+ ipc-remove-memcg-accounting-for-sops-objects-in-do_semtimedop.patch added to -mm tree

+ ipc-remove-memcg-accounting-for-sops-objects-in-do_semtimedop.patch added to -mm tree

[akpm]

The patch titled
     Subject: ipc: remove memcg accounting for sops objects in do_semtimedop()
has been added to the -mm tree.  Its filename is
     ipc-remove-memcg-accounting-for-sops-objects-in-do_semtimedop.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/ipc-remove-memcg-accounting-for-sops-objects-in-do_semtimedop.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/ipc-remove-memcg-accounting-for-sops-objects-in-do_semtimedop.patch

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------------------------------------------------------
From: Vasily Averin <vvs@virtuozzo.com>
Subject: ipc: remove memcg accounting for sops objects in do_semtimedop()

Linus proposes to revert an accounting for sops objects in do_semtimedop()
because it's really just a temporary buffer for a single semtimedop()
system call.

This object can consume up to 2 pages, syscall is sleeping one, size and
duration can be controlled by user, and this allocation can be repeated by
many thread at the same time.

However Shakeel Butt pointed that there are much more popular objects with
the same life time and similar memory consumption, the accounting of which
was decided to be rejected for performance reasons.

In addition, any usual task consumes much more accounted memory, so 2
pages of this temporal buffer can be safely ignored.

Link: https://patchwork.kernel.org/project/linux-fsdevel/patch/20171005222144.123797-1-shakeelb@google.com/
Link: https://lkml.kernel.org/r/90e254df-0dfe-f080-011e-b7c53ee7fd20@virtuozzo.com
Fixes: 18319498fdd4 ("memcg: enable accounting of ipc resources")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 ipc/sem.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/ipc/sem.c~ipc-remove-memcg-accounting-for-sops-objects-in-do_semtimedop
+++ a/ipc/sem.c
@@ -2005,8 +2005,7 @@ static long do_semtimedop(int semid, str
 	if (nsops > ns->sc_semopm)
 		return -E2BIG;
 	if (nsops > SEMOPM_FAST) {
-		sops = kvmalloc_array(nsops, sizeof(*sops),
-				      GFP_KERNEL_ACCOUNT);
+		sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
 		if (sops == NULL)
 			return -ENOMEM;
 	}
_

Patches currently in -mm which might be from vvs@virtuozzo.com are

ipc-remove-memcg-accounting-for-sops-objects-in-do_semtimedop.patch