From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f173.google.com (mail-wi0-f173.google.com [209.85.212.173]) by kanga.kvack.org (Postfix) with ESMTP id 87AC86B0035 for ; Tue, 1 Jul 2014 17:52:12 -0400 (EDT) Received: by mail-wi0-f173.google.com with SMTP id cc10so8603625wib.6 for ; Tue, 01 Jul 2014 14:52:12 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id v8si29632134wjq.85.2014.07.01.14.52.10 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 01 Jul 2014 14:52:11 -0700 (PDT) Date: Tue, 1 Jul 2014 17:51:56 -0400 From: Naoya Horiguchi Subject: Re: [PATCH v4 11/13] mempolicy: apply page table walker on queue_pages_range() Message-ID: <20140701215156.GA21032@nhori.bos.redhat.com> References: <1404234451-21695-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1404234451-21695-12-git-send-email-n-horiguchi@ah.jp.nec.com> <53B32170.1040707@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53B32170.1040707@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: linux-mm@kvack.org, Andrew Morton , Hugh Dickins , "Kirill A. Shutemov" , Jerome Marchand , linux-kernel@vger.kernel.org, Naoya Horiguchi , Jet Chen On Tue, Jul 01, 2014 at 02:00:32PM -0700, Dave Hansen wrote: > On 07/01/2014 10:07 AM, Naoya Horiguchi wrote: > > queue_pages_range() does page table walking in its own way now, but there > > is some code duplicate. This patch applies page table walker to reduce > > lines of code. > > > > queue_pages_range() has to do some precheck to determine whether we really > > walk over the vma or just skip it. Now we have test_walk() callback in > > mm_walk for this purpose, so we can do this replacement cleanly. > > queue_pages_test_walk() depends on not only the current vma but also the > > previous one, so queue_pages->prev is introduced to remember it. > > Hi Naoya, > > The previous version of this patch caused a performance regression which > was reported to you: > > http://marc.info/?l=linux-kernel&m=140375975525069&w=2 > > Has that been dealt with in this version somehow? I believe so, in previous version we called ->pte_entry() callback for each pte entries, but in this version I stop doing this and most of works are done in ->pmd_entry() callback, so the number of function calls are reduced by about 1/512. And rather than that, I just cleaned up queue_pages_* without major behavioral changes, so the visible regression should be solved. Thanks, Naoya Horiguchi -- 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