From: Steven Whitehouse <swhiteho@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: torvalds@linux-foundation.org, mingo@elte.hu,
peterz@infradead.org, awalls@radix.net,
linux-kernel@vger.kernel.org, jeff@garzik.org,
akpm@linux-foundation.org, jens.axboe@oracle.com,
rusty@rustcorp.com.au, cl@linux-foundation.org,
dhowells@redhat.com, arjan@linux.intel.com, avi@redhat.com,
johannes@sipsolutions.net, andi@firstfloor.org
Subject: Re: [PATCH 39/40] gfs2: use workqueue instead of slow-work
Date: Mon, 18 Jan 2010 12:07:27 +0000 [thread overview]
Message-ID: <1263816447.2715.45.camel@localhost> (raw)
In-Reply-To: <4B5444FD.4050500@kernel.org>
Hi,
On Mon, 2010-01-18 at 20:24 +0900, Tejun Heo wrote:
> On 01/18/2010 06:45 PM, Steven Whitehouse wrote:
> > Hi,
> >
> > On Mon, 2010-01-18 at 09:57 +0900, Tejun Heo wrote:
> >> Workqueue can now handle high concurrency. Use system_long_wq instead
> >> of slow-work.
> >>
> >> Signed-off-by: Tejun Heo <tj@kernel.org>
> >> Cc: Steven Whitehouse <swhiteho@redhat.com>
> >
> > Acked-by: Steven Whitehouse <swhiteho@redhat.com> on two conditions:
> >
> > i) That scheduling work on this new workqueue will not require any
> > GFP_KERNEL allocations (even hidden ones such as starting new threads)
> > before the work runs. This is required since the recovery code must not
> > call into the fs until after its recovered.
>
> Oh, if that's the case, it needs its own wq with a rescuer. I thought
> the recovery path wasn't invoked during allocation. slow-work didn't
> guarantee such thing either. Anyways, changing that is pretty easy.
>
> Thanks.
>
Hmm, I thought I'd checked slow work pretty carefully before I decided
to use it :( Looking at it though, its pretty unlikely that it would
cause a problem. We can be 100% safe by just increasing the number of
slow work threads to one per mounted gfs2 fs (assuming no other slow
work users).
Even then it starts new threads by scheduling slow work and thus it
looks like recovery would run before the slow work to start a new
thread, so its much less likely to cause a problem than if the new
thread was started before the slow work item was executed. We haven't
seen a problem during testing so far.
Anyway, if its easy to solve that problem in the new code, thats all
good :-) Thanks for pointing out this issue,
Steve.
next prev parent reply other threads:[~2010-01-18 12:07 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-18 0:57 [PATCHSET] concurrency managed workqueue, take#3 Tejun Heo
2010-01-18 0:57 ` [PATCH 01/40] sched: consult online mask instead of active in select_fallback_rq() Tejun Heo
2010-01-18 10:13 ` Peter Zijlstra
2010-01-18 11:26 ` Tejun Heo
2010-01-18 0:57 ` [PATCH 02/40] sched: rename preempt_notifiers to sched_notifiers and refactor implementation Tejun Heo
2010-01-18 0:57 ` [PATCH 03/40] sched: refactor try_to_wake_up() Tejun Heo
2010-01-18 0:57 ` [PATCH 04/40] sched: implement __set_cpus_allowed() Tejun Heo
2010-01-18 9:56 ` Peter Zijlstra
2010-01-18 11:22 ` Tejun Heo
2010-01-18 11:41 ` Peter Zijlstra
2010-01-19 1:07 ` Tejun Heo
2010-01-19 8:37 ` Peter Zijlstra
2010-01-20 8:35 ` Tejun Heo
2010-01-20 8:50 ` Peter Zijlstra
2010-01-20 9:00 ` Tejun Heo
2010-01-20 8:59 ` Peter Zijlstra
2010-01-24 8:18 ` Tejun Heo
2010-01-18 0:57 ` [PATCH 05/40] sched: make sched_notifiers unconditional Tejun Heo
2010-01-18 0:57 ` [PATCH 06/40] sched: add wakeup/sleep sched_notifiers and allow NULL notifier ops Tejun Heo
2010-01-18 9:57 ` Peter Zijlstra
2010-01-18 11:31 ` Tejun Heo
2010-01-18 12:49 ` Peter Zijlstra
2010-01-19 1:04 ` Tejun Heo
2010-01-19 8:28 ` Tejun Heo
2010-01-19 8:55 ` Peter Zijlstra
2010-01-20 8:47 ` Tejun Heo
2010-01-18 0:57 ` [PATCH 07/40] sched: implement try_to_wake_up_local() Tejun Heo
2010-01-18 0:57 ` [PATCH 08/40] acpi: use queue_work_on() instead of binding workqueue worker to cpu0 Tejun Heo
2010-01-18 0:57 ` [PATCH 09/40] stop_machine: reimplement without using workqueue Tejun Heo
2010-01-18 0:57 ` [PATCH 10/40] workqueue: misc/cosmetic updates Tejun Heo
2010-01-18 0:57 ` [PATCH 11/40] workqueue: merge feature parameters into flags Tejun Heo
2010-01-18 0:57 ` [PATCH 12/40] workqueue: define both bit position and mask for work flags Tejun Heo
2010-01-18 0:57 ` [PATCH 13/40] workqueue: separate out process_one_work() Tejun Heo
2010-01-18 0:57 ` [PATCH 14/40] workqueue: temporarily disable workqueue tracing Tejun Heo
