linux-kernel - [PATCH v4 12/16] memcg: enable accounting for posix_timers

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Message-ID: <41e1ebc8-4f95-4a3f-3665-3fe139786d8e@virtuozzo.com>
Date:   Wed, 28 Apr 2021 09:53:50 +0300
From:   Vasily Averin <vvs@...tuozzo.com>
To:     cgroups@...r.kernel.org, Michal Hocko <mhocko@...nel.org>,
        Shakeel Butt <shakeelb@...gle.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Vladimir Davydov <vdavydov.dev@...il.com>
Cc:     Roman Gushchin <guro@...com>, Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 12/16] memcg: enable accounting for posix_timers_cache slab

A program may create multiple interval timers using timer_create().
For each timer the kernel preallocates a "queued real-time signal",
Consequently, the number of timers is limited by the RLIMIT_SIGPENDING
resource limit. The allocated object is quite small, ~250 bytes,
but even the default signal limits allow to consume up to 100 megabytes
per user.

It makes sense to account for them to limit the host's memory consumption
from inside the memcg-limited container.

Signed-off-by: Vasily Averin <vvs@...tuozzo.com>
---
 kernel/time/posix-timers.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index bf540f5a..2eee615 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -273,8 +273,8 @@ static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec64 *tp)
 static __init int init_posix_timers(void)
 {
 	posix_timers_cache = kmem_cache_create("posix_timers_cache",
-					sizeof (struct k_itimer), 0, SLAB_PANIC,
-					NULL);
+					sizeof(struct k_itimer), 0,
+					SLAB_PANIC | SLAB_ACCOUNT, NULL);
 	return 0;
 }
 __initcall(init_posix_timers);
-- 
1.8.3.1