Re: [PATCH 2/6] mm: mark all calls into the vmalloc subsystem as potentially sleeping

From: Christoph Hellwig
Date: Tue Oct 18 2016 - 06:39:12 EST

On Tue, Oct 18, 2016 at 11:33:59AM +0100, Chris Wilson wrote:
> On Tue, Oct 18, 2016 at 08:56:07AM +0200, Christoph Hellwig wrote:
> > This is how everyone seems to already use them, but let's make that
> > explicit.
> mm/page_alloc.c: alloc_large_system_hash() is perhaps the exception to
> the rule.

While alloc_large_system_hash passes GFP_ATOMIC it still is called
from context where it can sleep - I think it just abuses GFP_ATOMIC
so that it gets an "early" failure. For which GFP_ATOMIC isn't
exactly a good choice as it dips into additional reserves, GFP_NOWAIT
would have probably been a better choice.