From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail07.adl2.internode.on.net (ipmail07.adl2.internode.on.net [150.101.137.131]) by lists.ozlabs.org (Postfix) with ESMTP id 2688D1A00B0 for ; Fri, 20 Mar 2015 11:23:26 +1100 (AEDT) Date: Fri, 20 Mar 2015 11:23:11 +1100 From: Dave Chinner To: Linus Torvalds Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur Message-ID: <20150320002311.GG28621@dastard> References: <20150317070655.GB10105@dastard> <20150317205104.GA28621@dastard> <20150317220840.GC28621@dastard> <20150319224143.GI10105@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Cc: Linux Kernel Mailing List , xfs@oss.sgi.com, Linux-MM , Aneesh Kumar , Andrew Morton , ppc-dev , Ingo Molnar , Mel Gorman List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Mar 19, 2015 at 04:05:46PM -0700, Linus Torvalds wrote: > Can you try Mel's change to make it use > > if (!(vma->vm_flags & VM_WRITE)) > > instead of the pte details? Again, on otherwise plain 3.19, just so > that we have a baseline. I'd be *so* much happer with checking the vma > details over per-pte details, especially ones that change over the > lifetime of the pte entry, and the NUMA code explicitly mucks with. $ sudo perf_3.18 stat -a -r 6 -e migrate:mm_migrate_pages sleep 10 Performance counter stats for 'system wide' (6 runs): 266,750 migrate:mm_migrate_pages ( +- 7.43% ) 10.002032292 seconds time elapsed ( +- 0.00% ) Bit more variance there than the pte checking, but runtime difference is in the noise - 5m4s vs 4m54s - and profiles are identical to the pte checking version. Cheers, Dave. -- Dave Chinner david@fromorbit.com