path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 17:50:35 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 17:50:35 -0800
commit5ce1a70e2f00f0bce0cab57f798ca354b9496169 (patch)
tree6e80200536b7a3576fd71ff2c7135ffe87dc858e /Documentation
parentMerge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc (diff)
parentksm: allocate roots when needed (diff)
Merge branch 'akpm' (more incoming from Andrew)
Merge second patch-bomb from Andrew Morton: - A little DM fix - the MM queue * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (154 commits) ksm: allocate roots when needed mm: cleanup "swapcache" in do_swap_page mm,ksm: swapoff might need to copy mm,ksm: FOLL_MIGRATION do migration_entry_wait ksm: shrink 32-bit rmap_item back to 32 bytes ksm: treat unstable nid like in stable tree ksm: add some comments tmpfs: fix mempolicy object leaks tmpfs: fix use-after-free of mempolicy object mm/fadvise.c: drain all pagevecs if POSIX_FADV_DONTNEED fails to discard all pages mm: export mmu notifier invalidates mm: accelerate mm_populate() treatment of THP pages mm: use long type for page counts in mm_populate() and get_user_pages() mm: accurately document nr_free_*_pages functions with code comments HWPOISON: change order of error_states[]'s elements HWPOISON: fix misjudgement of page_action() for errors on mlocked pages memcg: stop warning on memcg_propagate_kmem net: change type of virtio_chan->p9_max_pages vmscan: change type of vm_total_pages to unsigned long fs/nfsd: change type of max_delegations, nfsd_drc_max_mem and nfsd_drc_mem_used ...
Diffstat (limited to 'Documentation')
3 files changed, 103 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-ksm b/Documentation/ABI/testing/sysfs-kernel-mm-ksm
new file mode 100644
index 000000000000..73e653ee2481
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-ksm
@@ -0,0 +1,52 @@
+What: /sys/kernel/mm/ksm
+Date: September 2009
+KernelVersion: 2.6.32
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Interface for Kernel Samepage Merging (KSM)
+What: /sys/kernel/mm/ksm/full_scans
+What: /sys/kernel/mm/ksm/pages_shared
+What: /sys/kernel/mm/ksm/pages_sharing
+What: /sys/kernel/mm/ksm/pages_to_scan
+What: /sys/kernel/mm/ksm/pages_unshared
+What: /sys/kernel/mm/ksm/pages_volatile
+What: /sys/kernel/mm/ksm/run
+What: /sys/kernel/mm/ksm/sleep_millisecs
+Date: September 2009
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Kernel Samepage Merging daemon sysfs interface
+ full_scans: how many times all mergeable areas have been
+ scanned.
+ pages_shared: how many shared pages are being used.
+ pages_sharing: how many more sites are sharing them i.e. how
+ much saved.
+ pages_to_scan: how many present pages to scan before ksmd goes
+ to sleep.
+ pages_unshared: how many pages unique but repeatedly checked
+ for merging.
+ pages_volatile: how many pages changing too fast to be placed
+ in a tree.
+ run: write 0 to disable ksm, read 0 while ksm is disabled.
+ write 1 to run ksm, read 1 while ksm is running.
+ write 2 to disable ksm and unmerge all its pages.
+ sleep_millisecs: how many milliseconds ksm should sleep between
+ scans.
+ See Documentation/vm/ksm.txt for more information.
+What: /sys/kernel/mm/ksm/merge_across_nodes
+Date: January 2013
+KernelVersion: 3.9
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Control merging pages across different NUMA nodes.
+ When it is set to 0 only pages from the same node are merged,
+ otherwise pages from all nodes can be merged together (default).
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 9aa8ff3e54dc..766087781ecd 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1640,6 +1640,42 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
that the amount of memory usable for all allocations
is not too small.
+ movablemem_map=acpi
+ [KNL,X86,IA-64,PPC] This parameter is similar to
+ memmap except it specifies the memory map of
+ This option inform the kernel to use Hot Pluggable bit
+ in flags from SRAT from ACPI BIOS to determine which
+ memory devices could be hotplugged. The corresponding
+ memory ranges will be set as ZONE_MOVABLE.
+ NOTE: Whatever node the kernel resides in will always
+ be un-hotpluggable.
+ movablemem_map=nn[KMG]@ss[KMG]
+ [KNL,X86,IA-64,PPC] This parameter is similar to
+ memmap except it specifies the memory map of
+ If user specifies memory ranges, the info in SRAT will
+ be ingored. And it works like the following:
+ - If more ranges are all within one node, then from
+ lowest ss to the end of the node will be ZONE_MOVABLE.
+ - If a range is within a node, then from ss to the end
+ of the node will be ZONE_MOVABLE.
+ - If a range covers two or more nodes, then from ss to
+ the end of the 1st node will be ZONE_MOVABLE, and all
+ the rest nodes will only have ZONE_MOVABLE.
+ If memmap is specified at the same time, the
+ movablemem_map will be limited within the memmap
+ areas. If kernelcore or movablecore is also specified,
+ movablemem_map will have higher priority to be
+ satisfied. So the administrator should be careful that
+ the amount of movablemem_map areas are not too large.
+ Otherwise kernel won't have enough memory to start.
+ NOTE: We don't stop users specifying the node the
+ kernel resides in as hotpluggable so that this
+ option can be used as a workaround of firmware
+ bugs.
MTD_Partition= [MTD]
Format: <name>,<region-number>,<size>,<offset>
diff --git a/Documentation/vm/ksm.txt b/Documentation/vm/ksm.txt
index b392e496f816..f34a8ee6f860 100644
--- a/Documentation/vm/ksm.txt
+++ b/Documentation/vm/ksm.txt
@@ -58,6 +58,21 @@ sleep_millisecs - how many milliseconds ksmd should sleep before next scan
e.g. "echo 20 > /sys/kernel/mm/ksm/sleep_millisecs"
Default: 20 (chosen for demonstration purposes)
+merge_across_nodes - specifies if pages from different numa nodes can be merged.
+ When set to 0, ksm merges only pages which physically
+ reside in the memory area of same NUMA node. That brings
+ lower latency to access of shared pages. Systems with more
+ nodes, at significant NUMA distances, are likely to benefit
+ from the lower latency of setting 0. Smaller systems, which
+ need to minimize memory usage, are likely to benefit from
+ the greater sharing of setting 1 (default). You may wish to
+ compare how your system performs under each setting, before
+ deciding on which to use. merge_across_nodes setting can be
+ changed only when there are no ksm shared pages in system:
+ set run 2 to unmerge pages first, then to 1 after changing
+ merge_across_nodes, to remerge according to the new setting.
+ Default: 1 (merging across nodes as in earlier releases)
run - set 0 to stop ksmd from running but keep merged pages,
set 1 to run ksmd e.g. "echo 1 > /sys/kernel/mm/ksm/run",
set 2 to stop ksmd and unmerge all pages currently merged,