Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag

From: David Rientjes
Date: Thu May 07 2009 - 16:43:00 EST


On Thu, 7 May 2009, Rafael J. Wysocki wrote:

> > Third time I'm going to suggest this, and I'd like a response on why it's
> > not possible instead of being ignored.
> >
> > All of your tasks are in D state other than kthreads, right? That means
> > they won't be in the oom killer (thus no zones are oom locked), so you can
> > easily do this
> >
> > struct zone *z;
> > for_each_populated_zone(z)
> > zone_set_flag(z, ZONE_OOM_LOCKED);
> >
> > and then
> >
> > for_each_populated_zone(z)
> > zone_clear_flag(z, ZONE_OOM_LOCKED);
> >
> > The serialization is done with trylocks so this will never invoke the oom
> > killer because all zones in the allocator's zonelist will be oom locked.
> >
> > Why does this not work for you?
>
> Well, it might work too, but why are you insisting? How's it better than
> __GFP_NO_OOM_KILL, actually?
>

Because I agree with Christoph's concerns about needlessly adding
additional gfp flags; he was responding to the proposed addition of
__GFP_PANIC which could be handled in other much simpler ways just like
this flag can as I've shown.
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