From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Christoph Lameter <cl@linux.com>
Cc: <linux-kernel@vger.kernel.org>, Kevin Hilman <khilman@linaro.org>,
Mike Galbraith <bitbucket@online.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Tejun Heo <tj@kernel.org>, Viresh Kumar <viresh.kumar@linaro.org>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH 4/4] workqueue: Allow modifying low level unbound workqueue cpumask
Date: Fri, 13 Mar 2015 09:38:27 +0800 [thread overview]
Message-ID: <55023F93.9000304@cn.fujitsu.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1503121241520.7400@gentwo.org>
On 03/13/2015 01:42 AM, Christoph Lameter wrote:
> On Thu, 12 Mar 2015, Lai Jiangshan wrote:
>
>> The per-nodes' pwqs are mandatorily controlled by the low level cpumask, while
>> the default pwq ignores the low level cpumask when (and ONLY when) the cpumask set
>> by the user doesn't overlap with the low level cpumask. In this case, we can't
>> apply the empty cpumask to the default pwq, so we use the user-set cpumask
>> directly.
>
> I am wondering now why we have two cpumasks?
What's your meaning? which two cpumask?
The per-nodes' pwqs' cpumask and the default pwq's cpumask?
They refer to different pool, so they have different cpumask.
1)
If the per-nodes' pwqs exist, they were controlled by A
(A = user-set-cpumask & possible-cpus-of-the-node). Now after this patch,
they are controlled by B (B = A & the-low-level-cpumak).
if A is empty or B is empty, we used default pwq for the node.
2)
The default pwq is different, it was controlled by C (C = user-set-cpumask),
and after this patch, it will be controlled by D
(D = user-set-cpumask(C) & the-low-level-cpumask), But D may be empty,
we can't have a default pwq with empty cpumask, so we have
use C instead in this case.
> A script can just interate
> through the work queues if we want to set them all right? Then we do not
> have to deal with the conflict between the settings in the kernel.
wq->unbound_attrs->cpumask and the-low-level-cpumask can be set by users.
they may be set different or even non-intersect, the non-intersect case
is not real conflict, but it is possible, we have to handle it.
next prev parent reply other threads:[~2015-03-13 1:36 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-12 5:00 [PATCH 0/4] workqueue: Introduce low-level unbound wq sysfs cpumask v4 Lai Jiangshan
2015-03-12 5:00 ` [PATCH 1/4] workqueue: Reorder sysfs code Lai Jiangshan
2015-03-12 5:00 ` [PATCH 2/4] workqueue: split apply_workqueue_attrs() into 3 stages Lai Jiangshan
2015-03-12 5:00 ` [PATCH 3/4] workqueue: Create low-level unbound workqueues cpumask Lai Jiangshan
2015-03-12 17:33 ` Christoph Lameter
2015-03-13 23:49 ` Kevin Hilman
2015-03-14 0:52 ` Kevin Hilman
2015-03-14 7:52 ` Lai Jiangshan
2015-03-16 17:12 ` Kevin Hilman
2015-03-16 17:25 ` Frederic Weisbecker
2015-03-16 19:38 ` Kevin Hilman
2015-03-12 5:00 ` [PATCH 4/4] workqueue: Allow modifying low level unbound workqueue cpumask Lai Jiangshan
2015-03-12 17:42 ` Christoph Lameter
2015-03-13 1:38 ` Lai Jiangshan [this message]
2015-03-13 7:49 ` Lai Jiangshan
2015-03-12 17:49 ` [PATCH 0/4] workqueue: Introduce low-level unbound wq sysfs cpumask v4 Frederic Weisbecker
2015-03-13 6:02 ` Mike Galbraith
2015-03-18 4:40 ` [PATCH 0/4 V5] workqueue: Introduce low-level unbound wq sysfs cpumask v5 Lai Jiangshan
2015-03-18 4:40 ` [PATCH 1/4 V5] workqueue: Reorder sysfs code Lai Jiangshan
2015-03-24 15:41 ` Tejun Heo
2015-03-18 4:40 ` [PATCH 2/4 V5] workqueue: split apply_workqueue_attrs() into 3 stages Lai Jiangshan
2015-03-24 15:55 ` Tejun Heo
2015-03-18 4:40 ` [PATCH 3/4 V5] workqueue: Create low-level unbound workqueues cpumask Lai Jiangshan
2015-03-18 4:40 ` [PATCH 4/4 V5] workqueue: Allow modifying low level unbound workqueue cpumask Lai Jiangshan
2015-03-24 17:31 ` Tejun Heo
2015-03-31 7:46 ` Lai Jiangshan
2015-04-01 8:33 ` Lai Jiangshan
2015-04-01 15:52 ` Tejun Heo
2015-03-19 8:54 ` [PATCH 0/4 V5] workqueue: Introduce low-level unbound wq sysfs cpumask v5 Mike Galbraith
2015-04-02 11:14 ` [PATCH 0/4 V6] " Lai Jiangshan
2015-04-02 11:14 ` [PATCH 1/4 V6] workqueue: Reorder sysfs code Lai Jiangshan
2015-04-06 15:22 ` Tejun Heo
2015-04-02 11:14 ` [PATCH 2/4 V6] workqueue: split apply_workqueue_attrs() into 3 stages Lai Jiangshan
2015-04-06 15:39 ` Tejun Heo
2015-04-02 11:14 ` [PATCH 3/4 V6] workqueue: Create low-level unbound workqueues cpumask Lai Jiangshan
2015-04-02 11:14 ` [PATCH 4/4 V6] workqueue: Allow modifying low level unbound workqueue cpumask Lai Jiangshan
2015-04-06 15:53 ` Tejun Heo
2015-04-07 1:25 ` Lai Jiangshan
2015-04-07 1:58 ` Tejun Heo
2015-04-07 2:33 ` Lai Jiangshan
2015-04-07 11:26 ` [PATCH 1/3 V7] workqueue: split apply_workqueue_attrs() into 3 stages Lai Jiangshan
2015-04-07 11:26 ` [PATCH 2/3 V7] workqueue: Create low-level unbound workqueues cpumask Lai Jiangshan
2015-04-07 11:26 ` [PATCH 3/3 V7] workqueue: Allow modifying low level unbound workqueue cpumask Lai Jiangshan
2015-04-22 19:39 ` Tejun Heo
2015-04-22 23:02 ` Frederic Weisbecker
2015-04-23 6:29 ` Mike Galbraith
2015-04-17 14:57 ` [PATCH 1/3 V7] workqueue: split apply_workqueue_attrs() into 3 stages Tejun Heo
2015-04-20 3:21 ` Lai Jiangshan
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