From: Steven Rostedt <rostedt@goodmis.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: vnagarnaik@google.com, mingo@redhat.com, fweisbec@gmail.com,
mrubin@google.com, dhsharp@google.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] trace: Set __GFP_NORETRY flag for ring buffer allocating process
Date: Thu, 09 Jun 2011 08:14:28 -0400 [thread overview]
Message-ID: <1307621668.9218.37.camel@gandalf.stny.rr.com> (raw)
In-Reply-To: <4DF0B097.7010805@jp.fujitsu.com>
On Thu, 2011-06-09 at 20:37 +0900, KOSAKI Motohiro wrote:
> Unfortunately, __GFP_NORETRY is racy and don't work as expected.
> If free memory is not enough, the thread may start to reclaim and
> another thread can steal the reclaimed memory. And thread0 don't retry.
>
> Then, thread0's alloc page may fail even though system have enough reclaimable
> memory.
>
> thread0 thread1
> ---------------------------------------------------------------
> alloc_pages()
> get_page_from_freelist() -> fail
> try_to_free_pages()
> alloc_pages()
> get_page_from_freelist() -> success
> get_page_from_freelist() -> fail again
>
> I think this is mm issue, and afaik, Minchan and some developers are
> working on fixing it. but _now_ your patch doesn't work.
Have you seen this fail in practice?
I'm not too concern if it only triggers when memory is tight. But if it
is triggering on normal cases, then that worries me.
Thanks,
-- Steve
next prev parent reply other threads:[~2011-06-09 12:14 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-26 19:52 [PATCH] trace: Set oom_score_adj to maximum for ring buffer allocating process Vaibhav Nagarnaik
2011-05-26 20:04 ` Steven Rostedt
2011-05-26 20:22 ` David Rientjes
2011-05-26 20:23 ` Vaibhav Nagarnaik
2011-05-26 20:33 ` David Rientjes
2011-05-26 21:00 ` Steven Rostedt
2011-05-26 22:28 ` Vaibhav Nagarnaik
2011-05-26 23:38 ` Steven Rostedt
2011-05-27 9:43 ` David Rientjes
2011-05-27 12:48 ` Steven Rostedt
2011-05-26 23:23 ` Vaibhav Nagarnaik
2011-05-27 17:58 ` Vaibhav Nagarnaik
2011-05-27 23:22 ` David Rientjes
2011-05-28 0:44 ` Vaibhav Nagarnaik
2011-05-28 1:50 ` Steven Rostedt
2011-05-30 6:23 ` KOSAKI Motohiro
2011-05-30 23:54 ` Vaibhav Nagarnaik
2011-05-30 23:46 ` Vaibhav Nagarnaik
2011-06-07 23:07 ` Steven Rostedt
2011-06-07 23:30 ` Vaibhav Nagarnaik
2011-06-07 23:41 ` [PATCH] trace: Set __GFP_NORETRY flag " Vaibhav Nagarnaik
2011-06-07 23:47 ` Frederic Weisbecker
2011-06-08 0:01 ` [PATCH v2] " Vaibhav Nagarnaik
2011-06-08 2:30 ` David Rientjes
2011-06-09 11:37 ` KOSAKI Motohiro
2011-06-09 12:14 ` Steven Rostedt [this message]
2011-06-09 18:41 ` Vaibhav Nagarnaik
2011-06-09 19:42 ` David Rientjes
2011-06-09 19:52 ` Steven Rostedt
2011-07-05 12:54 ` [tip:perf/core] ring-buffer: " tip-bot for Vaibhav Nagarnaik
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