Re: [RFC][PATCH] PM: Force GFP_NOIO during suspend/resume (was: Re: [linux-pm] Memory allocations in .suspend became very unreliable)

Rafael J. Wysocki
2010-01-20T21:12:40Z

On Wednesday 20 January 2010, Oliver Neukum wrote:
> Am Dienstag, 19. Januar 2010 21:37:35 schrieb Rafael J. Wysocki:
> > That said, Maxim reported that in his test case the mm subsystem apparently
> > attempted to use I/O even if there was a plenty of free memory available and
> > I'd like prevent that from happening.
>
> Hi,
>
> it seems to me that this is caused by the mm subsytem maintaing
> a share of clean pages precisely so that GFP_NOIO will work.
> Perhaps it is a good idea to
> a) launder a number of pages if the system is about to be suspended
> between the freezer and notifying drivers

That was tried, didn't work.

> b) set the ration of clean pages to dirty pages to 0 while suspending
> the system.

Patch, please?

Rafael