From: Dave Jones <davej@redhat.com>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: linux-mm@kvack.org, Linux Kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>,
linux-fsdevel@vger.kernel.org
Subject: Re: livelock in __writeback_inodes_wb ?
Date: Tue, 11 Dec 2012 09:29:42 -0500 [thread overview]
Message-ID: <20121211142942.GA1943@redhat.com> (raw)
In-Reply-To: <20121211082327.GA15706@localhost>
On Tue, Dec 11, 2012 at 04:23:27PM +0800, Fengguang Wu wrote:
> On Wed, Nov 28, 2012 at 09:55:15AM -0500, Dave Jones wrote:
> > We had a user report the soft lockup detector kicked after 22
> > seconds of no progress, with this trace..
>
> Where is the original report? The reporter may help provide some clues
> on the workload that triggered the bug.
https://bugzilla.redhat.com/show_bug.cgi?id=880949
> The bug reporter should know best whether there are heavy IO.
>
> However I suspect it's not directly caused by heavy IO: we will
> release &wb->list_lock before each __writeback_single_inode() call,
> which starts writeback IO for each inode.
>
> > Should there be something in this loop periodically poking
> > the watchdog perhaps ?
>
> It seems we failed to release &wb->list_lock in wb_writeback() for
> long time (dozens of seconds). That is, the inode_sleep_on_writeback()
> is somehow not called. However it's not obvious to me how come this
> can happen..
Right, it seems that we only drop the lock when there is more work to do.
And if there is no work to do, then we would have bailed from the loop.
mysterious.
Dave
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2012-12-11 14:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-28 14:55 livelock in __writeback_inodes_wb ? Dave Jones
2012-12-11 8:23 ` Fengguang Wu
2012-12-11 13:41 ` Jan Kara
2012-12-14 9:13 ` Fengguang Wu
2012-12-11 14:29 ` Dave Jones [this message]
2012-12-12 2:26 ` Simon Jeons
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121211142942.GA1943@redhat.com \
--to=davej@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=fengguang.wu@intel.com \
--cc=jack@suse.cz \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).