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SubjectRe: [merged] mm-page_alloc-reset-aging-cycle-with-gfp_thisnode-v2.patch removed from -mm tree
On Thu, 6 Mar 2014 18:04:04 -0500 Johannes Weiner <hannes@cmpxchg.org> wrote:

> > what bug does it fix and what are the user-visible effects??
>
> Ok, maybe this is better?
>
> ---
>
> GFP_THISNODE is for callers that implement their own clever fallback
> to remote nodes. It restricts the allocation to the specified node
> and does not invoke reclaim, assuming that the caller will take care
> of it when the fallback fails, e.g. through a subsequent allocation
> request without GFP_THISNODE set.
>
> However, many current GFP_THISNODE users only want the node exclusive
> aspect of the flag, without actually implementing their own fallback
> or triggering reclaim if necessary. This results in things like page
> migration failing prematurely even when there is easily reclaimable
> memory available, unless kswapd happens to be running already or a
> concurrent allocation attempt triggers the necessary reclaim.
>
> Convert all callsites that don't implement their own fallback strategy
> to __GFP_THISNODE. This restricts the allocation a single node too,
> but at the same time allows the allocator to enter the slowpath, wake
> kswapd, and invoke direct reclaim if necessary, to make the allocation
> happen when memory is full.

Looks good, thanks. I'll send this Linuswards next week.


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