[stable] PM / Hibernate: Hibernate/thaw fixes/improvements

[Ben Hutchings]

On Wed, 2012-07-11 at 16:08 -0500, Manoj Iyer wrote:
> Please consider the following upstream patch to stable 3.2.y linux-stable
>
> Patch:  PM / Hibernate: Hibernate/thaw fixes/improvements
> 
> commit 5a21d489fd9541a4a66b9a500659abaca1b19a51
> Author: Bojan Smojver <bojan at rexursive.com>
> Date:   Sun Apr 29 22:42:06 2012 +0200
> 
>      PM / Hibernate: Hibernate/thaw fixes/improvements
> 
>       1. Do not allocate memory for buffers from emergency pools, unless
>          absolutely required. Do not warn about and do not retry non-essential
>          failed allocations.
> 
>       2. Do not check the amount of free pages left on every single page
>          write, but wait until one map is completely populated and then check.
> 
>       3. Set maximum number of pages for read buffering consistently, instead
>          of inadvertently depending on the size of the sector type.
> 
>       4. Fix copyright line, which I missed when I submitted the hibernation
>          threading patch.
> 
>       5. Dispense with bit shifting arithmetic to improve readability.
> 
>       6. Really recalculate the number of pages required to be free after all
>          allocations have been done.
> 
>       7. Fix calculation of pages required for read buffering. Only count in
>          pages that do not belong to high memory.
> 
>      Signed-off-by: Bojan Smojver <bojan at rexursive.com>
>      Signed-off-by: Rafael J. Wysocki <rjw at sisk.pl>

I don't know about this.  It sounds like it's making a lot of different
changes, not all of which are that important.  But perhaps this is just
a verbose description of a single logical change (it's certainly not a
very large change).

> This patch fixes S4 issues on Lenovo and thinkpad models. The patch applies
> cleanly to:
> git://git.kernel.org/pub/scm/linux/kernel/git/bwh/linux-3.2.y.git
> tree. and the patch was tested on Ubuntu precise by me on Lenovo system.
[...]

I wonder why it would fix these specific systems, as there's nothing
obviously hardware-specific there.  Or, it fixes those, whether it might
at the same time cause regressions for other systems.

Bojan, can you comment on whether you think this meets the stable update
criteria?

Ben.

-- 
Ben Hutchings
The generation of random numbers is too important to be left to chance.
                                                            - Robert Coveyou
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