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

Rafael J. Wysocki
2009-05-07T20:38:13Z

On Thursday 07 May 2009, David Rientjes wrote:
> On Thu, 7 May 2009, Rafael J. Wysocki wrote:
>
> > OK, let's try with __GFP_NO_OOM_KILL first. If there's too much disagreement,
> > I'll use the freezer-based approach instead.
> >
>
> 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?

Andrew, what do you think about this?