ksm: add sysfs ABI Documentation
Add sysfs documentation for Kernel Samepage Merging (KSM) including new
merge_across_nodes knob.
Signed-off-by: Petr Holasek <pholasek@redhat.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Izik Eidus <izik.eidus@ravellosystems.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-ksm b/Documentation/ABI/testing/sysfs-kernel-mm-ksm
new file mode 100644
index 0000000..73e653e
--- /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).