From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>,
Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@osdl.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
LHCS list <lhcs-devel@lists.sourceforge.net>
Subject: Re: [Experimental CPU Hotplug PATCH] - Move migrate_all_tasks to CPU_DEAD handling
Date: Wed, 7 Apr 2004 19:47:21 +0530 [thread overview]
Message-ID: <20040407141721.GA12876@in.ibm.com> (raw)
In-Reply-To: <1081315931.5922.151.camel@bach>
On Wed, Apr 07, 2004 at 03:32:12PM +1000, Rusty Russell wrote:
> But other tasks can do a getaffinity() on it and see the wrong affinity.
> Probably not a big issue.
hmm .. the fact that getaffinity reads the cpus_allowed mask w/o doing
lock_cpu_hotplug makes it already racy wrt setaffinity?
Maybe it needs to take CPU hotplug sem before it reads the mask?
> I agree with Ingo: it's clever, well done. Minor nitpicks:
>
> +void migrate_all_tasks(int cpu)
> {
> struct task_struct *tsk, *t;
> int dest_cpu, src_cpu;
> unsigned int node;
>
> - /* We're nailed to this CPU. */
> - src_cpu = smp_processor_id();
> + src_cpu = cpu;
>
> Just make the parameter name "src_cpu"?
[snip]
> This comment's very big. They don't need to know all the things we
> don't do. I'd prefer:
>
> /* Force idle task to run as soon as we yield: it should
> immediately notice cpu is offline and die quickly. */
Sure, I will change as per your comments.
I would like to run my stress tests for longer time before I send it
for inclusion (i would be on vacation till next tuesday ..so maybe i will send
in the patch after that!)
--
Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017
next prev parent reply other threads:[~2004-04-07 14:16 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-05 12:18 [Experimental CPU Hotplug PATCH] - Move migrate_all_tasks to CPU_DEAD handling Srivatsa Vaddagiri
2004-04-06 0:28 ` Nick Piggin
2004-04-06 1:15 ` Srivatsa Vaddagiri
2004-04-06 1:27 ` Nick Piggin
2004-04-06 1:30 ` Nick Piggin
2004-04-06 16:43 ` [lhcs-devel] " Srivatsa Vaddagiri
2004-04-06 8:37 ` Srivatsa Vaddagiri
2004-04-06 9:26 ` Nick Piggin
2004-04-06 14:56 ` Srivatsa Vaddagiri
2004-04-06 15:04 ` Nick Piggin
2004-04-06 15:20 ` Srivatsa Vaddagiri
2004-04-07 3:54 ` Rusty Russell
2004-04-07 4:11 ` Nick Piggin
2004-04-07 5:01 ` Srivatsa Vaddagiri
2004-04-07 5:32 ` Rusty Russell
2004-04-07 14:17 ` Srivatsa Vaddagiri [this message]
2004-04-07 22:55 ` Rusty Russell
2004-04-12 16:08 ` [lhcs-devel] " Srivatsa Vaddagiri
2004-04-06 7:25 ` Ingo Molnar
2004-04-06 14:53 ` Srivatsa Vaddagiri
2004-04-06 15:03 ` Srivatsa Vaddagiri
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