From: Jan Kara <jack@suse.cz>
To: Hugh Dickins <hughd@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Mel Gorman <mel@csn.ul.ie>,
Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@infradead.org>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 12/15] writeback: remove writeback_control.more_io
Date: Wed, 13 Jul 2011 13:19:28 +0200 [thread overview]
Message-ID: <20110713111928.GA21787@quack.suse.cz> (raw)
In-Reply-To: <alpine.LSU.2.00.1107130350570.4184@sister.anvils>
On Wed 13-07-11 03:57:40, Hugh Dickins wrote:
> On Tue, 12 Jul 2011, Hugh Dickins wrote:
> > On Tue, 12 Jul 2011, Hugh Dickins wrote:
> > > On Mon, 11 Jul 2011, Wu Fengguang wrote:
> > > >
> > > > It's relatively easy to confirm, by reusing the below trace event to
> > > > show the inode (together with its state) being requeued.
> > > >
> > > > If this is the root cause, it may equally be fixed by
> > > >
> > > > - requeue_io(inode, wb);
> > > > + redirty_tail(inode, wb);
> > > >
> > > > which would be useful in case the bug is so deadly that it's no longer
> > > > possible to do tracing.
> > >
> > > I checked again this morning that I could reproduce it on two machines,
> > > one went in a few minutes, the other within the hour. Then I made that
> > > patch changing the requeue_io to redirty_tail, and left home with them
> > > running the test with the new kernel: we'll see at the end of the day
> > > how they fared.
> >
> > I think that fixes it. The x86_64 is still running with that, but the
> > ppc64 gave up fairly early, hitting freeze in __slab_free() instead.
> >
> > I've now, I believe, reconstituted what ChristophL intended from the
> > mm_types.h struct page patch he posted (which applied neither to mmotm,
> > nor to Pekka's for-next, so far as I could tell: maybe cl did some
> > intermediate tidying of some of the random indentation). So now
> > testing that with redirty_tail on ppc64: will report in 9 hours.
>
> Same result as before. The x86_64 is still going fine, but the ppc64
> again seized up in __slab_free() after two and a half hours of load.
>
> I think we should assume that your -requeue_io +redirty_tail is a good
> fix for the writeback freeze (if you can reassure us, that it does not
> risk postponing some writes indefinitely), and I move over to the other
> thread to pursue the struct page __slab_free() freeze.
Well, I_FREEING or I_WILL_FREE inodes are written back by iput_final()
and it is reclaim code that is responsible for eventually removing them. So
writeback code can safely ignore them. I_NEW inodes should move out of this
state when they are fully set up and in the writeback round following that,
we will consider them for writeback. So I think the change really makes
sense.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
next prev parent reply other threads:[~2011-07-13 11:19 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-07 21:32 [PATCH 00/15] writeback fixes and cleanups for 3.0 (v5) Wu Fengguang
2011-06-07 21:32 ` [PATCH 01/15] writeback: introduce .tagged_writepages for the WB_SYNC_NONE sync stage Wu Fengguang
2011-06-07 23:02 ` Andrew Morton
2011-06-07 23:24 ` Wu Fengguang
2011-06-07 21:32 ` [PATCH 02/15] writeback: update dirtied_when for synced inode to prevent livelock Wu Fengguang
2011-06-07 23:02 ` Andrew Morton
2011-06-07 23:51 ` Wu Fengguang
2011-06-07 21:32 ` [PATCH 03/15] writeback: introduce writeback_control.inodes_cleaned Wu Fengguang
2011-06-07 23:03 ` Andrew Morton
2011-06-08 0:10 ` Wu Fengguang
2011-06-07 21:32 ` [PATCH 04/15] writeback: try more writeback as long as something was written Wu Fengguang
2011-06-07 21:32 ` [PATCH 05/15] writeback: the kupdate expire timestamp should be a moving target Wu Fengguang
2011-06-07 21:32 ` [PATCH 06/15] writeback: refill b_io iff empty Wu Fengguang
2011-06-07 21:32 ` [PATCH 07/15] writeback: split inode_wb_list_lock into bdi_writeback.list_lock Wu Fengguang
2011-06-07 23:03 ` Andrew Morton
2011-06-08 0:20 ` Wu Fengguang
2011-06-08 0:35 ` Andrew Morton
2011-06-08 1:36 ` Wu Fengguang
2011-06-07 21:32 ` [PATCH 08/15] writeback: elevate queue_io() into wb_writeback() Wu Fengguang
2011-06-07 21:32 ` [PATCH 09/15] writeback: avoid extra sync work at enqueue time Wu Fengguang
2011-06-07 21:32 ` [PATCH 10/15] writeback: add bdi_dirty_limit() kernel-doc Wu Fengguang
2011-06-07 21:32 ` [PATCH 11/15] writeback: skip balance_dirty_pages() for in-memory fs Wu Fengguang
2011-06-11 13:07 ` Wu Fengguang
2011-06-13 13:42 ` Jan Kara
2011-06-07 21:32 ` [PATCH 12/15] writeback: remove writeback_control.more_io Wu Fengguang
2011-07-11 21:31 ` Hugh Dickins
2011-07-12 6:20 ` Wu Fengguang
2011-07-12 19:50 ` Hugh Dickins
2011-07-13 5:49 ` Hugh Dickins
2011-07-13 10:57 ` Hugh Dickins
2011-07-13 11:19 ` Jan Kara [this message]
2011-07-13 15:06 ` Hugh Dickins
2011-07-13 22:07 ` Wu Fengguang
2011-06-07 21:32 ` [PATCH 13/15] writeback: remove .nonblocking and .encountered_congestion Wu Fengguang
2011-06-07 21:32 ` [PATCH 14/15] writeback: trace event writeback_single_inode Wu Fengguang
2011-06-07 21:32 ` [PATCH 15/15] writeback: trace event writeback_queue_io Wu Fengguang
2011-06-07 23:04 ` [PATCH 00/15] writeback fixes and cleanups for 3.0 (v5) Andrew Morton
2011-06-08 2:01 ` Wu Fengguang
2011-06-08 6:21 ` Sedat Dilek
2011-06-08 13:45 ` Wu Fengguang
2011-06-09 1:16 ` Stephen Rothwell
2011-06-09 2:18 ` Wu Fengguang
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