Messages in this thread Patch in this message | | | From | Aaron Tomlin <> | Subject | [PATCH] mm: Document improved handling of swappiness==0 | Date | Fri, 24 Jan 2014 15:13:28 +0000 |
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Prior to upstream commit fe35004f ("[mm] avoid swapping out with swappiness==0") setting swappiness to 0, reclaim code could still evict recently used user anonymous memory to swap even though there is a significant amount of RAM used for page cache.
The behaviour of setting swappiness to 0 has since changed. When set, the reclaim code does not initiate swap until the amount of free pages and file-backed pages, is less than the high water mark in a zone.
Let's update the documentation to reflect this.
Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Bryn M. Reeves <bmr@redhat.com> --- Documentation/sysctl/vm.txt | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 9f5481b..38388ee 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -696,7 +696,9 @@ swappiness This control is used to define how aggressive the kernel will swap memory pages. Higher values will increase agressiveness, lower values -decrease the amount of swap. +decrease the amount of swap. A value of 0 instructs the kernel not to +initiate swap until the amount of free and file-backed pages, is less +than the high water mark in a zone. The default value is 60. -- 1.8.4.2
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