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Date: Thu, 6 Mar 2014 15:12:06 -0800 From: Andrew Morton <akpm@...ux-foundation.org> To: Johannes Weiner <hannes@...xchg.org> Cc: stable@...nel.org, riel@...hat.com, mgorman@...e.de, jstancek@...hat.com, linux-mm@...ck.org, linux-kernel@...r.kernel.org Subject: Re: [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@...xchg.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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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