From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f180.google.com (mail-ig0-f180.google.com [209.85.213.180]) by kanga.kvack.org (Postfix) with ESMTP id D56DE6B0038 for ; Fri, 20 Mar 2015 13:02:23 -0400 (EDT) Received: by igcau2 with SMTP id au2so24371203igc.0 for ; Fri, 20 Mar 2015 10:02:23 -0700 (PDT) Received: from mail-ie0-x22d.google.com (mail-ie0-x22d.google.com. [2607:f8b0:4001:c03::22d]) by mx.google.com with ESMTPS id d19si5132969icc.71.2015.03.20.10.02.23 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 20 Mar 2015 10:02:23 -0700 (PDT) Received: by ieclw3 with SMTP id lw3so97245939iec.2 for ; Fri, 20 Mar 2015 10:02:23 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20150320041357.GO10105@dastard> References: <20150317205104.GA28621@dastard> <20150317220840.GC28621@dastard> <20150319224143.GI10105@dastard> <20150320002311.GG28621@dastard> <20150320041357.GO10105@dastard> Date: Fri, 20 Mar 2015 10:02:23 -0700 Message-ID: Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur From: Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Dave Chinner Cc: Mel Gorman , Ingo Molnar , Andrew Morton , Aneesh Kumar , Linux Kernel Mailing List , Linux-MM , xfs@oss.sgi.com, ppc-dev On Thu, Mar 19, 2015 at 9:13 PM, Dave Chinner wrote: > > Testing now. It's a bit faster - three runs gave 7m35s, 7m20s and > 7m36s. IOWs's a bit better, but not significantly. page migrations > are pretty much unchanged, too: > > 558,632 migrate:mm_migrate_pages ( +- 6.38% ) Ok. That was kind of the expected thing. I don't really know the NUMA fault rate limiting code, but one thing that strikes me is that if it tries to balance the NUMA faults against the *regular* faults, then maybe just the fact that we end up taking more COW faults after a NUMA fault then means that the NUMA rate limiting code now gets over-eager (because it sees all those extra non-numa faults). Mel, does that sound at all possible? I really have never looked at the magic automatic rate handling.. Linus -- 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