From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758801Ab2JZN3A (ORCPT ); Fri, 26 Oct 2012 09:29:00 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:44611 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752825Ab2JZN27 (ORCPT ); Fri, 26 Oct 2012 09:28:59 -0400 Date: Fri, 26 Oct 2012 15:28:53 +0200 From: Ingo Molnar To: Rik van Riel Cc: Andi Kleen , Michel Lespinasse , Linus Torvalds , Peter Zijlstra , Andrea Arcangeli , Mel Gorman , Johannes Weiner , Thomas Gleixner , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 05/31] x86/mm: Reduce tlb flushes from ptep_set_access_flags() Message-ID: <20121026132853.GA11178@gmail.com> References: <20121025124832.840241082@chello.nl> <5089F5B5.1050206@redhat.com> <508A0A0D.4090001@redhat.com> <508A8D31.9000106@redhat.com> <20121026132601.GC9886@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121026132601.GC9886@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > [...] > > Rik, mind sending an updated patch that addresses Linus's > concerns, or should I code it up if you are busy? > > We can also certainly try the second patch, but I'd do it at > the end of the series, to put some tree distance between the > two patches, to not concentrate regression risks too tightly > in the Git space, to help out with hard to bisect problems... I'd also like to have the second patch separately because I'd like to measure spurious fault frequency before and after the change, with a reference workload. Just a single page fault, even it's a minor one, might make a micro-optimization a net loss. INVLPG might be the cheaper option on average - it needs to be measured. (I'll do that, just please keep it separate from the main TLB-flush optimization.) Thanks, Ingo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx149.postini.com [74.125.245.149]) by kanga.kvack.org (Postfix) with SMTP id 8A82B6B0072 for ; Fri, 26 Oct 2012 09:28:59 -0400 (EDT) Received: by mail-ee0-f41.google.com with SMTP id c4so1272830eek.14 for ; Fri, 26 Oct 2012 06:28:57 -0700 (PDT) Date: Fri, 26 Oct 2012 15:28:53 +0200 From: Ingo Molnar Subject: Re: [PATCH 05/31] x86/mm: Reduce tlb flushes from ptep_set_access_flags() Message-ID: <20121026132853.GA11178@gmail.com> References: <20121025124832.840241082@chello.nl> <5089F5B5.1050206@redhat.com> <508A0A0D.4090001@redhat.com> <508A8D31.9000106@redhat.com> <20121026132601.GC9886@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121026132601.GC9886@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: Andi Kleen , Michel Lespinasse , Linus Torvalds , Peter Zijlstra , Andrea Arcangeli , Mel Gorman , Johannes Weiner , Thomas Gleixner , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org * Ingo Molnar wrote: > [...] > > Rik, mind sending an updated patch that addresses Linus's > concerns, or should I code it up if you are busy? > > We can also certainly try the second patch, but I'd do it at > the end of the series, to put some tree distance between the > two patches, to not concentrate regression risks too tightly > in the Git space, to help out with hard to bisect problems... I'd also like to have the second patch separately because I'd like to measure spurious fault frequency before and after the change, with a reference workload. Just a single page fault, even it's a minor one, might make a micro-optimization a net loss. INVLPG might be the cheaper option on average - it needs to be measured. (I'll do that, just please keep it separate from the main TLB-flush optimization.) Thanks, Ingo -- 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