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-rw-r--r--Documentation/vm/ksm.txt13
1 files changed, 7 insertions, 6 deletions
diff --git a/Documentation/vm/ksm.txt b/Documentation/vm/ksm.txt
index 72a22f65960e..262d8e6793a3 100644
--- a/Documentation/vm/ksm.txt
+++ b/Documentation/vm/ksm.txt
@@ -52,15 +52,15 @@ The KSM daemon is controlled by sysfs files in /sys/kernel/mm/ksm/,
readable by all but writable only by root:
max_kernel_pages - set to maximum number of kernel pages that KSM may use
- e.g. "echo 2000 > /sys/kernel/mm/ksm/max_kernel_pages"
+ e.g. "echo 100000 > /sys/kernel/mm/ksm/max_kernel_pages"
Value 0 imposes no limit on the kernel pages KSM may use;
but note that any process using MADV_MERGEABLE can cause
KSM to allocate these pages, unswappable until it exits.
- Default: 2000 (chosen for demonstration purposes)
+ Default: quarter of memory (chosen to not pin too much)
pages_to_scan - how many present pages to scan before ksmd goes to sleep
- e.g. "echo 200 > /sys/kernel/mm/ksm/pages_to_scan"
- Default: 200 (chosen for demonstration purposes)
+ e.g. "echo 100 > /sys/kernel/mm/ksm/pages_to_scan"
+ Default: 100 (chosen for demonstration purposes)
sleep_millisecs - how many milliseconds ksmd should sleep before next scan
e.g. "echo 20 > /sys/kernel/mm/ksm/sleep_millisecs"
@@ -70,7 +70,8 @@ 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,
but leave mergeable areas registered for next run
- Default: 1 (for immediate use by apps which register)
+ Default: 0 (must be changed to 1 to activate KSM,
+ except if CONFIG_SYSFS is disabled)
The effectiveness of KSM and MADV_MERGEABLE is shown in /sys/kernel/mm/ksm/:
@@ -86,4 +87,4 @@ pages_volatile embraces several different kinds of activity, but a high
proportion there would also indicate poor use of madvise MADV_MERGEABLE.
Izik Eidus,
-Hugh Dickins, 30 July 2009
+Hugh Dickins, 24 Sept 2009