From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id 83DE16B04D9 for ; Tue, 11 Jul 2017 05:45:27 -0400 (EDT) Received: by mail-pg0-f69.google.com with SMTP id g14so143633899pgu.9 for ; Tue, 11 Jul 2017 02:45:27 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id a61si11031632pla.145.2017.07.11.02.45.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 Jul 2017 02:45:26 -0700 (PDT) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v6B9ippD025963 for ; Tue, 11 Jul 2017 05:45:26 -0400 Received: from e23smtp06.au.ibm.com (e23smtp06.au.ibm.com [202.81.31.148]) by mx0a-001b2d01.pphosted.com with ESMTP id 2bmbyy0myu-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 11 Jul 2017 05:45:25 -0400 Received: from localhost by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 11 Jul 2017 19:45:21 +1000 Received: from d23av05.au.ibm.com (d23av05.au.ibm.com [9.190.234.119]) by d23relay10.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v6B9jAkt12714096 for ; Tue, 11 Jul 2017 19:45:18 +1000 Received: from d23av05.au.ibm.com (localhost [127.0.0.1]) by d23av05.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v6B9ijbh031317 for ; Tue, 11 Jul 2017 19:44:46 +1000 Subject: Re: [RFC] mm/mremap: Remove redundant checks inside vma_expandable() References: <20170710111059.30795-1-khandual@linux.vnet.ibm.com> <20170710134917.GB19645@dhcp22.suse.cz> <20170711060354.GA24852@dhcp22.suse.cz> <4c182da0-6c84-df67-b173-6960fac0544a@suse.cz> From: Anshuman Khandual Date: Tue, 11 Jul 2017 15:14:27 +0530 MIME-Version: 1.0 In-Reply-To: <4c182da0-6c84-df67-b173-6960fac0544a@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Message-Id: <210533b7-3b29-b6bd-24db-03e0c756a882@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka , Michal Hocko , Anshuman Khandual Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, mike.kravetz@oracle.com On 07/11/2017 11:56 AM, Vlastimil Babka wrote: > On 07/11/2017 08:03 AM, Michal Hocko wrote: >> On Tue 11-07-17 09:58:42, Anshuman Khandual wrote: >>>> here. This is hardly something that would save many cycles in a >>>> relatively cold path. >>> Though I have not done any detailed instruction level measurement, >>> there is a reduction in real and system amount of time to execute >>> the test with and without the patch. >>> >>> Without the patch >>> >>> real 0m2.100s >>> user 0m0.162s >>> sys 0m1.937s >>> >>> With this patch >>> >>> real 0m0.928s >>> user 0m0.161s >>> sys 0m0.756s >> Are you telling me that two if conditions cause more than a second >> difference? That sounds suspicious. > It's removing also a call to get_unmapped_area(), AFAICS. That means a > vma search? I believe removing this function is responsible for the increase in speed of the test execution. -- 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