From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82216C4360C for ; Sat, 5 Oct 2019 01:16:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D6B621D81 for ; Sat, 5 Oct 2019 01:16:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="TV6E3RyA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726137AbfJEBQF (ORCPT ); Fri, 4 Oct 2019 21:16:05 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:35838 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725730AbfJEBQF (ORCPT ); Fri, 4 Oct 2019 21:16:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=76PvWG28Wf5VWGGq/eiwJm/zoctdt2tMBJW16pZ6SJc=; b=TV6E3RyA/PqAV8ahjRwF6ETx9 6sk0zSIkxCy4Z3dxHFslxT3InYPSUf4cGpcRTAkajsnvOdUtLrnjgXsS5/xH92dtbMcHN5fBrz88F sAm+/YpYsbOpMy86xSe4sL9SoRQudK0ENoQg4lI7rCwR0Fj3p8fhV3ZFlQUOeoHDsGPg2aYe1+Ho/ vAgMN4GJ36AMyFNm1My9bqkO0nPblSBrZYaSpkOpneegQHnyUnFGuI76xnWDnTQbpIR8MMyA+dRiA nkxIVB7hMYSxXaRVs5dYYmdETxn6O4/xF6Pa1lljqxFDTNPBa0N5DismyJ1nD8HFP2vPnWZKd/0sh ABmCfqSig==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.2 #3 (Red Hat Linux)) id 1iGYfq-0001PH-7v; Sat, 05 Oct 2019 01:15:54 +0000 Date: Fri, 4 Oct 2019 18:15:54 -0700 From: Matthew Wilcox To: Wei Yang Cc: akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, jglisse@redhat.com, mike.kravetz@oracle.com, riel@surriel.com, khlebnikov@yandex-team.ru, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/rmap.c: reuse mergeable anon_vma as parent when fork Message-ID: <20191005011554.GQ32665@bombadil.infradead.org> References: <20191004160632.30251-1-richardw.yang@linux.intel.com> <20191004161120.GI32665@bombadil.infradead.org> <20191004234845.GB15415@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191004234845.GB15415@richard> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 05, 2019 at 07:48:45AM +0800, Wei Yang wrote: > On Fri, Oct 04, 2019 at 09:11:20AM -0700, Matthew Wilcox wrote: > >On Sat, Oct 05, 2019 at 12:06:32AM +0800, Wei Yang wrote: > >> After this change, kernel build test reduces 20% anon_vma allocation. > > > >But does it have any effect on elapsed time or peak memory consumption? > > Do the same kernel build test and record time: > > > Origin > > real 2m50.467s > user 17m52.002s > sys 1m51.953s > > real 2m48.662s > user 17m55.464s > sys 1m50.553s > > real 2m51.143s > user 17m59.687s > sys 1m53.600s > > > Patched > > real 2m43.733s > user 17m25.705s > sys 1m41.791s > > real 2m47.146s > user 17m47.451s > sys 1m43.474s > > real 2m45.763s > user 17m38.230s > sys 1m42.102s > > > For time in sys, it reduced 8.5%. That's compelling!