From: Christoph Hellwig <hch@infradead.org>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"bugzilla-daemon@bugzilla.kernel.org"
<bugzilla-daemon@bugzilla.kernel.org>,
"daaugusto@gmail.com" <daaugusto@gmail.com>,
"kernel-bugzilla@cygnusx-1.org" <kernel-bugzilla@cygnusx-1.org>,
"listposter@gmail.com" <listposter@gmail.com>,
"justincase@yopmail.com" <justincase@yopmail.com>,
"clopez@igalia.com" <clopez@igalia.com>, Tao Ma <tm@tao.ma>,
Jens Axboe <axboe@kernel.dk>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [Bug 18632] "INFO: task" dpkg "blocked for more than 120 seconds.
Date: Thu, 9 Jun 2011 08:17:42 -0400 [thread overview]
Message-ID: <20110609121742.GA29569@infradead.org> (raw)
In-Reply-To: <20110609121117.GA5768@localhost>
On Thu, Jun 09, 2011 at 08:11:17PM +0800, Wu Fengguang wrote:
> > This waits for the I/O completion to actually arrive - something that
> > XFS does correctly in both sync and fsync, but ext4 only does for fsync.
>
> Will it benefit to flush the disk _once_ at the end of sync?
> (perhaps it's not be as easy in complex storage setups or whatever)
XFS currently does it's own passes over data and metadata in sync. To
some extent they are overkill, but things like the iowait that's
prominent in your trace actually is needed to catch all in-flight
direct I/O.
> It's definitely a problem that cfq delays async writes too much.
> However in Carlos's report,
>
> https://bugzilla.kernel.org/attachment.cgi?id=61222
>
> there are no sync(1) or fsync running at all. So it may be indicating
> a different problem.
If you have a heavy read load we still need to write back timestamps,
and it kinda sounds like he's hitting that. No guarantee that actuall
is the cause, though.
next prev parent reply other threads:[~2011-06-09 12:17 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-18632-27@https.bugzilla.kernel.org/>
[not found] ` <201106082138.p58Lchgj002615@demeter2.kernel.org>
[not found] ` <20110608150241.8412a63d.akpm@linux-foundation.org>
2011-06-09 3:32 ` [Bug 18632] "INFO: task" dpkg "blocked for more than 120 seconds Wu Fengguang
2011-06-09 3:54 ` Wu Fengguang
2011-06-09 8:27 ` Christoph Hellwig
2011-06-09 9:09 ` Wu Fengguang
2011-06-09 11:02 ` Christoph Hellwig
2011-06-09 12:11 ` Wu Fengguang
2011-06-09 12:17 ` Wu Fengguang
2011-06-09 12:17 ` Christoph Hellwig [this message]
2011-06-09 12:43 ` Wu Fengguang
2011-06-09 13:23 ` Christoph Hellwig
2011-06-10 3:21 ` Wu Fengguang
2011-06-19 15:56 ` Christoph Hellwig
2011-06-19 16:33 ` Wu Fengguang
2011-06-09 13:56 ` Tao Ma
2011-06-09 14:12 ` Tao Ma
2011-06-09 14:21 ` Christoph Hellwig
2011-06-09 14:32 ` Vivek Goyal
2011-06-09 14:51 ` Tao Ma
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=20110609121742.GA29569@infradead.org \
--to=hch@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=bugzilla-daemon@bugzilla.kernel.org \
--cc=clopez@igalia.com \
--cc=daaugusto@gmail.com \
--cc=david@fromorbit.com \
--cc=fengguang.wu@intel.com \
--cc=jack@suse.cz \
--cc=justincase@yopmail.com \
--cc=kernel-bugzilla@cygnusx-1.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=listposter@gmail.com \
--cc=tm@tao.ma \
--cc=vgoyal@redhat.com \
/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).