From: Michal Hocko <mhocko@suse.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Roman Gushchin" <guro@fb.com>,
"Shakeel Butt" <shakeelb@google.com>, "Tejun Heo" <tj@kernel.org>,
"Michal Koutný" <mkoutny@suse.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH] mm: memcontrol: switch to rstat fix
Date: Tue, 16 Mar 2021 10:30:54 +0100 [thread overview]
Message-ID: <YFB6zkqXx+Z+pO+q@dhcp22.suse.cz> (raw)
In-Reply-To: <20210315234100.64307-1-hannes@cmpxchg.org>
On Mon 15-03-21 19:41:00, Johannes Weiner wrote:
> Fix a sleep in atomic section problem: wb_writeback() takes a spinlock
> and calls wb_over_bg_thresh() -> mem_cgroup_wb_stats, but the regular
> rstat flushing function called from in there does lockbreaking and may
> sleep. Switch to the atomic variant, cgroup_rstat_irqsafe().
>
> To be consistent with other memcg flush calls, but without adding
> another memcg wrapper, inline and drop memcg_flush_vmstats() instead.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> mm/memcontrol.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index f7fb12d3c2fc..9091913ec877 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -757,11 +757,6 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
> return mz;
> }
>
> -static void memcg_flush_vmstats(struct mem_cgroup *memcg)
> -{
> - cgroup_rstat_flush(memcg->css.cgroup);
> -}
> -
> /**
> * __mod_memcg_state - update cgroup memory statistics
> * @memcg: the memory cgroup
> @@ -1572,7 +1567,7 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
> *
> * Current memory state:
> */
> - memcg_flush_vmstats(memcg);
> + cgroup_rstat_flush(memcg->css.cgroup);
>
> for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
> u64 size;
> @@ -3523,7 +3518,7 @@ static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
> unsigned long val;
>
> if (mem_cgroup_is_root(memcg)) {
> - memcg_flush_vmstats(memcg);
> + cgroup_rstat_flush(memcg->css.cgroup);
> val = memcg_page_state(memcg, NR_FILE_PAGES) +
> memcg_page_state(memcg, NR_ANON_MAPPED);
> if (swap)
> @@ -3925,7 +3920,7 @@ static int memcg_numa_stat_show(struct seq_file *m, void *v)
> int nid;
> struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
>
> - memcg_flush_vmstats(memcg);
> + cgroup_rstat_flush(memcg->css.cgroup);
>
> for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
> seq_printf(m, "%s=%lu", stat->name,
> @@ -3997,7 +3992,7 @@ static int memcg_stat_show(struct seq_file *m, void *v)
>
> BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
>
> - memcg_flush_vmstats(memcg);
> + cgroup_rstat_flush(memcg->css.cgroup);
>
> for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
> unsigned long nr;
> @@ -4500,7 +4495,7 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
> struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
> struct mem_cgroup *parent;
>
> - memcg_flush_vmstats(memcg);
> + cgroup_rstat_flush_irqsafe(memcg->css.cgroup);
>
> *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
> *pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
> --
> 2.30.1
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-03-16 9:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-15 23:41 [PATCH] mm: memcontrol: switch to rstat fix Johannes Weiner
2021-03-15 23:58 ` Shakeel Butt
2021-03-16 0:52 ` Singh, Balbir
2021-03-16 9:30 ` Michal Hocko [this message]
2021-03-17 19:19 ` Michal Koutný
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YFB6zkqXx+Z+pO+q@dhcp22.suse.cz \
--to=mhocko@suse.com \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=guro@fb.com \
--cc=hannes@cmpxchg.org \
--cc=kernel-team@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mkoutny@suse.com \
--cc=shakeelb@google.com \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).