Commit d5fffc5a authored by zhangkui's avatar zhangkui Committed by Linus Torvalds
Browse files

mm/madvise: add MADV_WILLNEED to process_madvise()

There is a usecase in Android that an app process's memory is swapped out
by process_madvise() with MADV_PAGEOUT, such as the memory is swapped to
zram or a backing device.  When the process is scheduled to running, like
switch to foreground, multiple page faults may cause the app dropped
frames.

To reduce the problem, System Management Software can read-ahead memory
of the process immediately when the app switches to forground.  Calling
process_madvise() with MADV_WILLNEED can meet this need.

Link: https://lkml.kernel.org/r/20210804082010.12482-1-zhangkui@oppo.com

Signed-off-by: default avatarzhangkui <zhangkui@oppo.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 33090af9
......@@ -1048,6 +1048,7 @@ process_madvise_behavior_valid(int behavior)
switch (behavior) {
case MADV_COLD:
case MADV_PAGEOUT:
case MADV_WILLNEED:
return true;
default:
return false;
......
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