From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Shakeel Butt <shakeelb@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: [PATCH v4] mm/memcg: try harder to decrease [memory,memsw].limit_in_bytes
Date: Wed, 10 Jan 2018 15:43:17 +0300 [thread overview]
Message-ID: <20180110124317.28887-1-aryabinin@virtuozzo.com> (raw)
In-Reply-To: <20180109152622.31ca558acb0cc25a1b14f38c@linux-foundation.org>
mem_cgroup_resize_[memsw]_limit() tries to free only 32 (SWAP_CLUSTER_MAX)
pages on each iteration. This makes practically impossible to decrease
limit of memory cgroup. Tasks could easily allocate back 32 pages,
so we can't reduce memory usage, and once retry_count reaches zero we return
-EBUSY.
Easy to reproduce the problem by running the following commands:
mkdir /sys/fs/cgroup/memory/test
echo $$ >> /sys/fs/cgroup/memory/test/tasks
cat big_file > /dev/null &
sleep 1 && echo $((100*1024*1024)) > /sys/fs/cgroup/memory/test/memory.limit_in_bytes
-bash: echo: write error: Device or resource busy
Instead of relying on retry_count, keep retrying the reclaim until
the desired limit is reached or fail if the reclaim doesn't make
any progress or a signal is pending.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
Changes since v3:
- Rebase
Changes since v2:
- Changelog wording per mhocko@
mm/memcontrol.c | 44 ++++++++------------------------------------
1 file changed, 8 insertions(+), 36 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 13aeccf32c2e..c3d1eaef752d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1176,20 +1176,6 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
}
/*
- * This function returns the number of memcg under hierarchy tree. Returns
- * 1(self count) if no children.
- */
-static int mem_cgroup_count_children(struct mem_cgroup *memcg)
-{
- int num = 0;
- struct mem_cgroup *iter;
-
- for_each_mem_cgroup_tree(iter, memcg)
- num++;
- return num;
-}
-
-/*
* Return the memory (and swap, if configured) limit for a memcg.
*/
unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
@@ -2462,24 +2448,12 @@ static DEFINE_MUTEX(memcg_limit_mutex);
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
unsigned long limit, bool memsw)
{
- unsigned long curusage;
- unsigned long oldusage;
+ unsigned long usage;
bool enlarge = false;
- int retry_count;
int ret;
bool limits_invariant;
struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
- /*
- * For keeping hierarchical_reclaim simple, how long we should retry
- * is depends on callers. We set our retry-count to be function
- * of # of children which we should visit in this loop.
- */
- retry_count = MEM_CGROUP_RECLAIM_RETRIES *
- mem_cgroup_count_children(memcg);
-
- oldusage = page_counter_read(counter);
-
do {
if (signal_pending(current)) {
ret = -EINTR;
@@ -2506,15 +2480,13 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
if (!ret)
break;
- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);
-
- curusage = page_counter_read(counter);
- /* Usage is reduced ? */
- if (curusage >= oldusage)
- retry_count--;
- else
- oldusage = curusage;
- } while (retry_count);
+ usage = page_counter_read(counter);
+ if (!try_to_free_mem_cgroup_pages(memcg, usage - limit,
+ GFP_KERNEL, !memsw)) {
+ ret = -EBUSY;
+ break;
+ }
+ } while (true);
if (!ret && enlarge)
memcg_oom_recover(memcg);
--
2.13.6
next prev parent reply other threads:[~2018-01-10 12:43 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-20 10:24 [PATCH 1/2] mm/memcg: try harder to decrease [memory,memsw].limit_in_bytes Andrey Ryabinin
2017-12-20 10:24 ` [PATCH 2/2] mm/memcg: Consolidate mem_cgroup_resize_[memsw]_limit() functions Andrey Ryabinin
2017-12-20 10:33 ` [PATCH 1/2] mm/memcg: try harder to decrease [memory,memsw].limit_in_bytes Michal Hocko
2017-12-20 11:32 ` Andrey Ryabinin
2017-12-20 11:34 ` Michal Hocko
2017-12-20 18:15 ` Shakeel Butt
2017-12-21 10:00 ` Andrey Ryabinin
2017-12-20 13:21 ` [PATCH v2 " Andrey Ryabinin
2017-12-20 13:21 ` [PATCH v2 2/2] mm/memcg: Consolidate mem_cgroup_resize_[memsw]_limit() functions Andrey Ryabinin
2017-12-20 13:53 ` [PATCH v2 1/2] mm/memcg: try harder to decrease [memory,memsw].limit_in_bytes Michal Hocko
2018-01-09 16:58 ` [PATCH v3 " Andrey Ryabinin
2018-01-09 16:58 ` [PATCH v3 2/2] mm/memcg: Consolidate mem_cgroup_resize_[memsw]_limit() functions Andrey Ryabinin
2018-01-09 17:10 ` Shakeel Butt
2018-01-09 17:26 ` Andrey Ryabinin
2018-01-09 23:26 ` Andrew Morton
2018-01-10 12:43 ` Andrey Ryabinin [this message]
2018-01-10 22:31 ` [PATCH v4] mm/memcg: try harder to decrease [memory,memsw].limit_in_bytes Andrew Morton
2018-01-11 11:59 ` Andrey Ryabinin
2018-01-12 0:21 ` Andrew Morton
2018-01-12 9:08 ` Andrey Ryabinin
2018-01-11 10:42 ` Michal Hocko
2018-01-11 12:21 ` Andrey Ryabinin
2018-01-11 12:46 ` Michal Hocko
2018-01-11 15:23 ` Andrey Ryabinin
2018-01-11 16:29 ` Michal Hocko
2018-01-11 21:59 ` Andrey Ryabinin
2018-01-12 12:24 ` Michal Hocko
2018-01-12 22:57 ` Shakeel Butt
2018-01-15 12:29 ` Andrey Ryabinin
2018-01-15 17:04 ` Shakeel Butt
2018-01-15 12:30 ` Andrey Ryabinin
2018-01-15 12:46 ` Michal Hocko
2018-01-15 12:53 ` Andrey Ryabinin
2018-01-15 12:58 ` Michal Hocko
2018-01-09 17:08 ` [PATCH v3 1/2] " Andrey Ryabinin
2018-01-09 17:22 ` Shakeel Butt
2018-01-19 13:25 ` [PATCH v5 1/2] mm/memcontrol.c: " Andrey Ryabinin
2018-01-19 13:25 ` [PATCH v5 2/2] mm/memcontrol.c: Reduce reclaim retries in mem_cgroup_resize_limit() Andrey Ryabinin
2018-01-19 13:35 ` Michal Hocko
2018-01-19 14:49 ` Shakeel Butt
2018-01-19 15:11 ` Michal Hocko
2018-01-19 15:24 ` Shakeel Butt
2018-01-19 15:31 ` Michal Hocko
2018-02-21 20:17 ` Andrew Morton
2018-02-22 13:50 ` Andrey Ryabinin
2018-02-22 14:09 ` Michal Hocko
2018-02-22 15:13 ` Andrey Ryabinin
2018-02-22 15:33 ` Michal Hocko
2018-02-22 15:38 ` Andrey Ryabinin
2018-02-22 15:44 ` Michal Hocko
2018-02-22 16:01 ` Andrey Ryabinin
2018-02-22 16:30 ` Michal Hocko
2018-01-19 13:32 ` [PATCH v5 1/2] mm/memcontrol.c: try harder to decrease [memory,memsw].limit_in_bytes Michal Hocko
2018-01-25 19:44 ` Andrey Ryabinin
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