From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760108AbcINJZ5 (ORCPT ); Wed, 14 Sep 2016 05:25:57 -0400 Received: from mx2.suse.de ([195.135.220.15]:56759 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751584AbcINJZz (ORCPT ); Wed, 14 Sep 2016 05:25:55 -0400 Date: Wed, 14 Sep 2016 10:25:51 +0100 From: Mel Gorman To: Rik van Riel Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, peterz@infradead.org, mingo@kernel.org, aarcange@redhat.com Subject: Re: [PATCH] sched,numa,mm: revert to checking pmd/pte_write instead of VMA flags Message-ID: <20160914092551.GA2745@suse.de> References: <20160908213053.07c992a9@annuminas.surriel.com> <20160911162402.GA2775@suse.de> <1473692983.32433.235.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1473692983.32433.235.camel@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 12, 2016 at 11:09:43AM -0400, Rik van Riel wrote: > > Patch looks ok other than the comment above the second hunk being out > > of > > date. Out of curiousity, what workload benefitted from this? I saw a > > mix > > of marginal results when I ran this on a 2-socket and 4-socket box. > > I did not performance test the change, because I believe > the VM_WRITE test has a small logical error. > > Specifically, VM_WRITE is also true for VMAs that are > PROT_WRITE|MAP_PRIVATE, which we do NOT want to group > on. Every shared library mapped on my system seems to > have a (small) read-write VMA: > Ok, while I agree with you, the patch is not a guaranteed win. However, in the event it is not, I agree that the problem will be with the grouping code. If the comment is updated then feel free to add my Acked-by: Mel Gorman