From: Jeff Garzik <jgarzik@pobox.com>
To: Tejun Heo <tj@kernel.org>
Cc: torvalds@linux-foundation.org, mingo@elte.hu,
linux-kernel@vger.kernel.org, jeff@garzik.org,
akpm@linux-foundation.org, rusty@rustcorp.com.au,
cl@linux-foundation.org, dhowells@redhat.com,
arjan@linux.intel.com, oleg@redhat.com, axboe@kernel.dk,
fweisbec@gmail.com, dwalker@codeaurora.org,
stefanr@s5r6.in-berlin.de, florian@mickler.org,
andi@firstfloor.org, mst@redhat.com, randy.dunlap@oracle.com
Subject: Re: [PATCH 33/35] libata: take advantage of cmwq and remove concurrency limitations
Date: Mon, 28 Jun 2010 18:32:40 -0400 [thread overview]
Message-ID: <4C292308.4050906@pobox.com> (raw)
In-Reply-To: <1277759063-24607-34-git-send-email-tj@kernel.org>
On 06/28/2010 05:04 PM, Tejun Heo wrote:
> libata has two concurrency related limitations.
>
> a. ata_wq which is used for polling PIO has single thread per CPU. If
> there are multiple devices doing polling PIO on the same CPU, they
> can't be executed simultaneously.
>
> b. ata_aux_wq which is used for SCSI probing has single thread. In
> cases where SCSI probing is stalled for extended period of time
> which is possible for ATAPI devices, this will stall all probing.
>
> #a is solved by increasing maximum concurrency of ata_wq. Please note
> that polling PIO might be used under allocation path and thus needs to
> be served by a separate wq with a rescuer.
>
> #b is solved by using the default wq instead and achieving exclusion
> via per-port mutex.
>
> Signed-off-by: Tejun Heo<tj@kernel.org>
> Cc: Jeff Garzik<jgarzik@pobox.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
next prev parent reply other threads:[~2010-06-28 22:32 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-28 21:03 [PATCHSET] workqueue: concurrency managed workqueue, take#6 Tejun Heo
2010-06-28 21:03 ` [PATCH 01/35] kthread: implement kthread_worker Tejun Heo
2010-06-28 21:03 ` [PATCH 02/35] ivtv: use kthread_worker instead of workqueue Tejun Heo
2010-07-05 17:11 ` Andy Walls
2010-07-06 7:01 ` Tejun Heo
2010-07-09 13:15 ` Andy Walls
2010-06-28 21:03 ` [PATCH 03/35] kthread: implement kthread_data() Tejun Heo
2010-06-28 21:03 ` [PATCH 04/35] acpi: use queue_work_on() instead of binding workqueue worker to cpu0 Tejun Heo
2010-06-28 21:03 ` [PATCH 05/35] workqueue: kill RT workqueue Tejun Heo
2010-06-28 21:03 ` [PATCH 06/35] workqueue: misc/cosmetic updates Tejun Heo
2010-06-28 21:03 ` [PATCH 07/35] workqueue: merge feature parameters into flags Tejun Heo
2010-06-28 21:03 ` [PATCH 08/35] workqueue: define masks for work flags and conditionalize STATIC flags Tejun Heo
2010-06-28 21:03 ` [PATCH 09/35] workqueue: separate out process_one_work() Tejun Heo
2010-06-28 21:03 ` [PATCH 10/35] workqueue: temporarily remove workqueue tracing Tejun Heo
2010-06-28 21:03 ` [PATCH 11/35] workqueue: kill cpu_populated_map Tejun Heo
2010-06-28 21:04 ` [PATCH 12/35] workqueue: update cwq alignement Tejun Heo
2010-06-28 22:47 ` Frederic Weisbecker
2010-06-29 7:39 ` Tejun Heo
2010-06-29 12:36 ` Frederic Weisbecker
2010-06-29 15:42 ` Tejun Heo
2010-06-29 15:47 ` Frederic Weisbecker
2010-06-29 15:51 ` Tejun Heo
2010-06-29 16:01 ` Frederic Weisbecker
2010-06-29 16:09 ` Tejun Heo
2010-06-29 16:17 ` Frederic Weisbecker
2010-07-06 14:22 ` Christoph Lameter
2010-07-06 14:26 ` Tejun Heo
2010-06-29 8:12 ` [PATCH UPDATED " Tejun Heo
2010-06-29 13:39 ` Frederic Weisbecker
2010-06-28 21:04 ` [PATCH 13/35] workqueue: reimplement workqueue flushing using color coded works Tejun Heo
2010-06-28 21:04 ` [PATCH 14/35] workqueue: introduce worker Tejun Heo
2010-06-28 21:04 ` [PATCH 15/35] workqueue: reimplement work flushing using linked works Tejun Heo
2010-06-28 21:04 ` [PATCH 16/35] workqueue: implement per-cwq active work limit Tejun Heo
2010-06-28 21:04 ` [PATCH 17/35] workqueue: reimplement workqueue freeze using max_active Tejun Heo
2010-06-28 21:04 ` [PATCH 18/35] workqueue: introduce global cwq and unify cwq locks Tejun Heo
2010-06-28 21:04 ` [PATCH 19/35] workqueue: implement worker states Tejun Heo
