From: Michal Hocko <mhocko@kernel.org>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrew Morton <akpm@linux-foundation.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>
Subject: Re: [PATCH v4] mm/memcg: try harder to decrease [memory,memsw].limit_in_bytes
Date: Thu, 11 Jan 2018 13:46:29 +0100 [thread overview]
Message-ID: <20180111124629.GA1732@dhcp22.suse.cz> (raw)
In-Reply-To: <4a8f667d-c2ae-e3df-00fd-edc01afe19e1@virtuozzo.com>
On Thu 11-01-18 15:21:33, Andrey Ryabinin wrote:
>
>
> On 01/11/2018 01:42 PM, Michal Hocko wrote:
> > On Wed 10-01-18 15:43:17, Andrey Ryabinin wrote:
> > [...]
> >> @@ -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)) {
> >
> > If the usage drops below limit in the meantime then you get underflow
> > and reclaim the whole memcg. I do not think this is a good idea. This
> > can also lead to over reclaim. Why don't you simply stick with the
> > original SWAP_CLUSTER_MAX (aka 1 for try_to_free_mem_cgroup_pages)?
> >
>
> Because, if new limit is gigabytes bellow the current usage, retrying to set
> new limit after reclaiming only 32 pages seems unreasonable.
Who would do insanity like that?
> @@ -2487,8 +2487,8 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> if (!ret)
> break;
>
> - usage = page_counter_read(counter);
> - if (!try_to_free_mem_cgroup_pages(memcg, usage - limit,
> + nr_pages = max_t(long, 1, page_counter_read(counter) - limit);
> + if (!try_to_free_mem_cgroup_pages(memcg, nr_pages,
> GFP_KERNEL, !memsw)) {
> ret = -EBUSY;
> break;
How does this address the over reclaim concern?
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2018-01-11 12:46 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 ` [PATCH v4] mm/memcg: try harder to decrease [memory,memsw].limit_in_bytes Andrey Ryabinin
2018-01-10 22:31 ` 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 [this message]
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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