public inbox for linux-xfs@vger.kernel.org
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: Eric Sandeen <sandeen@redhat.com>, xfs-oss <xfs@oss.sgi.com>
Subject: Re: [PATCH 2/2] xfs: mark the xfs-alloc workqueue as high priority
Date: Sun, 11 Jan 2015 01:33:12 -0500	[thread overview]
Message-ID: <20150111063312.GA3984@htj.dyndns.org> (raw)
In-Reply-To: <54B1BE0E.7020302@sandeen.net>

Hello,

On Sat, Jan 10, 2015 at 06:04:30PM -0600, Eric Sandeen wrote:
> > The only reasons that work item would stay there are
> > 
> > * The rescuer is already executing something else from that workqueue
> >   and that one is stuck.
> 
> I'll have to look at that.  I hope I still have access to the core...

Yes, if this is happening, the rescuer worker which has the name of
the workqueue would be stuck somewhere.

> > * The worker pool is still considered to be making forward progress -
> >   there's a worker which isn't blocked and can burn CPU cycles.
> 
> AFAICT, the first thing in the pool is the xffs_end_io blocked waiting for the ilock.
> 
> I assume it's only the first one that matters?

Whatever work item which is executing on that pool on that CPU.
Checking the tasks which are runnable on that CPU should show it.

> > Again, if xfs is using workqueue correctly, that work item shouldn't
> > get stuck at all.  What other workqueues are doing is irrelevant.
> 
> and yet here we are; one of us must be missing something.  It's quite
> possibly me :) but we definitely have this thing wedged, and moving
> the xfsalloc item to the front via high priority did solve it.  Not saying
> it's the right solution, just a data point.

It sure is possible that workqueue is misbehaving but I'm pretty
doubtful that it'd be, especially given that xfs issue has been around
for quite a while, which excludes recent regressions in the rescuer
logic, and that there hasn't been any other case of failed forward
progress guarantee.

Thanks.

-- 
tejun

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

  reply	other threads:[~2015-01-11  6:33 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-09 18:08 [PATCH 0/2] xfs: make xfs allocation workqueue per-mount, and high priority Eric Sandeen
2015-01-09 18:10 ` [PATCH 1/2] xfs: make global xfsalloc workqueue per-mount Eric Sandeen
2015-01-12 15:35   ` Brian Foster
2015-01-09 18:12 ` [PATCH 2/2] xfs: mark the xfs-alloc workqueue as high priority Eric Sandeen
2015-01-09 18:23   ` Tejun Heo
2015-01-09 20:36     ` Eric Sandeen
2015-01-10 19:28       ` Tejun Heo
2015-01-11  0:04         ` Eric Sandeen
2015-01-11  6:33           ` Tejun Heo [this message]
2015-01-12 20:09         ` Eric Sandeen
2015-01-12 22:53           ` Tejun Heo
2015-01-12 23:12             ` Eric Sandeen
2015-01-12 23:37               ` Tejun Heo
2015-01-13 19:08                 ` Eric Sandeen
2015-01-13 20:19                   ` Tejun Heo
2015-01-13 20:29                     ` Eric Sandeen
2015-01-13 20:46                       ` Tejun Heo
2015-01-13 22:58                         ` Eric Sandeen
2015-01-13 23:35                           ` [PATCH wq/for-3.19] workqueue: fix subtle pool management issue which can stall whole worker_pool Tejun Heo
2015-01-16 19:32                             ` [PATCH workqueue wq/for-3.19-fixes] " Tejun Heo
2015-01-19  2:15                               ` Lai Jiangshan
2015-01-09 23:28     ` [PATCH 2/2] xfs: mark the xfs-alloc workqueue as high priority Dave Chinner
2015-01-10 17:41       ` Tejun Heo
2015-01-12  3:30         ` Dave Chinner
2015-01-13 20:50           ` Tejun Heo

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=20150111063312.GA3984@htj.dyndns.org \
    --to=tj@kernel.org \
    --cc=sandeen@redhat.com \
    --cc=sandeen@sandeen.net \
    --cc=xfs@oss.sgi.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