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From: Eric Wong <normalperson@yhbt.net>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>,
	linux-mm@kvack.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, Rik van Riel <riel@redhat.com>,
	Minchan Kim <minchan@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: ppoll() stuck on POLLIN while TCP peer is sending
Date: Thu, 3 Jan 2013 18:32:51 +0000	[thread overview]
Message-ID: <20130103183251.GA10113@dcvr.yhbt.net> (raw)
In-Reply-To: <1357220469.21409.24574.camel@edumazet-glaptop>

Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Wed, 2013-01-02 at 20:47 +0000, Eric Wong wrote:
> > Eric Wong <normalperson@yhbt.net> wrote:
> > > [1] my full setup is very strange.
> > > 
> > >     Other than the FUSE component I forgot to mention, little depends on
> > >     the kernel.  With all this, the standalone toosleepy can get stuck.
> > >     I'll try to reproduce it with less...
> > 
> > I just confirmed my toosleepy processes will get stuck while just
> > doing "rsync -a" between local disks.  So this does not depend on
> > sendfile or FUSE to reproduce.
> > --
> 
> How do you tell your 'toosleepy' is stuck ?

My original post showed it stuck with strace (in ppoll + send).
I only strace after seeing it's not using any CPU in top.

http://mid.gmane.org/20121228014503.GA5017@dcvr.yhbt.net
(lsof also confirmed the ppoll/send sockets were peers)

> If reading its output, you should change its logic, there is no
> guarantee the recv() will deliver exactly 16384 bytes each round.
> 
> With the following patch, I cant reproduce the 'apparent stuck'

Right, the output is just an approximation and the logic there
was bogus.

Thanks for looking at this.

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  reply	other threads:[~2013-01-03 18:32 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20121228014503.GA5017@dcvr.yhbt.net>
2013-01-02 20:08 ` Eric Wong
2013-01-02 20:47   ` Eric Wong
2013-01-03 13:41     ` Eric Dumazet
2013-01-03 18:32       ` Eric Wong [this message]
2013-01-03 23:45         ` Eric Wong
2013-01-04  0:26           ` Eric Wong
2013-01-04  3:52             ` Eric Wong
2013-01-04 16:01   ` Mel Gorman
2013-01-04 17:15     ` Eric Dumazet
2013-01-04 17:59     ` Eric Wong
2013-01-05  1:07     ` Eric Wong
2013-01-06 12:07     ` Eric Wong
2013-01-07 12:25       ` Mel Gorman
2013-01-07 22:38         ` Eric Dumazet
2013-01-08  0:21           ` Eric Wong
2013-01-07 22:38         ` Eric Wong
2013-01-08 20:14           ` Eric Wong
2013-01-08 22:43           ` Mel Gorman
2013-01-08 23:23             ` Eric Wong
2013-01-09  2:14               ` Eric Dumazet
2013-01-09  2:32                 ` Eric Dumazet
2013-01-09  2:54                   ` Eric Dumazet
2013-01-09  3:55                     ` Eric Wong
2013-01-09  8:42                       ` Eric Wong
2013-01-09  8:51                         ` Eric Wong
2013-01-09 13:42                   ` Mel Gorman
2013-01-09 13:37               ` Mel Gorman
2013-01-09 13:50                 ` Mel Gorman
2013-01-10  9:25                 ` Eric Wong
2013-01-10 19:42                   ` Mel Gorman
2013-01-10 20:03                     ` Eric Wong
2013-01-10 20:58                     ` Eric Dumazet
2013-01-11  0:51                     ` Eric Wong
2013-01-11  9:30                       ` Mel Gorman
2013-01-09 21:29             ` Eric Wong

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