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From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Tejun Heo <tj@kernel.org>
Cc: rjw@sisk.pl, pavel@ucw.cz, len.brown@intel.com,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] PM/Freezer: Make thaw_processes() thaw only userspace tasks
Date: Tue, 31 Jan 2012 03:53:05 +0530	[thread overview]
Message-ID: <4F271849.302@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120130220919.GC27616@google.com>

On 01/31/2012 03:39 AM, Tejun Heo wrote:

> On Tue, Jan 31, 2012 at 03:34:57AM +0530, Srivatsa S. Bhat wrote:
>> Currently the situation is:
>>
>> freeze_processes() - freezes only userspace tasks
>> freeze_kernel_threads() - freezes only kernel threads
>> thaw_kernel_threads() - thaws only kernel threads
>> thaw_processes() - thaws *everything* (both userspace tasks and kernel threads)
>>
>> The point that thaw_processes() thaws everything is rather unintuitive
>> and can lead to bugs. So, modify thaw_processes() so that it thaws only
>> userspace processes. This way we can also have more control over what
>> exactly gets thawed in different situations.
>>
>> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
> 
> Maybe I'm misreading it but doesn't this introduce window where kernel
> tasks aren't thawed between this patch and the following ones?  It
> looks like this one should come later.
> 


Yes, I was aware that it introduces such a window. But I ignored it in the
interest of making the patch series sensible (as in, for example, patch
2/4 wouldn't make much sense without patch 1/4).
Maybe I will interchange patch 1 and patch 2 and just reword the patch
descriptions suitably so that they still make sense..

Thanks a lot!

Regards,
Srivatsa S. Bhat


  reply	other threads:[~2012-01-30 22:23 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-30 22:04 [PATCH 0/4] PM / Freezer: Fix the semantics of thaw_processes() and thaw_kernel_threads() Srivatsa S. Bhat
2012-01-30 22:04 ` [PATCH 1/4] PM/Freezer: Make thaw_processes() thaw only userspace tasks Srivatsa S. Bhat
2012-01-30 22:09   ` Tejun Heo
2012-01-30 22:23     ` Srivatsa S. Bhat [this message]
2012-01-30 22:27       ` Tejun Heo
2012-01-30 22:05 ` [PATCH 2/4] PM/Freezer: Use thaw_processes() and thaw_kernel_threads() correctly Srivatsa S. Bhat
2012-01-30 22:05 ` [PATCH 3/4] PM/Hibernate: Thaw kernel threads in hibernation_snapshot() in error/test path Srivatsa S. Bhat
2012-01-30 22:05 ` [PATCH 4/4] PM/Hibernate: Refactor and simplify freezer_test_done Srivatsa S. Bhat

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