2010-06-28 21:04 ` [PATCH 20/35] workqueue: reimplement CPU hotplugging support using trustee Tejun Heo
2010-06-28 21:04 ` [PATCH 21/35] workqueue: make single thread workqueue shared worker pool friendly Tejun Heo
2010-06-28 21:04 ` [PATCH 22/35] workqueue: add find_worker_executing_work() and track current_cwq Tejun Heo
2010-06-28 21:04 ` [PATCH 23/35] workqueue: carry cpu number in work data once execution starts Tejun Heo
2010-06-28 21:04 ` [PATCH 24/35] workqueue: implement WQ_NON_REENTRANT Tejun Heo
2010-06-28 21:04 ` [PATCH 25/35] workqueue: use shared worklist and pool all workers per cpu Tejun Heo
2010-06-28 21:04 ` [PATCH 26/35] workqueue: implement worker_{set|clr}_flags() Tejun Heo
2010-06-28 21:04 ` [PATCH 27/35] workqueue: implement concurrency managed dynamic worker pool Tejun Heo
2010-07-09 9:11 ` Yong Zhang
2010-07-12 8:53 ` [PATCH] workqueue: fix locking in retry path of maybe_create_worker() Tejun Heo
2010-07-12 13:23 ` Yong Zhang
2010-07-14 9:37 ` Tejun Heo
2010-06-28 21:04 ` [PATCH 28/35] workqueue: increase max_active of keventd and kill current_is_keventd() Tejun Heo
2010-06-28 21:04 ` [PATCH 29/35] workqueue: s/__create_workqueue()/alloc_workqueue()/, and add system workqueues Tejun Heo
2010-06-28 21:04 ` [PATCH 30/35] workqueue: implement several utility APIs Tejun Heo
2010-06-28 21:04 ` [PATCH 31/35] workqueue: implement high priority workqueue Tejun Heo
2010-06-28 21:04 ` [PATCH 32/35] workqueue: implement cpu intensive workqueue Tejun Heo
2010-06-28 21:04 ` [PATCH 33/35] libata: take advantage of cmwq and remove concurrency limitations Tejun Heo
2010-06-28 22:32 ` Jeff Garzik [this message]
2010-06-29 7:00 ` Tejun Heo
2010-06-28 21:04 ` [PATCH 34/35] async: use workqueue for worker pool Tejun Heo
2010-06-28 22:55 ` Frederic Weisbecker
2010-06-29 7:25 ` Tejun Heo
2010-06-29 12:18 ` Frederic Weisbecker
2010-06-29 15:46 ` Tejun Heo
2010-06-29 15:52 ` Frederic Weisbecker
2010-06-29 15:55 ` Tejun Heo
2010-06-29 16:40 ` Arjan van de Ven
2010-06-29 16:59 ` Tejun Heo
2010-06-29 17:12 ` Tejun Heo
2010-06-29 18:08 ` Arjan van de Ven
2010-06-29 18:07 ` Arjan van de Ven
2010-06-29 18:15 ` Tejun Heo
2010-06-29 18:22 ` Arjan van de Ven
2010-06-29 18:34 ` Tejun Heo
2010-06-29 18:41 ` Arjan van de Ven
2010-06-29 18:59 ` Tejun Heo
2010-06-29 21:37 ` David Howells
2010-07-02 9:17 ` [PATCHSET] workqueue: implement and use WQ_UNBOUND Tejun Heo
2010-07-02 9:19 ` [PATCH 1/4] workqueue: prepare for WQ_UNBOUND implementation Tejun Heo
2010-07-02 9:24 ` [PATCH 3/4] workqueue: remove WQ_SINGLE_CPU and use WQ_UNBOUND instead Tejun Heo
2010-07-02 9:25 ` [PATCH 4/4] async: use workqueue for worker pool Tejun Heo
2010-07-02 15:09 ` Stefan Richter
2010-07-02 16:26 ` Tejun Heo
2010-07-02 16:25 ` [PATCH UPDATED " Tejun Heo
2010-07-02 9:28 ` [PATCH 2/4] workqueue: implement unbound workqueue Tejun Heo
2010-07-02 9:32 ` [PATCHSET] workqueue: implement and use WQ_UNBOUND Tejun Heo
2010-07-07 5:41 ` Tejun Heo
2010-07-14 9:39 ` Tejun Heo
2010-07-20 22:01 ` David Howells
2010-07-02 9:20 ` [PATCH 2/4] workqueue: implement unbound workqueue Tejun Heo
2010-06-28 21:04 ` [PATCH 35/35] pcrypt: use HIGHPRI and CPU_INTENSIVE workqueues for padata Tejun Heo
2010-06-28 23:18 ` [PATCHSET] workqueue: concurrency managed workqueue, take#6 Frederic Weisbecker
2010-06-29 7:05 ` Tejun Heo
2010-07-02 8:32 ` [PATCHSET] workqueue: fixes on top of cmwq take#6 Tejun Heo
2010-07-02 8:33 ` [PATCH 1/4] workqueue: use worker_set/clr_flags() only from worker itself Tejun Heo
2010-07-02 8:34 ` [PATCH 2/4] workqueue: fix race condition in flush_workqueue() Tejun Heo
2010-07-02 8:35 ` [PATCH 3/4] workqueue: fix incorrect cpu number BUG_ON() in get_work_gcwq() Tejun Heo
2010-07-02 8:35 ` [PATCH 4/4] workqueue: fix worker management invocation without pending works Tejun Heo
2010-07-19 14:51 ` [PATCHSET] workqueue: concurrency managed workqueue, take#6 Tejun Heo
2010-07-21 13:23 ` David Howells
2010-07-21 14:52 ` Tejun Heo
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