Commit 8582cb96 authored by Aaron Tomlin's avatar Aaron Tomlin Committed by Linus Torvalds

mm: document improved handling of swappiness==0

Prior to 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.

[akpm@linux-foundation.org: remove comma, per Randy]
Signed-off-by: default avatarAaron Tomlin <atomlin@redhat.com>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Acked-by: default avatarBryn M. Reeves <bmr@redhat.com>
Cc: Satoru Moriya <satoru.moriya@hds.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0368dfd0
...@@ -696,7 +696,9 @@ swappiness ...@@ -696,7 +696,9 @@ swappiness
This control is used to define how aggressive the kernel will swap This control is used to define how aggressive the kernel will swap
memory pages. Higher values will increase agressiveness, lower values 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. The default value is 60.
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment