Re: [patch -mmotm] mm: invoke oom killer for __GFP_NOFAIL

From: David Rientjes
Date: Mon May 11 2009 - 04:41:16 EST


On Mon, 11 May 2009, Minchan Kim wrote:

> Hmm.. if __alloc_pages_may_oom fail to allocate free page due to order > PAGE_ALLOC_COSTRY_ORDER,
>
> It will go to nopage label in __alloc_pages_slowpath.
> Then it will show the page allocation failure warning and will return.
> Retrying depends on caller.
>

Correct.

> So, I think it won't loop forever.
> Do I miss something ?
>

__GFP_NOFAIL allocations shouldn't fail, that's the point of the gfp flag.
So failing without attempting to free some memory is the wrong thing to
do.

> In addition, the OOM killer can help for getting the high order pages ?
>

Sure, if it selects a task that will free a lot of memory, which is it's
goal.
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