2010-01-18 0:57 ` [PATCH 15/40] workqueue: kill cpu_populated_map Tejun Heo
2010-01-18 0:57 ` [PATCH 16/40] workqueue: update cwq alignement Tejun Heo
2010-01-18 0:57 ` [PATCH 17/40] workqueue: reimplement workqueue flushing using color coded works Tejun Heo
2010-01-18 0:57 ` [PATCH 18/40] workqueue: introduce worker Tejun Heo
2010-01-18 0:57 ` [PATCH 19/40] workqueue: reimplement work flushing using linked works Tejun Heo
2010-01-18 0:57 ` [PATCH 20/40] workqueue: implement per-cwq active work limit Tejun Heo
2010-01-18 0:57 ` [PATCH 21/40] workqueue: reimplement workqueue freeze using max_active Tejun Heo
2010-01-18 0:57 ` [PATCH 22/40] workqueue: introduce global cwq and unify cwq locks Tejun Heo
2010-01-18 0:57 ` [PATCH 23/40] workqueue: implement worker states Tejun Heo
2010-01-18 0:57 ` [PATCH 24/40] workqueue: reimplement CPU hotplugging support using trustee Tejun Heo
2010-01-18 0:57 ` [PATCH 25/40] workqueue: make single thread workqueue shared worker pool friendly Tejun Heo
2010-01-18 0:57 ` [PATCH 26/40] workqueue: use shared worklist and pool all workers per cpu Tejun Heo
2010-01-18 0:57 ` [PATCH 27/40] workqueue: implement concurrency managed dynamic worker pool Tejun Heo
2010-01-18 0:57 ` [PATCH 28/40] workqueue: increase max_active of keventd and kill current_is_keventd() Tejun Heo
2010-01-18 0:57 ` [PATCH 29/40] workqueue: add system_wq and system_single_wq Tejun Heo
2010-01-18 0:57 ` [PATCH 30/40] workqueue: implement work_busy() Tejun Heo
2010-01-18 2:52 ` Andy Walls
2010-01-18 5:41 ` Tejun Heo
2010-01-18 0:57 ` [PATCH 31/40] libata: take advantage of cmwq and remove concurrency limitations Tejun Heo
2010-01-18 15:48 ` Stefan Richter
2010-01-19 0:49 ` Tejun Heo
2010-01-18 0:57 ` [PATCH 32/40] async: introduce workqueue based alternative implementation Tejun Heo
2010-01-18 6:01 ` Arjan van de Ven
2010-01-18 8:49 ` Tejun Heo
2010-01-18 15:25 ` Arjan van de Ven
2010-01-19 0:57 ` Tejun Heo
2010-01-19 0:57 ` Arjan van de Ven
2010-01-19 7:56 ` Tejun Heo
2010-01-19 14:37 ` Arjan van de Ven
2010-01-20 0:19 ` Tejun Heo
2010-01-20 0:31 ` Arjan van de Ven
2010-01-20 2:08 ` Tejun Heo
2010-01-20 6:03 ` Arjan van de Ven
2010-01-20 8:24 ` Tejun Heo
2010-01-22 10:59 ` [PATCH] async: use workqueue for worker pool Tejun Heo
2010-01-18 0:57 ` [PATCH 33/40] async: convert async users to use the new implementation Tejun Heo
2010-01-18 0:57 ` [PATCH 34/40] async: kill original implementation Tejun Heo
2010-01-18 0:57 ` [PATCH 35/40] fscache: convert object to use workqueue instead of slow-work Tejun Heo
2010-02-12 18:03 ` David Howells
2010-02-13 5:43 ` Tejun Heo
2010-02-15 15:04 ` David Howells
2010-02-16 3:40 ` Tejun Heo
2010-02-16 3:59 ` Tejun Heo
2010-02-16 18:05 ` David Howells
2010-02-16 23:50 ` Tejun Heo
2010-02-18 11:50 ` David Howells
2010-02-18 12:33 ` Tejun Heo
2010-01-18 0:57 ` [PATCH 36/40] fscache: convert operation " Tejun Heo
2010-01-18 0:57 ` [PATCH 37/40] fscache: drop references to slow-work Tejun Heo
2010-01-18 0:57 ` [PATCH 38/40] cifs: use workqueue instead of slow-work Tejun Heo
2010-01-19 12:20 ` Jeff Layton
2010-01-20 0:15 ` Tejun Heo
2010-01-20 0:56 ` Jeff Layton
2010-01-20 1:23 ` Tejun Heo
2010-01-22 11:14 ` [PATCH UPDATED " Tejun Heo
2010-01-22 11:45 ` Jeff Layton
2010-01-24 8:25 ` Tejun Heo
2010-01-24 12:13 ` Jeff Layton
2010-01-25 15:25 ` Tejun Heo
2010-01-18 0:57 ` [PATCH 39/40] gfs2: " Tejun Heo
2010-01-18 9:45 ` Steven Whitehouse
2010-01-18 11:24 ` Tejun Heo
2010-01-18 12:07 ` Steven Whitehouse [this message]
2010-01-19 1:00 ` Tejun Heo
2010-01-19 8:46 ` [PATCH UPDATED " Tejun Heo
2010-01-18 0:57 ` [PATCH 40/40] slow-work: kill it Tejun Heo
2010-01-18 1:03 ` perf-wq.c used to generate synthetic workload Tejun Heo
2010-01-18 16:13 ` [PATCHSET] concurrency managed workqueue, take#3 Stefan Richter
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=1263816447.2715.45.camel@localhost \
--to=swhiteho@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=andi@firstfloor.org \
--cc=arjan@linux.intel.com \
--cc=avi@redhat.com \
--cc=awalls@radix.net \
--cc=cl@linux-foundation.org \
--cc=dhowells@redhat.com \
--cc=jeff@garzik.org \
--cc=jens.axboe@oracle.com \
--cc=johannes@sipsolutions.net \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=peterz@infradead.org \
--cc=rusty@rustcorp.com.au \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.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