Re: [PATCH] vmscan: don't use return value trick when oom_killer_disabled

From: KOSAKI Motohiro
Date: Fri Sep 03 2010 - 02:33:16 EST


> 2010/9/3 Rafael J. Wysocki <rjw@xxxxxxx>:
> > On Thursday, September 02, 2010, Minchan Kim wrote:
> >> M. Vefa Bicakci reported 2.6.35 kernel hang up when hibernation on his
> >> 32bit 3GB mem machine. (https://bugzilla.kernel.org/show_bug.cgi?id=16771)
> >> Also he was bisected first bad commit is below
> >>
> >>   commit bb21c7ce18eff8e6e7877ca1d06c6db719376e3c
> >>   Author: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> >>   Date:   Fri Jun 4 14:15:05 2010 -0700
> >>
> >>      vmscan: fix do_try_to_free_pages() return value when priority==0 reclaim failure
> >>
> >> At first impression, this seemed very strange because the above commit only
> >> chenged function return value and hibernate_preallocate_memory() ignore
> >> return value of shrink_all_memory(). But it's related.
> >>
> >> Now, page allocation from hibernation code may enter infinite loop if
> >> the system has highmem.
> >>
> >> The reasons are two. 1) hibernate_preallocate_memory() call
> >> alloc_pages() wrong order
> >
> > This isn't the case, as explained here: http://lkml.org/lkml/2010/9/1/316 .
> >
> > The ordering of calls is correct, but it's better to check if there are any
> > non-highmem pages to allocate from before the last call (for performance
> > reasons, but that also would eliminate the failure in question).
>
> I actually didn't look into the 1) problem detail.
> Just copy and paste from KOSAKI's description.
> As I look the thread, KOSAKI seem to admit the description is wrong.
> I will resend the patch removing phrase about 1) problem if KOSAKI don't mind.
> KOSAKI. Is it okay?

Yeah! please :)




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