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

Rafael J. Wysocki
2010-01-17T13:35:53Z

On Sunday 17 January 2010, Rafael J. Wysocki wrote:
> On Sunday 17 January 2010, Oliver Neukum wrote:
> > Am Sonntag, 17. Januar 2010 01:38:37 schrieb Rafael J. Wysocki:
> > > > Now having said that, we've been considering a change that will turn all
> > > > GFP_KERNEL allocations into GFP_NOIO during suspend/resume, so perhaps I'll
> > > > prepare a patch to do that and let's see what people think.
> > >
> > > If I didn't confuse anything (which is likely, because it's a bit late here
> > > now), the patch below should do the trick. I have only checked that it doesn't
> > > break compilation, so please take it with a grain of salt.
> > >
> > > Comments welcome.
> >
> > I think this is a bad idea as it makes the mm subsystem behave differently
> > in the runtime and in the whole system cases.
>
> s/runtime/suspend/ ?
>
> Yes it will, but why exactly shouldn't it? System suspend/resume _is_ a
> special situation anyway.

Moreover, as the Maxim's report indicates, the mm subsystem already behaves
differently during suspend/resume and this behavior is erroneous, because it
causes the system to hang.

Rafael