From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f44.google.com (mail-pa0-f44.google.com [209.85.220.44]) by kanga.kvack.org (Postfix) with ESMTP id 744D2828DF for ; Wed, 3 Feb 2016 10:42:03 -0500 (EST) Received: by mail-pa0-f44.google.com with SMTP id uo6so15566325pac.1 for ; Wed, 03 Feb 2016 07:42:03 -0800 (PST) Received: from mga04.intel.com (mga04.intel.com. [192.55.52.120]) by mx.google.com with ESMTP id r138si10011718pfr.8.2016.02.03.07.42.02 for ; Wed, 03 Feb 2016 07:42:02 -0800 (PST) Subject: Re: [PATCH 4/4] thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers References: <1454512459-94334-1-git-send-email-kirill.shutemov@linux.intel.com> <1454512459-94334-5-git-send-email-kirill.shutemov@linux.intel.com> From: Dave Hansen Message-ID: <56B21FC9.9040009@intel.com> Date: Wed, 3 Feb 2016 07:42:01 -0800 MIME-Version: 1.0 In-Reply-To: <1454512459-94334-5-git-send-email-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli Cc: Hugh Dickins , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org On 02/03/2016 07:14 AM, Kirill A. Shutemov wrote: > But the new variant is somewhat slower. Current helpers iterates over > VMAs the compound page is mapped to, and then over ptes within this VMA. > New helpers iterates over small page, then over VMA the small page > mapped to, and only then find relevant pte. The code simplification here is really attractive. Can you quantify what the slowdown is? Is it noticeable, or would it be in the noise during all the other stuff that happens under memory pressure? -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757164AbcBCPmb (ORCPT ); Wed, 3 Feb 2016 10:42:31 -0500 Received: from mga14.intel.com ([192.55.52.115]:61560 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756495AbcBCPma (ORCPT ); Wed, 3 Feb 2016 10:42:30 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,391,1449561600"; d="scan'208";a="904773565" Subject: Re: [PATCH 4/4] thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers To: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli References: <1454512459-94334-1-git-send-email-kirill.shutemov@linux.intel.com> <1454512459-94334-5-git-send-email-kirill.shutemov@linux.intel.com> Cc: Hugh Dickins , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org From: Dave Hansen Message-ID: <56B21FC9.9040009@intel.com> Date: Wed, 3 Feb 2016 07:42:01 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1454512459-94334-5-git-send-email-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/03/2016 07:14 AM, Kirill A. Shutemov wrote: > But the new variant is somewhat slower. Current helpers iterates over > VMAs the compound page is mapped to, and then over ptes within this VMA. > New helpers iterates over small page, then over VMA the small page > mapped to, and only then find relevant pte. The code simplification here is really attractive. Can you quantify what the slowdown is? Is it noticeable, or would it be in the noise during all the other stuff that happens under memory pressure?