Re: [PATCH 05/10] mm, page_alloc: Distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd

From: Mel Gorman
Date: Fri Sep 25 2015 - 08:51:14 EST


On Thu, Sep 24, 2015 at 04:55:09PM -0400, Johannes Weiner wrote:
> On Mon, Sep 21, 2015 at 11:52:37AM +0100, Mel Gorman wrote:
> > @@ -119,10 +134,10 @@ struct vm_area_struct;
> > #define GFP_USER (__GFP_WAIT | __GFP_IO | __GFP_FS | __GFP_HARDWALL)
> > #define GFP_HIGHUSER (GFP_USER | __GFP_HIGHMEM)
> > #define GFP_HIGHUSER_MOVABLE (GFP_HIGHUSER | __GFP_MOVABLE)
> > -#define GFP_IOFS (__GFP_IO | __GFP_FS)
> > -#define GFP_TRANSHUGE (GFP_HIGHUSER_MOVABLE | __GFP_COMP | \
> > - __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN | \
> > - __GFP_NO_KSWAPD)
> > +#define GFP_IOFS (__GFP_IO | __GFP_FS | __GFP_KSWAPD_RECLAIM)
>
> These are some really odd semantics to be given a name like that.
>
> GFP_IOFS was introduced as a short-hand for testing/setting/clearing
> these two bits at the same time, not to be used for allocations. In
> fact, the only user for allocations is lustre, and it's not at all
> obious why those sites shouldn't include __GFP_WAIT as well.
>
> Removing this definition altogether would probably be best.

Ok, I'll add a TODO to create a patch that removes GFP_IOFS entirely. It
can be tacked on to the end of the series.

--
Mel Gorman
SUSE Labs
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