode() + * is so often called with compile-time-constant sizes. + */ +void * +MemoryContextAllocZeroAligned(MemoryContext context, Size size) +{ + void *ret; + + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); + + if (!AllocSizeIsValid(size)) + elog(ERROR, "invalid memory alloc request size %zu", size); + + context->isReset = false; + + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + + VALGRIND_MEMPOOL_ALLOC(context, ret, size); + + MemSetLoop(ret, 0, size); + + return ret; +} + +/* + * MemoryContextAllocExtended + * Allocate space within the specified context using the given flags. + */ +void * +MemoryContextAllocExtended(MemoryContext context, Size size, int flags) +{ + void *ret; + + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); + + if (((flags & MCXT_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) || + ((flags & MCXT_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size))) + elog(ERROR, "invalid memory alloc request size %zu", size); + + context->isReset = false; + + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) + { + if ((flags & MCXT_ALLOC_NO_OOM) == 0) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + return NULL; + } + + VALGRIND_MEMPOOL_ALLOC(context, ret, size); + + if ((flags & MCXT_ALLOC_ZERO) != 0) + MemSetAligned(ret, 0, size); + + return ret; +} + +/* + * HandleLogMemoryContextInterrupt + * Handle receipt of an interrupt indicating logging of memory + * contexts. + * + * All the actual work is deferred to ProcessLogMemoryContextInterrupt(), + * because we cannot safely emit a log message inside the signal handler. + */ +void +HandleLogMemoryContextInterrupt(void) +{ + InterruptPending = true; + LogMemoryContextPending = true; + /* latch will be set by procsignal_sigusr1_handler */ +} + +/* + * ProcessLogMemoryContextInterrupt + * Perform logging of memory contexts of this backend process. + * + * Any backend that participates in ProcSignal signaling must arrange + * to call this function if we see LogMemoryContextPending set. + * It is called from CHECK_FOR_INTERRUPTS(), which is enough because + * the target process for logging of memory contexts is a backend. + */ +void +ProcessLogMemoryContextInterrupt(void) +{ + LogMemoryContextPending = false; + + /* + * Use LOG_SERVER_ONLY to prevent this message from being sent to the + * connected client. + */ + ereport(LOG_SERVER_ONLY, + (errhidestmt(true), + errhidecontext(true), + errmsg("logging memory contexts of PID %d", MyProcPid))); + + /* + * When a backend process is consuming huge memory, logging all its memory + * contexts might overrun available disk space. To prevent this, we limit + * the number of child contexts to log per parent to 100. + * + * As with MemoryContextStats(), we suppose that practical cases where the + * dump gets long will typically be huge numbers of siblings under the + * same parent context; while the additional debugging value from seeing + * details about individual siblings beyond 100 will not be large. + */ + MemoryContextStatsDetail(TopMemoryContext, 100, false); +} + +void * +palloc(Size size) +{ + /* duplicates MemoryContextAlloc to avoid increased overhead */ + void *ret; + MemoryContext context = CurrentMemoryContext; + + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); + + if (!AllocSizeIsValid(size)) + elog(ERROR, "invalid memory alloc request size %zu", size); + + context->isReset = false; + + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + + VALGRIND_MEMPOOL_ALLOC(context, ret, size); + + return ret; +} + +void * +palloc0(Size size) +{ + /* duplicates MemoryContextAllocZero to avoid increased overhead */ + void *ret; + MemoryContext context = CurrentMemoryContext; + + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); + + if (!AllocSizeIsValid(size)) + elog(ERROR, "invalid memory alloc request size %zu", size); + + context->isReset = false; + + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + + VALGRIND_MEMPOOL_ALLOC(context, ret, size); + + MemSetAligned(ret, 0, size); + + return ret; +} + +void * +palloc_extended(Size size, int flags) +{ + /* duplicates