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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 02:42:50 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 02:42:50 +0000
commit8cb83eee5a58b1fad74c34094ce3afb9e430b5a4 (patch)
treea9b2e7baeca1be40eb734371e3c8b11b02294497 /sys-utils/chmem.8
parentInitial commit. (diff)
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util-linux-upstream.zip
Adding upstream version 2.33.1.upstream/2.33.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+.TH CHMEM 8 "October 2016" "util-linux" "System Administration"
+.SH NAME
+chmem \- configure memory
+.SH SYNOPSIS
+.B chmem
+.RB [ \-h "] [" \-V "] [" \-v "] [" \-e | \-d "]"
+[\fISIZE\fP|\fIRANGE\fP|\fB\-b\fP \fIBLOCKRANGE\fP]
+[-z ZONE]
+.SH DESCRIPTION
+The chmem command sets a particular size or range of memory online or offline.
+.
+.IP "\(hy" 2
+Specify \fISIZE\fP as <size>[m|M|g|G]. With m or M, <size> specifies the memory
+size in MiB (1024 x 1024 bytes). With g or G, <size> specifies the memory size
+in GiB (1024 x 1024 x 1024 bytes). The default unit is MiB.
+.
+.IP "\(hy" 2
+Specify \fIRANGE\fP in the form 0x<start>-0x<end> as shown in the output of the
+\fBlsmem\fP command. <start> is the hexadecimal address of the first byte and <end>
+is the hexadecimal address of the last byte in the memory range.
+.
+.IP "\(hy" 2
+Specify \fIBLOCKRANGE\fP in the form <first>-<last> or <block> as shown in the
+output of the \fBlsmem\fP command. <first> is the number of the first memory block
+and <last> is the number of the last memory block in the memory
+range. Alternatively a single block can be specified. \fIBLOCKRANGE\fP requires
+the \fB--blocks\fP option.
+.
+.IP "\(hy" 2
+Specify \fIZONE\fP as the name of a memory zone, as shown in the output of the
+\fBlsmem -o +ZONES\fP command. The output shows one or more valid memory zones
+for each memory range. If multiple zones are shown, then the memory range
+currently belongs to the first zone. By default, chmem will set memory online
+to the zone Movable, if this is among the valid zones. This default can be
+changed by specifying the \fB--zone\fP option with another valid zone.
+For memory ballooning, it is recommended to select the zone Movable for memory
+online and offline, if possible. Memory in this zone is much more likely to be
+able to be offlined again, but it cannot be used for arbitrary kernel
+allocations, only for migratable pages (e.g. anonymous and page cache pages).
+Use the \fB\-\-help\fR option to see all available zones.
+.
+.PP
+\fISIZE\fP and \fIRANGE\fP must be aligned to the Linux memory block size, as
+shown in the output of the \fBlsmem\fP command.
+
+Setting memory online can fail for various reasons. On virtualized systems it
+can fail if the hypervisor does not have enough memory left, for example
+because memory was overcommitted. Setting memory offline can fail if Linux
+cannot free the memory. If only part of the requested memory can be set online
+or offline, a message tells you how much memory was set online or offline
+instead of the requested amount.
+
+When setting memory online \fBchmem\fP starts with the lowest memory block
+numbers. When setting memory offline \fBchmem\fP starts with the highest memory
+block numbers.
+.SH OPTIONS
+.TP
+.BR \-b ", " \-\-blocks
+Use a \fIBLOCKRANGE\fP parameter instead of \fIRANGE\fP or \fISIZE\fP for the
+\fB--enable\fP and \fB--disable\fP options.
+.TP
+.BR \-d ", " \-\-disable
+Set the specified \fIRANGE\fP, \fISIZE\fP, or \fIBLOCKRANGE\fP of memory offline.
+.TP
+.BR \-e ", " \-\-enable
+Set the specified \fIRANGE\fP, \fISIZE\fP, or \fIBLOCKRANGE\fP of memory online.
+.TP
+.BR \-z ", " \-\-zone
+Select the memory \fIZONE\fP where to set the specified \fIRANGE\fP, \fISIZE\fP,
+or \fIBLOCKRANGE\fP of memory online or offline. By default, memory will be set
+online to the zone Movable, if possible.
+.TP
+.BR \-h ", " \-\-help
+Print a short help text, then exit.
+.TP
+.BR \-v ", " \-\-verbose
+Verbose mode. Causes \fBchmem\fP to print debugging messages about it's
+progress.
+.TP
+.BR \-V ", " \-\-version
+Print the version number, then exit.
+.SH RETURN CODES
+.B chmem
+has the following return codes:
+.TP
+.B 0
+success
+.TP
+.B 1
+failure
+.TP
+.B 64
+partial success
+.SH EXAMPLES
+.TP
+.B chmem --enable 1024
+This command requests 1024 MiB of memory to be set online.
+.TP
+.B chmem -e 2g
+This command requests 2 GiB of memory to be set online.
+.TP
+.B chmem --disable 0x00000000e4000000-0x00000000f3ffffff
+This command requests the memory range starting with 0x00000000e4000000
+and ending with 0x00000000f3ffffff to be set offline.
+.TP
+.B chmem -b -d 10
+This command requests the memory block number 10 to be set offline.
+.SH SEE ALSO
+.BR lsmem (1)
+.SH AVAILABILITY
+The \fBchmem\fP command is part of the util-linux package and is available from
+.UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
+Linux Kernel Archive
+.UE .