From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947125AbeCBSAa (ORCPT ); Fri, 2 Mar 2018 13:00:30 -0500 Received: from mga02.intel.com ([134.134.136.20]:9986 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1947104AbeCBSA0 (ORCPT ); Fri, 2 Mar 2018 13:00:26 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,413,1515484800"; d="scan'208";a="35471163" Subject: Re: [PATCH v4 3/3] mm/free_pcppages_bulk: prefetch buddy while not holding lock To: Vlastimil Babka , Michal Hocko , Aaron Lu References: <20180301062845.26038-1-aaron.lu@intel.com> <20180301062845.26038-4-aaron.lu@intel.com> <20180301140044.GK15057@dhcp22.suse.cz> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Huang Ying , Kemi Wang , Tim Chen , Andi Kleen , Mel Gorman , Matthew Wilcox , David Rientjes From: Dave Hansen Message-ID: <2433e857-fea7-9af4-d124-538ad17de454@intel.com> Date: Fri, 2 Mar 2018 10:00:24 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/02/2018 09:55 AM, Vlastimil Babka wrote: > It's even stranger to me. Struct page is 64 bytes these days, exactly a > a cache line. Unless that changed, Intel CPUs prefetched a "buddy" cache > line (that forms an aligned 128 bytes block with the one we touch). I believe that was a behavior that was specific to the Pentium 4 "Netburst" era. I don't think the 128-byte line behavior exists on modern Intel cpus. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 028C36B000E for ; Fri, 2 Mar 2018 13:00:28 -0500 (EST) Received: by mail-pf0-f197.google.com with SMTP id d5so2795428pfn.12 for ; Fri, 02 Mar 2018 10:00:27 -0800 (PST) Received: from mga17.intel.com (mga17.intel.com. [192.55.52.151]) by mx.google.com with ESMTPS id bj2-v6si5117666plb.286.2018.03.02.10.00.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 02 Mar 2018 10:00:27 -0800 (PST) Subject: Re: [PATCH v4 3/3] mm/free_pcppages_bulk: prefetch buddy while not holding lock References: <20180301062845.26038-1-aaron.lu@intel.com> <20180301062845.26038-4-aaron.lu@intel.com> <20180301140044.GK15057@dhcp22.suse.cz> From: Dave Hansen Message-ID: <2433e857-fea7-9af4-d124-538ad17de454@intel.com> Date: Fri, 2 Mar 2018 10:00:24 -0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka , Michal Hocko , Aaron Lu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Huang Ying , Kemi Wang , Tim Chen , Andi Kleen , Mel Gorman , Matthew Wilcox , David Rientjes On 03/02/2018 09:55 AM, Vlastimil Babka wrote: > It's even stranger to me. Struct page is 64 bytes these days, exactly a > a cache line. Unless that changed, Intel CPUs prefetched a "buddy" cache > line (that forms an aligned 128 bytes block with the one we touch). I believe that was a behavior that was specific to the Pentium 4 "Netburst" era. I don't think the 128-byte line behavior exists on modern Intel cpus. -- 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