From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753393AbdHKQGn (ORCPT ); Fri, 11 Aug 2017 12:06:43 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:42606 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752703AbdHKQGl (ORCPT ); Fri, 11 Aug 2017 12:06:41 -0400 Subject: Re: [v6 09/15] sparc64: optimized struct page zeroing To: Michal Hocko Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, kasan-dev@googlegroups.com, borntraeger@de.ibm.com, heiko.carstens@de.ibm.com, davem@davemloft.net, willy@infradead.org, ard.biesheuvel@linaro.org, will.deacon@arm.com, catalin.marinas@arm.com, sam@ravnborg.org References: <1502138329-123460-1-git-send-email-pasha.tatashin@oracle.com> <1502138329-123460-10-git-send-email-pasha.tatashin@oracle.com> <20170811125326.GK30811@dhcp22.suse.cz> From: Pasha Tatashin Message-ID: <3830e513-cb35-e52e-341c-25eaecc51d43@oracle.com> Date: Fri, 11 Aug 2017 12:04:51 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20170811125326.GK30811@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> Add an optimized mm_zero_struct_page(), so struct page's are zeroed without >> calling memset(). We do eight to tent regular stores based on the size of >> struct page. Compiler optimizes out the conditions of switch() statement. > > Again, this doesn't explain why we need this. You have mentioned those > reasons in some previous emails but be explicit here please. > I will add performance data to this patch as well. Thank you, Pasha