linux-kernel - Re: [PATCH 4/7] sched: implement force_cpus

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: <1260268739.3935.1113.camel@laptop>
Date:	Tue, 08 Dec 2009 11:38:59 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Tejun Heo <tj@...nel.org>
Cc:	tglx@...utronix.de, mingo@...e.hu, avi@...hat.com, efault@....de,
	rusty@...tcorp.com.au, linux-kernel@...r.kernel.org,
	Gautham R Shenoy <ego@...ibm.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 4/7] sched: implement force_cpus_allowed()

On Tue, 2009-12-08 at 11:34 +0100, Peter Zijlstra wrote:
> On Tue, 2009-12-08 at 18:12 +0900, Tejun Heo wrote:
> > > So its only needed in order to flush a workqueue from CPU_DOWN_PREPARE?
> > > And all you need it to place a new kthread on a !active cpu?
> > 
> > Yes, that's all I need. 
> 
> Then you don't need most of that patch, you don't need to touch the
> migration stuff since a new kthread isn't running.
> 
> All you need to do is make a kthread_bind/set_cpus_allowed variant that
> checks against cpu_online_mask instead of cpu_active_mask.
> 
> It might even make sense to have kthread_bind() always check with
> cpu_online_mask as the kernel really ought to know what its doing
> anyway.
> 
> You also don't need to play trickery with PF_THREAD_BOUND, since a new
> kthread will not have that set.
> 
> In fact, your patch is against a tree that still has cpu_online_mask in
> all those places, so you wouldn't have needed any of that, confused.. ?!

More confusion, kthread_bind() doesn't even use set_cpus_allowed() so it
wouldn't have hit any of that crap.

--
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/