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
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Vasily Averin <vvs@xxxxxxxxxxxxx>
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@xxxxxxxxxx/
Link: https://lkml.kernel.org/r/90e254df-0dfe-f080-011e-b7c53ee7fd20@xxxxxxxxxxxxx
Fixes: 18319498fdd4 ("memcg: enable accounting of ipc resources")
Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxx are
ipc-remove-memcg-accounting-for-sops-objects-in-do_semtimedop.patch
