From: Michal Hocko <mhocko@suse.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: "Ricardo Cañuelo" <ricardo.canuelo@collabora.com>,
"Petr Mladek" <pmladek@suse.com>,
akpm@linux-foundation.org, kernel@collabora.com, hch@lst.de,
guro@fb.com, rientjes@google.com, mcgrof@kernel.org,
keescook@chromium.org, yzaikin@google.com, linux-mm@kvack.org,
"Sergey Senozhatsky" <sergey.senozhatsky@gmail.com>,
"Steven Rostedt" <rostedt@goodmis.org>
Subject: Re: [PATCH] mm, oom: enable rate-limiting controls for oom dumps
Date: Tue, 13 Oct 2020 09:25:02 +0200 [thread overview]
Message-ID: <20201013072411.GK29725@dhcp22.suse.cz> (raw)
In-Reply-To: <87993bef-3f83-0527-fa52-4f2c28eb7e56@i-love.sakura.ne.jp>
On Tue 13-10-20 09:40:27, Tetsuo Handa wrote:
> On 2020/10/13 0:41, Michal Hocko wrote:
> >> What about introducing some feedback from the printk code?
> >>
> >> static u64 printk_last_report_seq;
> >>
> >> if (consoles_seen(printk_last_report_seq)) {
> >> dump_header();
> >> printk_last_report_seq = printk_get_last_seq();
> >> }
> >>
> >> By other words. It would skip the massive report when the consoles
> >> were not able to see the previous one.
> >
> > I am pretty sure this has been discussed in the past but maybe we really
> > want to make ratelimit to work reasonably also for larger sections
> > instead. Current implementation only really works if the rate limited
> > operation is negligible wrt to the interval. Can we have a ratelimit
> > alternative with a scope effect (effectivelly lock like semantic)?
> > if (rate_limit_begin(&oom_rs)) {
> > dump_header();
> > rate_limit_end(&oom_rs);
> > }
> >
> > rate_limi_begin would act like a try lock with additional constrain on
> > the period/cadence based on rate_limi_end marked values.
> >
>
> Here is one of past discussions.
>
> https://lkml.kernel.org/r/7de2310d-afbd-e616-e83a-d75103b986c6@i-love.sakura.ne.jp
> https://lkml.kernel.org/r/20190830103504.GA28313@dhcp22.suse.cz
> https://lkml.kernel.org/r/57be50b2-a97a-e559-e4bd-10d923895f83@i-love.sakura.ne.jp
>
> Michal Hocko complained about different OOM domains, and now just ignores it...
None of the above deals with the amount of printed data which is the
point of this patch AFAIU.
> Proper ratelimiting for OOM messages had better not to count on asynchronous printk().
Because?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-10-13 7:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 9:30 [PATCH] mm, oom: enable rate-limiting controls for oom dumps Ricardo Cañuelo
2020-10-12 15:18 ` Michal Hocko
2020-10-13 9:23 ` Ricardo Cañuelo
2020-10-13 11:56 ` Michal Hocko
2020-10-12 15:22 ` Petr Mladek
2020-10-12 15:41 ` Michal Hocko
2020-10-13 0:40 ` Tetsuo Handa
2020-10-13 7:25 ` Michal Hocko [this message]
2020-10-13 9:02 ` Petr Mladek
2020-10-13 10:46 ` Tetsuo Handa
2020-10-15 13:05 ` Petr Mladek
2020-10-13 9:18 ` Ricardo Cañuelo
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