From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mel Gorman Subject: Re: [PATCH 0/5] Improve sequential read throughput v4r8 Date: Tue, 1 Jul 2014 21:58:17 +0100 Message-ID: <20140701205817.GY10819@suse.de> References: <1404146883-21414-1-git-send-email-mgorman@suse.de> <20140701171611.GB1369@cmpxchg.org> <20140701183915.GW10819@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Cc: Andrew Morton , Linux Kernel , Linux-MM , Linux-FSDevel To: Johannes Weiner Return-path: Content-Disposition: inline In-Reply-To: <20140701183915.GW10819@suse.de> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Tue, Jul 01, 2014 at 07:39:15PM +0100, Mel Gorman wrote: > The fair zone policy itself is partially working against the lowmem > reserve idea. The point of the lowmem reserve was to preserve the lower > zones when an upper zone can be used and the fair zone policy breaks > that. The fair zone policy ignores that and it was never reconciled. The > dirty page distribution does a different interleaving again and was never > reconciled with the fair zone policy or lowmem reserves. kswapd itself was > not using the classzone_idx it actually woken for although in this case > it may not matter. The end result is that the model is fairly inconsistent > which makes comparison against it a difficult exercise at best. About all > that was left was that from a performance perspective that the fair zone > allocation policy is not doing the right thing for streaming workloads. > The inevitable feedback will be to reconcile those differences so I'm redid the series and queued it for testing. Patch list currently looks like mm: pagemap: Avoid unnecessary overhead when tracepoints are deactivated mm: Rearrange zone fields into read-only, page alloc, statistics and page reclaim lines mm: page_alloc: Add ALLOC_DIRTY for dirty page distribution mm: page_alloc: Only apply the fair zone allocation policy if it's eligible mm: page_alloc: Only apply either the fair zone or dirty page distribution policy, not both mm: page_alloc: Reduce cost of the fair zone allocation policy mm: page_alloc: Reconcile lowmem reserves with fair zone allocation policy mm: vmscan: Fix oddities with classzone and zone balancing mm: vmscan: Reconcile balance gap lowmem reclaim with fair zone allocation policy mm: vmscan: Remove classzone considerations from kswapd decisions About 13 hours to test for ext3 on the small machine, 3 days for the larger machine. The test could be accelerated by either reducing the iterations or the memory size of the machine but that would distort the results too badly. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org