linux-kernel - Re: [PATCH 3/4] workqueue: Create low-level unbound workqueues cpumask

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <7hy4n0o0xt.fsf@deeprootsystems.com>
Date:	Fri, 13 Mar 2015 17:52:14 -0700
From:	Kevin Hilman <khilman@...prootsystems.com>
To:	Lai Jiangshan <laijs@...fujitsu.com>
Cc:	<linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Christoph Lameter <cl@...ux.com>,
	Mike Galbraith <bitbucket@...ine.de>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Tejun Heo <tj@...nel.org>,
	Viresh Kumar <viresh.kumar@...aro.org>
Subject: Re: [PATCH 3/4] workqueue: Create low-level unbound workqueues cpumask

Kevin Hilman <khilman@...nel.org> writes:

> Lai Jiangshan <laijs@...fujitsu.com> writes:
>
>> From: Frederic Weisbecker <fweisbec@...il.com>
>>
>> Create a cpumask that limit the affinity of all unbound workqueues.
>> This cpumask is controlled though a file at the root of the workqueue
>> sysfs directory.
>>
>> It works on a lower-level than the per WQ_SYSFS workqueues cpumask files
>> such that the effective cpumask applied for a given unbound workqueue is
>> the intersection of /sys/devices/virtual/workqueue/$WORKQUEUE/cpumask and
>> the new /sys/devices/virtual/workqueue/cpumask_unbounds file.
>>
>> This patch implements the basic infrastructure and the read interface.
>> cpumask_unbounds is initially set to cpu_possible_mask.
>>
>> Cc: Christoph Lameter <cl@...ux.com>
>> Cc: Kevin Hilman <khilman@...aro.org>
>> Cc: Lai Jiangshan <laijs@...fujitsu.com>
>> Cc: Mike Galbraith <bitbucket@...ine.de>
>> Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
>> Cc: Tejun Heo <tj@...nel.org>
>> Cc: Viresh Kumar <viresh.kumar@...aro.org>
>> Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
>> Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com>
>
> [...]
>
>> @@ -5094,6 +5116,9 @@ static int __init init_workqueues(void)
>>  
>>  	WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
>>  
>> +	BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
>> +	cpumask_copy(wq_unbound_cpumask, cpu_possible_mask);
>> +
>
> As I mentioned in an earlier discussion[1], I still think this could
> default too the housekeeping CPUs in the NO_HZ_FULL case:
>
> #ifdef CONFIG_NO_HZ_FULL
> 	cpumask_complement(wq_unbound_cpumask, tick_nohz_full_mask);
> #else
> 	cpumask_copy(wq_unbound_cpumask, cpu_possible_mask);
> #endif
>
> But that could also be left to a future optimization as well.

I meant to add:

Acked-by: Kevin Hilman <khilman@...aro.org>

as well, as the NO_HZ_FULL bit could be added as an add-on patch.

Kevin
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/