+ mm-madvise-add-madv_willneed-to-process_madvise.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: mm/madvise: add MADV_WILLNEED to process_madvise()
has been added to the -mm tree.  Its filename is
     mm-madvise-add-madv_willneed-to-process_madvise.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-madvise-add-madv_willneed-to-process_madvise.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-madvise-add-madv_willneed-to-process_madvise.patch

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------------------------------------------------------
From: zhangkui <zhangkui@oppo.com>
Subject: 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, SMS 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: zhangkui <zhangkui@oppo.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/madvise.c |    1 +
 1 file changed, 1 insertion(+)

--- a/mm/madvise.c~mm-madvise-add-madv_willneed-to-process_madvise
+++ a/mm/madvise.c
@@ -1048,6 +1048,7 @@ process_madvise_behavior_valid(int behav
 	switch (behavior) {
 	case MADV_COLD:
 	case MADV_PAGEOUT:
+	case MADV_WILLNEED:
 		return true;
 	default:
 		return false;
_

Patches currently in -mm which might be from zhangkui@oppo.com are

mm-madvise-add-madv_willneed-to-process_madvise.patch