MemoryContextAllocExtended to avoid increased overhead */ + void *ret; + MemoryContext context = CurrentMemoryContext; + + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); + + if (((flags & MCXT_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) || + ((flags & MCXT_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size))) + elog(ERROR, "invalid memory alloc request size %zu", size); + + context->isReset = false; + + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) + { + if ((flags & MCXT_ALLOC_NO_OOM) == 0) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + return NULL; + } + + VALGRIND_MEMPOOL_ALLOC(context, ret, size); + + if ((flags & MCXT_ALLOC_ZERO) != 0) + MemSetAligned(ret, 0, size); + + return ret; +} + +/* + * pfree + * Release an allocated chunk. + */ +void +pfree(void *pointer) +{ + MemoryContext context = GetMemoryChunkContext(pointer); + + context->methods->free_p(context, pointer); + VALGRIND_MEMPOOL_FREE(context, pointer); +} + +/* + * repalloc + * Adjust the size of a previously allocated chunk. + */ +void * +repalloc(void *pointer, Size size) +{ + MemoryContext context = GetMemoryChunkContext(pointer); + void *ret; + + if (!AllocSizeIsValid(size)) + elog(ERROR, "invalid memory alloc request size %zu", size); + + AssertNotInCriticalSection(context); + + /* isReset must be false already */ + Assert(!context->isReset); + + ret = context->methods->realloc(context, pointer, size); + if (unlikely(ret == NULL)) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + + VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size); + + return ret; +} + +/* + * MemoryContextAllocHuge + * Allocate (possibly-expansive) space within the specified context. + * + * See considerations in comment at MaxAllocHugeSize. + */ +void * +MemoryContextAllocHuge(MemoryContext context, Size size) +{ + void *ret; + + AssertArg(MemoryContextIsValid(context)); + AssertNotInCriticalSection(context); + + if (!AllocHugeSizeIsValid(size)) + elog(ERROR, "invalid memory alloc request size %zu", size); + + context->isReset = false; + + ret = context->methods->alloc(context, size); + if (unlikely(ret == NULL)) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + + VALGRIND_MEMPOOL_ALLOC(context, ret, size); + + return ret; +} + +/* + * repalloc_huge + * Adjust the size of a previously allocated chunk, permitting a large + * value. The previous allocation need not have been "huge". + */ +void * +repalloc_huge(void *pointer, Size size) +{ + MemoryContext context = GetMemoryChunkContext(pointer); + void *ret; + + if (!AllocHugeSizeIsValid(size)) + elog(ERROR, "invalid memory alloc request size %zu", size); + + AssertNotInCriticalSection(context); + + /* isReset must be false already */ + Assert(!context->isReset); + + ret = context->methods->realloc(context, pointer, size); + if (unlikely(ret == NULL)) + { + MemoryContextStats(TopMemoryContext); + ereport(ERROR, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"), + errdetail("Failed on request of size %zu in memory context \"%s\".", + size, context->name))); + } + + VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size); + + return ret; +} + +/* + * MemoryContextStrdup + * Like strdup(), but allocate from the specified context + */ +char * +MemoryContextStrdup(MemoryContext context, const char *string) +{ + char *nstr; + Size len = strlen(string) + 1; + + nstr = (char *) MemoryContextAlloc(context, len); + + memcpy(nstr, string, len); + + return nstr; +} + +char * +pstrdup(const char *in) +{ + return MemoryContextStrdup(CurrentMemoryContext, in); +} + +/* + * pnstrdup + * Like pstrdup(), but append null byte to a + * not-necessarily-null-terminated input string. + */ +char * +pnstrdup(const char *in, Size len) +{ + char *out; + + len = strnlen(in, len); + + out = palloc(len + 1); + memcpy(out, in, len); + out[len] = '\0'; + + return out; +} + +/* + * Make copy of string with all trailing newline characters removed. + */ +char * +pchomp(const char *in) +{ + size_t n; + + n = strlen(in); + while (n > 0 && in[n - 1] == '\n') + n--; + return pnstrdup(in, n); +} |