[Bisected Regression in 2.6.35] A full tmpfs filesystem causes hibernationto hang

["M. Vefa Bicakci" <bicave@superonline.com>]

Hello all,

I am using Debian Sid on a Toshiba Satellite A100 laptop. After testing
2.6.35 for a while, I noticed that sometimes my hibernation attempts
would fail. I should say that I never had such a problem before 2.6.35.
The hibernation process hangs with 2.6.35 after printing the following:

=== 8< ===
...
Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done.
PM: Preallocating image memory...
=== >8 ===

After a short investigation, I found out that this only happens when my
tmpfs filesystem on /tmp had a lot of data in it. When my tmpfs is empty,
I have no problems.

So I wrote a short script which fills up the tmpfs on /tmp and tries to
hibernate, and I bisected the kernel using this script.

The end result is that the following commit causes this regression:

=== 8< ===
commit bb21c7ce18eff8e6e7877ca1d06c6db719376e3c
Author: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date:   Fri Jun 4 14:15:05 2010 -0700

    vmscan: fix do_try_to_free_pages() return value when priority==0 reclaim failure

    ...
=== >8 ===

I have run 2.6.35-rc6, 2.6.35 and 2.6.35.1 with this commit reverted,
and I am happy to say that I haven't experienced any problems for at
least 17 days.

It looks like this change was included with 2.6.35-rc1. I am sorry
for not testing earlier.

I am willing to do testing in case anyone would like me to try patches.

Regards,

M. Vefa Bicakci