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From: Andrew Morton <akpm@osdl.org>
To: vatsa@in.ibm.com
Cc: Oleg Nesterov <oleg@tv-sign.ru>,
	David Howells <dhowells@redhat.com>,
	Christoph Hellwig <hch@infradead.org>,
	Ingo Molnar <mingo@elte.hu>, Linus Torvalds <torvalds@osdl.org>,
	linux-kernel@vger.kernel.org, Gautham shenoy <ego@in.ibm.com>
Subject: Re: [PATCH] fix-flush_workqueue-vs-cpu_dead-race-update
Date: Sat, 6 Jan 2007 11:11:17 -0800	[thread overview]
Message-ID: <20070106111117.54bb2307.akpm@osdl.org> (raw)
In-Reply-To: <20070106163851.GA13579@in.ibm.com>

On Sat, 6 Jan 2007 22:08:51 +0530
Srivatsa Vaddagiri <vatsa@in.ibm.com> wrote:

> 	This workqueue problem has exposed a classic example of how 
> tough/miserable it can be to write hotplug safe code w/o something like
> lock_cpu_hotplug() ..Are you still inclined towards banning it? :)

I don't ban stuff - I just advocate ;)

I would still prefer that we not try to invent a new magical lock,
but yes, the current approach is looking troublesome.

> FYI, the lock_cpu_hotplug() rewrite proposed by Gautham at
> http://lkml.org/lkml/2006/10/26/65 may still need refinement to avoid
> all the kind of deadlocks we have unearthed with workqueue example. I
> can review that design with Gautham if there is some interest to
> revive lock_cpu_hotplug() ..

Has anyone thought seriously about using the process freezer in the
cpu-down/cpu-up paths?  That way we don't need to lock anything anywhere?

  parent reply	other threads:[~2007-01-06 19:12 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-17 22:34 [PATCH, RFC] reimplement flush_workqueue() Oleg Nesterov
2006-12-18  3:09 ` Linus Torvalds
2006-12-19  0:27 ` Andrew Morton
2006-12-19  0:43   ` Oleg Nesterov
2006-12-19  1:00     ` Andrew Morton
2007-01-04 11:32     ` Srivatsa Vaddagiri
2007-01-04 14:29       ` Oleg Nesterov
2007-01-04 15:56         ` Srivatsa Vaddagiri
2007-01-04 16:31           ` Oleg Nesterov
2007-01-04 16:57             ` Srivatsa Vaddagiri
2007-01-04 17:18         ` Andrew Morton
2007-01-04 18:09           ` Oleg Nesterov
2007-01-04 18:31             ` Andrew Morton
2007-01-05  9:03               ` Srivatsa Vaddagiri
2007-01-05 14:07                 ` Oleg Nesterov
2007-01-06 15:24                   ` Srivatsa Vaddagiri
2007-01-05  8:56           ` Srivatsa Vaddagiri
2007-01-05 12:42             ` Oleg Nesterov
2007-01-06 15:11               ` Srivatsa Vaddagiri
2007-01-06 15:10           ` [PATCH] fix-flush_workqueue-vs-cpu_dead-race-update Oleg Nesterov
2007-01-06 15:45             ` Srivatsa Vaddagiri
2007-01-06 16:30               ` Oleg Nesterov
2007-01-06 16:38                 ` Srivatsa Vaddagiri
2007-01-06 17:34                   ` Oleg Nesterov
2007-01-07 10:43                     ` Srivatsa Vaddagiri
2007-01-07 12:56                       ` Oleg Nesterov
2007-01-07 14:22                         ` Oleg Nesterov
2007-01-07 14:42                           ` Oleg Nesterov
2007-01-07 16:43                           ` Srivatsa Vaddagiri
2007-01-07 17:01                             ` Srivatsa Vaddagiri
2007-01-07 17:33                               ` Oleg Nesterov
2007-01-07 17:18                             ` Oleg Nesterov
2007-01-07 16:21                         ` Srivatsa Vaddagiri
2007-01-07 17:09                           ` Oleg Nesterov
2007-01-06 19:11                   ` Andrew Morton [this message]
2007-01-06 19:13                     ` Ingo Molnar
2007-01-07 11:00                     ` Srivatsa Vaddagiri
2007-01-07 19:59                       ` Andrew Morton
2007-01-07 21:01                         ` [PATCH] flush_cpu_workqueue: don't flush an empty ->worklist Oleg Nesterov
2007-01-08 23:54                           ` Andrew Morton
2007-01-09  5:04                             ` Srivatsa Vaddagiri
2007-01-09  5:26                               ` Andrew Morton
2007-01-09  6:56                                 ` Ingo Molnar
2007-01-09  9:33                                 ` Srivatsa Vaddagiri
2007-01-09  9:44                                   ` Ingo Molnar
2007-01-09  9:51                                   ` Andrew Morton
2007-01-09 10:09                                     ` Srivatsa Vaddagiri
2007-01-09 10:15                                       ` Andrew Morton
2007-01-09 15:07                                 ` Oleg Nesterov
2007-01-09 15:59                                   ` Srivatsa Vaddagiri
2007-01-09 16:38                                     ` Oleg Nesterov
2007-01-09 16:46                                       ` Srivatsa Vaddagiri
2007-01-09 16:56                                         ` Oleg Nesterov
2007-01-14 23:54                                           ` Oleg Nesterov
2007-01-15  4:33                                             ` Srivatsa Vaddagiri
2007-01-15 12:54                                               ` Oleg Nesterov
2007-01-15 13:08                                                 ` Oleg Nesterov
2007-01-15 16:18                                                 ` Srivatsa Vaddagiri
2007-01-15 16:55                                                   ` Oleg Nesterov
2007-01-16  5:26                                                     ` Srivatsa Vaddagiri
2007-01-16 13:27                                                       ` Oleg Nesterov
2007-01-17  6:17                                                         ` Srivatsa Vaddagiri
2007-01-17 15:47                                                           ` Oleg Nesterov
2007-01-17 16:12                                                             ` Srivatsa Vaddagiri
2007-01-17 17:01                                                               ` Oleg Nesterov
2007-01-17 16:25                                                             ` Srivatsa Vaddagiri
2007-01-07 21:51                         ` [PATCH] fix-flush_workqueue-vs-cpu_dead-race-update Oleg Nesterov
2007-01-08 15:22                           ` Srivatsa Vaddagiri
2007-01-08 15:56                             ` Oleg Nesterov
2007-01-08 16:31                               ` Srivatsa Vaddagiri
2007-01-08 17:06                                 ` Oleg Nesterov
2007-01-08 18:37                                   ` Pallipadi, Venkatesh
2007-01-09  1:11                                     ` Srivatsa Vaddagiri
2007-01-09  4:39                                   ` Srivatsa Vaddagiri
2007-01-09 14:38                                     ` Oleg Nesterov
2007-01-08 15:37                         ` Srivatsa Vaddagiri
2007-01-04 12:02 ` [PATCH, RFC] reimplement flush_workqueue() Srivatsa Vaddagiri
2007-01-04 14:38   ` Oleg Nesterov

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