linux-kernel - Re: [PATCHSET wq/for-3.10] workqueue: NUMA affinity for unbound workqueues

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]

Date:	Sun, 24 Mar 2013 11:55:06 -0700
From:	Tejun Heo <tj@...nel.org>
To:	Lai Jiangshan <eag0628@...il.com>
Cc:	laijs@...fujitsu.com, axboe@...nel.dk, jack@...e.cz,
	fengguang.wu@...el.com, jmoyer@...hat.com, zab@...hat.com,
	linux-kernel@...r.kernel.org, herbert@...dor.apana.org.au,
	davem@...emloft.net, linux-crypto@...r.kernel.org
Subject: Re: [PATCHSET wq/for-3.10] workqueue: NUMA affinity for unbound
 workqueues

Hey, Lai.

On Mon, Mar 25, 2013 at 12:04:19AM +0800, Lai Jiangshan wrote:
> example:
> node0(cpu0,cpu1),node1(cpu2,cpu3),
> wq's cpumask: 1,3
> the pwq of this wq on the node1's cpumask: 3
> current online cpu: 0-2.
> so the cpumask of worker tasks of the pwq on node1 is actually cpu_all_mask.
> so the work scheduled from cpu2 can be executed on cpu0 or cpu2.
> we expect it is executed on cpu1 only.

Ah, right.  I was hoping to avoid doing pwq swaps on CPU hot[un]plugs
doing everything on possible mask.  Looks like we'll need some
massaging after all.

> It can be fixed by swapping pwqs(node's pwq <-> default pwq)
> when cpuhotplug. But could you reschedule this patchset to wq/for-3.11?

We're still only at -rc4 meaning we still have plenty of time to
resolve whatever issues which come up, so I think I'm still gonna
target 3.10.

> the whole patchset is more complicated than my brain.

It isn't that complex, is it?  I mean, the difficult part - using
multiple pwqs on unbound wq - already happened, and even that wasn't
too complex as it in most part synchronized the behaviors between
per-cpu and unbound workqueues.  All that NUMA support is doing is
mapping different pwqs to different issuing CPUs.

Thanks.

-- 
tejun
--
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/