From: Michal Hocko <mhocko@kernel.org>
To: Chris Down <chris@chrisdown.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>, Tejun Heo <tj@kernel.org>,
Roman Gushchin <guro@fb.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 5/6] mm, memcg: Prevent memory.swap.max load tearing
Date: Mon, 16 Mar 2020 15:58:59 +0100 [thread overview]
Message-ID: <20200316145859.GQ11482@dhcp22.suse.cz> (raw)
In-Reply-To: <bbec2c3d822217334855c8877a9d28b2a6d395fb.1584034301.git.chris@chrisdown.name>
On Thu 12-03-20 17:33:11, Chris Down wrote:
> The write side of this is xchg()/smp_mb(), so that's all good. Just a
> few sites missing a READ_ONCE.
>
> Signed-off-by: Chris Down <chris@chrisdown.name>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Roman Gushchin <guro@fb.com>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: linux-mm@kvack.org
> Cc: cgroups@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: kernel-team@fb.com
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> mm/memcontrol.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index e0ed790a2a8c..57048a38c75d 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1511,7 +1511,7 @@ void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
> if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
> pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
> K((u64)page_counter_read(&memcg->swap)),
> - K((u64)memcg->swap.max), memcg->swap.failcnt);
> + K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt);
> else {
> pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
> K((u64)page_counter_read(&memcg->memsw)),
> @@ -1544,7 +1544,7 @@ unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
> unsigned long swap_max;
>
> memsw_max = memcg->memsw.max;
> - swap_max = memcg->swap.max;
> + swap_max = READ_ONCE(memcg->swap.max);
> swap_max = min(swap_max, (unsigned long)total_swap_pages);
> max = min(max + swap_max, memsw_max);
> }
> @@ -7025,7 +7025,8 @@ bool mem_cgroup_swap_full(struct page *page)
> return false;
>
> for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
> - if (page_counter_read(&memcg->swap) * 2 >= memcg->swap.max)
> + if (page_counter_read(&memcg->swap) * 2 >=
> + READ_ONCE(memcg->swap.max))
> return true;
>
> return false;
> --
> 2.25.1
>
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-03-16 14:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-12 17:32 [PATCH 0/6] mm, memcg: cgroup v2 tunable load/store tearing fixes Chris Down
2020-03-12 17:32 ` [PATCH 1/6] mm, memcg: Prevent memory.high load/store tearing Chris Down
2020-03-16 14:54 ` Michal Hocko
2020-03-12 17:32 ` [PATCH 2/6] mm, memcg: Prevent memory.max load tearing Chris Down
2020-03-16 14:56 ` Michal Hocko
2020-03-12 17:33 ` [PATCH 3/6] mm, memcg: Prevent memory.low load/store tearing Chris Down
2020-03-16 14:57 ` Michal Hocko
2020-06-12 17:03 ` Michal Koutný
2020-06-12 17:13 ` Chris Down
2020-03-12 17:33 ` [PATCH 4/6] mm, memcg: Prevent memory.min " Chris Down
2020-03-16 14:58 ` Michal Hocko
2020-03-12 17:33 ` [PATCH 5/6] mm, memcg: Prevent memory.swap.max load tearing Chris Down
2020-03-16 14:58 ` Michal Hocko [this message]
2020-03-12 17:33 ` [PATCH 6/6] mm, memcg: Prevent mem_cgroup_protected store tearing Chris Down
2020-03-16 14:59 ` Michal Hocko
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