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From: Pavel Machek <pavel@suse.cz>
To: Christoph Lameter <christoph@lameter.com>
Cc: akpm@osdl.org, torvalds@osdl.org, linux-kernel@vger.kernel.org
Subject: Re: Alternative to TIF_FREEZE -> a notifier in the task_struct?
Date: Thu, 28 Jul 2005 09:41:16 +0200	[thread overview]
Message-ID: <20050728074116.GF6529@elf.ucw.cz> (raw)
In-Reply-To: <Pine.LNX.4.62.0507272018060.11863@graphe.net>

Hi!

> This could be used to have a process execute any other piece that is 
> required to run in the context of the thread. Maybe such a feature could 
> help with PTRACE or/and get_user_pages that currently do ugly things to a 
> process. It may also allow changing values that so far cannot be
> changed from the outside in the task struct by running a function
> in the context of the process.

Well, we really need slightly more from "running in process context":
we also need "no locks held" for swsusp. (But other uses probably do,
too?)

> Here is a patch against Linus current tree that does this. Note that this 
> patch is incomplete at this point and only a basis for further discussion. 
> Not all software suspend checkpoints are useful for a notifier chain. We 
> would need to inspect several cases where drivers/kernel threads have 
> special functionality for software suspend.

I guess I'd prefer if you left "refrigerator()" and "try_to_freeze()"
functions in; there are about 1000 drivers that know/use them, and
some patches are probably in the queue....

								Pavel
-- 
teflon -- maybe it is a trademark, but it should not be.

  reply	other threads:[~2005-07-28  7:41 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <200507260340.j6Q3eoGh029135@shell0.pdx.osdl.net>
2005-07-28  3:30 ` Alternative to TIF_FREEZE -> a notifier in the task_struct? Christoph Lameter
2005-07-28  7:41   ` Pavel Machek [this message]
2005-07-28 15:05     ` Christoph Lameter
2005-07-28 19:34       ` Pavel Machek
2005-07-28 19:49         ` Christoph Lameter
2005-07-28 19:54         ` [PATCH 1/4] Task notifier: Allow the removal of a notifier from the notifier handler Christoph Lameter
2005-07-28 19:55           ` [PATCH 2/4] Task notifier: Implement todo list in task_struct Christoph Lameter
2005-07-28 19:57             ` [PATCH 3/4] Task notifier: Make suspend code SMP safe using the todo list in the task struct Christoph Lameter
2005-07-28 19:59               ` [PATCH 4/4] Task notifier: s/try_to_freeze/try_todo_list/ in some drivers [optional] Christoph Lameter
2005-07-28 21:27             ` [PATCH 2/4] Task notifier: Implement todo list in task_struct Pavel Machek
2005-07-28 21:32               ` Pavel Machek
2005-07-28 21:57                 ` Christoph Lameter
2005-07-28 22:12                   ` Pavel Machek
2005-07-28 23:02                     ` Christoph Lameter
2005-07-28 23:27                       ` Andrew Morton
2005-07-29  0:19                         ` Christoph Lameter
2005-08-09  1:32                   ` Nigel Cunningham
2005-08-09  2:01                     ` Christoph Lameter
2005-08-09  3:51                       ` Nigel Cunningham
2005-08-09  4:21                         ` Nigel Cunningham
2005-08-09 17:05                         ` Christoph Lameter

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