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From: Jan Kara <jack@suse.cz>
To: snazy@snazy.de
Cc: Jan Kara <jack@suse.cz>, Johannes Weiner <hannes@cmpxchg.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Michal Hocko <mhocko@kernel.org>,
	Josef Bacik <josef@toxicpanda.com>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	Randy Dunlap <rdunlap@infradead.org>,
	linux-kernel@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Potyra, Stefan" <Stefan.Potyra@elektrobit.com>
Subject: Re: mlockall(MCL_CURRENT) blocking infinitely
Date: Wed, 6 Nov 2019 15:35:37 +0100	[thread overview]
Message-ID: <20191106143537.GI16085@quack2.suse.cz> (raw)
In-Reply-To: <4edf4dea97f6c1e3c7d4fed0e12c3dc6dff7575f.camel@gmx.de>

On Wed 06-11-19 14:45:43, Robert Stupp wrote:
> On Wed, 2019-11-06 at 13:03 +0100, Jan Kara wrote:
> > On Tue 05-11-19 13:22:11, Johannes Weiner wrote:
> > > What I don't quite understand yet is why the fault path doesn't
> > > make
> > > progress eventually. We must drop the mmap_sem without changing the
> > > state in any way. How can we keep looping on the same page?
> >
> > That may be a slight suboptimality with Josef's patches. If the page
> > is marked as PageReadahead, we always drop mmap_sem if we can and
> > start
> > readahead without checking whether that makes sense or not in
> > do_async_mmap_readahead(). OTOH page_cache_async_readahead() then
> > clears
> > PageReadahead so the only way how I can see we could loop like this
> > is when
> > file->ra->ra_pages is 0. Not sure if that's what's happening through.
> > We'd
> > need to find which of the paths in filemap_fault() calls
> > maybe_unlock_mmap_for_io() to tell more.
> 
> Yes, ra_pages==0

OK, thanks for confirmation!

> 5637e22a2000-5637e22a3000 r--p 00000000 103:02 49172550                  /home/snazy/devel/misc/zzz/test

What kind of device & fs does your /home stay on? I don't recognize the major
number...

							Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

  reply	other threads:[~2019-11-06 14:35 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-24  7:36 mlockall(MCL_CURRENT) blocking infinitely Robert Stupp
2019-10-24 23:34 ` Randy Dunlap
2019-10-25  9:21   ` Michal Hocko
2019-10-25 11:02     ` Robert Stupp
2019-10-25 11:02       ` Robert Stupp
2019-10-25 11:46       ` Michal Hocko
2019-10-25 11:50         ` Michal Hocko
2019-10-25 11:59           ` Robert Stupp
2019-10-25 11:59             ` Robert Stupp
2019-10-25 13:19             ` Robert Stupp
2019-10-25 13:19               ` Robert Stupp
2019-10-25 11:55         ` Robert Stupp
2019-10-25 11:55           ` Robert Stupp
2019-10-25 12:05           ` Michal Hocko
2019-10-25 12:11             ` Michal Hocko
2019-10-25 13:10               ` Robert Stupp
2019-10-25 13:10                 ` Robert Stupp
2019-10-25 13:27                 ` Michal Hocko
2019-10-25 13:45                   ` Robert Stupp
2019-10-25 13:45                     ` Robert Stupp
2019-10-25 13:57                     ` Michal Hocko
2019-10-25 14:00                       ` Michal Hocko
2019-10-25 15:58                         ` Robert Stupp
2019-10-25 15:58                           ` Robert Stupp
2019-11-05 13:23                           ` Robert Stupp
2019-11-05 13:23                             ` Robert Stupp
2019-11-05 15:28                             ` Vlastimil Babka
2019-11-05 18:22                               ` Johannes Weiner
2019-11-05 20:05                                 ` Robert Stupp
2019-11-05 20:05                                   ` Robert Stupp
2019-11-06 10:25                                   ` Robert Stupp
2019-11-06 10:25                                     ` Robert Stupp
2019-11-06 11:26                                     ` Robert Stupp
2019-11-06 11:26                                       ` Robert Stupp
2019-11-06 12:04                                       ` Jan Kara
2019-11-06 12:24                                       ` Robert Stupp
2019-11-06 12:24                                         ` Robert Stupp
2019-11-06 12:03                                 ` Jan Kara
2019-11-06 13:45                                   ` Robert Stupp
2019-11-06 13:45                                     ` Robert Stupp
2019-11-06 14:35                                     ` Jan Kara [this message]
2019-11-06 15:32                                       ` Robert Stupp
2019-11-06 15:32                                         ` Robert Stupp
2019-11-06 14:38                                     ` Jan Kara
2019-11-06 14:56                                     ` Josef Bacik
2019-11-06 15:05                                       ` Jan Kara
2019-11-06 15:14                                         ` Josef Bacik
2019-11-06 15:25                                           ` Jan Kara
2019-11-06 16:39                                           ` Robert Stupp
2019-11-06 16:39                                             ` Robert Stupp
2019-11-06 17:03                                             ` Robert Stupp
2019-11-06 17:03                                               ` Robert Stupp
2019-11-06 17:25                                               ` Jan Kara
2019-11-07  8:08                                                 ` Robert Stupp
2019-11-07  8:08                                                   ` Robert Stupp
2019-11-20 12:42                                                   ` Robert Stupp
2019-10-25 13:55                   ` Robert Stupp
2019-10-25 13:55                     ` Robert Stupp

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