From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>, Bjorn Helgaas <bjorn.helgaas@hp.com>,
linux-kernel@vger.kernel.org, Myron Stowe <myron.stowe@hp.com>,
Jens Axboe <axboe@kernel.dk>, Dipankar <dipankar@in.ibm.com>,
Gautham shenoy <ego@in.ibm.com>
Subject: Re: workqueue deadlock
Date: Mon, 11 Dec 2006 11:15:45 +0530 [thread overview]
Message-ID: <20061211054545.GC5339@in.ibm.com> (raw)
In-Reply-To: <20061210041600.56306676.akpm@osdl.org>
On Sun, Dec 10, 2006 at 04:16:00AM -0800, Andrew Morton wrote:
> One quite different way of addressing all of this is to stop using
> stop_machine_run() for hotplug synchronisation and switch to the swsusp
> freezer infrastructure: all kernel threads and user processes need to stop
> and park themselves in a known state before we allow the CPU to be removed.
> lock_cpu_hotplug() becomes a no-op.
Well ...you still need to provide some mechanism for stable access to
cpu_online_map in blocking functions (ex: do_event_scan_all_cpus).
Freezing-tasks/Resuming-them-after-hotp-unplug is definitely not one of them
(when they resume, online_map would have changed under their feet).
> Dunno if it'll work - I only just thought of it. It sure would simplify
> things.
--
Regards,
vatsa
next prev parent reply other threads:[~2006-12-11 5:46 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-07 0:26 workqueue deadlock Bjorn Helgaas
2006-12-07 6:17 ` Srivatsa Vaddagiri
2006-12-07 6:45 ` Srivatsa Vaddagiri
2006-12-07 18:51 ` Andrew Morton
2006-12-07 19:37 ` Andrew Morton
2006-12-08 2:53 ` Srivatsa Vaddagiri
2006-12-08 4:54 ` Andrew Morton
2006-12-08 7:58 ` Srivatsa Vaddagiri
2006-12-09 10:26 ` Ingo Molnar
2006-12-09 19:47 ` Andrew Morton
2006-12-10 8:26 ` Ingo Molnar
2006-12-10 8:43 ` Andrew Morton
2006-12-10 11:49 ` Ingo Molnar
2006-12-10 12:16 ` Andrew Morton
2006-12-10 12:19 ` Ingo Molnar
2006-12-10 12:34 ` Andrew Morton
2006-12-11 6:09 ` Ingo Molnar
2006-12-10 14:18 ` Rafael J. Wysocki
2006-12-11 6:52 ` Dipankar Sarma
2006-12-11 16:34 ` Rafael J. Wysocki
2006-12-11 5:45 ` Srivatsa Vaddagiri [this message]
2006-12-11 6:03 ` Andrew Morton
2006-12-11 4:58 ` Srivatsa Vaddagiri
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