linux-kernel - Re: [PATCH v5]: Improve performance of LZO hibernation

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Date:	Thu, 29 Sep 2011 18:23:32 +1000
From:	Bojan Smojver <bojan@...ursive.com>
To:	Pekka Enberg <penberg@...helsinki.fi>
Cc:	linux-kernel@...r.kernel.org, "Rafael J. Wysocki" <rjw@...k.pl>
Subject: Re: [PATCH v5]: Improve performance of LZO hibernation

On Wed, 2011-09-28 at 16:02 +0300, Pekka Enberg wrote:
> On Wed, Sep 28, 2011 at 10:54 AM, Bojan Smojver <bojan@...ursive.com> wrote:
> > I'm guessing here that you mean that parts of the kernel other than
> > hibernation code itself can do this (i.e. set the flag for the thread to
> > stop, so kthread_should_stop() returns true). Correct?
> 
> Sorry, I'm not familiar this code. However, if you're checking for the
> condition..
> 
> [snip]
> 
> > Right now, this would result in - well I don't know what exactly - most
> > likely corrupted data on disk or on memory.
> 
> ...this is not really an option for handling it.

I think we should be good with v7. If anyone called kthread_stop(),
error codes will be set. And we discard hibernation/thaw attempt based
on errors coming from compression/decompression threads.

In terms of thread pointer becoming a dangling one, I don't think that's
a worry. I see many instances of kthread_stop() throughout the kernel
code and none of them worry themselves with the pointer being bad.

I may still have v8, with some variable name cleanups and some redundant
code taken out.

-- 
Bojan

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