From patchwork Sun Dec 1 01:50:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11268247 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A378D921 for ; Sun, 1 Dec 2019 01:51:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6E8C1206E1 for ; Sun, 1 Dec 2019 01:51:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="bKRZdq74" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E8C1206E1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 510306B029C; Sat, 30 Nov 2019 20:51:02 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 4C1406B029E; Sat, 30 Nov 2019 20:51:02 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 387786B029F; Sat, 30 Nov 2019 20:51:02 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0057.hostedemail.com [216.40.44.57]) by kanga.kvack.org (Postfix) with ESMTP id 216066B029C for ; Sat, 30 Nov 2019 20:51:02 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id C9D7A2C8A for ; Sun, 1 Dec 2019 01:51:01 +0000 (UTC) X-FDA: 76214894322.20.songs61_8f276f79b230 X-Spam-Summary: 2,0,0,e5f2093291f7512b,d41d8cd98f00b204,akpm@linux-foundation.org,:akpm@linux-foundation.org:cai@lca.pw:jglisse@redhat.com:khlebnikov@yandex-team.ru:kirill.shutemov@linux.intel.com::mike.kravetz@oracle.com:mm-commits@vger.kernel.org:richardw.yang@linux.intel.com:riel@surriel.com:shakeelb@google.com:torvalds@linux-foundation.org,RULES_HIT:41:152:355:379:800:960:967:973:988:989:1260:1263:1277:1311:1313:1314:1345:1381:1431:1437:1513:1515:1516:1518:1521:1534:1542:1593:1594:1711:1730:1747:1777:1792:1969:2195:2199:2393:2525:2553:2559:2563:2682:2685:2693:2859:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3354:3865:3866:3867:3868:3870:3871:3872:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:5007:6119:6261:6653:6737:7576:7903:8599:9025:9207:9545:10004:10394:10400:10913:11026:11658:11914:12043:12048:12296:12297:12438:12517:12519:12555:12679:12783:12986:14181:14721:14849:14915:21080:21222:21324:21451:21627:21789:21795:21939:30051:3005 4:30064: X-HE-Tag: songs61_8f276f79b230 X-Filterd-Recvd-Size: 4331 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Sun, 1 Dec 2019 01:51:01 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 632C6206F0; Sun, 1 Dec 2019 01:51:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575165060; bh=JPgyu+DkpPaPHfSVib9rQetv+Rugns2LUUxAYmLW97Y=; h=Date:From:To:Subject:From; b=bKRZdq74uuaAzF1ihQhx4TQimw7wcqJZT32lcFZTQofyNICAWFPcDsWkIntBE97jU 8OTfSkmiGCxCp9M7zkptZ17BMlQBcgp/ZX3LYL+Xp6VzikwOdtl2ng4DFpieN10Qg3 eNm56TV2ZgbhAePaG/zILclDoXe6MOWMwoFHhXps= Date: Sat, 30 Nov 2019 17:50:59 -0800 From: akpm@linux-foundation.org To: akpm@linux-foundation.org, cai@lca.pw, jglisse@redhat.com, khlebnikov@yandex-team.ru, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, richardw.yang@linux.intel.com, riel@surriel.com, shakeelb@google.com, torvalds@linux-foundation.org Subject: [patch 035/158] mm/rmap.c: reuse mergeable anon_vma as parent when fork Message-ID: <20191201015059.JAkRF-SAj%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Wei Yang Subject: mm/rmap.c: reuse mergeable anon_vma as parent when fork In __anon_vma_prepare(), we will try to find anon_vma if it is possible to reuse it. While on fork, the logic is different. Since commit 5beb49305251 ("mm: change anon_vma linking to fix multi-process server scalability issue"), function anon_vma_clone() tries to allocate new anon_vma for child process. But the logic here will allocate a new anon_vma for each vma, even in parent this vma is mergeable and share the same anon_vma with its sibling. This may do better for scalability issue, while it is not necessary to do so especially after interval tree is used. Commit 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy") tries to reuse some anon_vma by counting child anon_vma and attached vmas. While for those mergeable anon_vmas, we can just reuse it and not necessary to go through the logic. After this change, kernel build test reduces 20% anon_vma allocation. Do the same kernel build test, it shows run time in sys reduced 11.6%. 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 2m39.933s user 17m1.835s sys 1m38.802s real 2m39.321s user 17m1.634s sys 1m39.206s real 2m39.575s user 17m1.420s sys 1m38.845s Link: http://lkml.kernel.org/r/20191011072256.16275-2-richardw.yang@linux.intel.com Signed-off-by: Wei Yang Acked-by: Konstantin Khlebnikov Cc: Kirill A. Shutemov Cc: "Jérôme Glisse" Cc: Mike Kravetz Cc: Rik van Riel Cc: Qian Cai Cc: Shakeel Butt Signed-off-by: Andrew Morton --- mm/rmap.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/mm/rmap.c~mm-rmapc-reuse-mergeable-anon_vma-as-parent-when-fork +++ a/mm/rmap.c @@ -269,6 +269,19 @@ int anon_vma_clone(struct vm_area_struct { struct anon_vma_chain *avc, *pavc; struct anon_vma *root = NULL; + struct vm_area_struct *prev = dst->vm_prev, *pprev = src->vm_prev; + + /* + * If parent share anon_vma with its vm_prev, keep this sharing in in + * child. + * + * 1. Parent has vm_prev, which implies we have vm_prev. + * 2. Parent and its vm_prev have the same anon_vma. + */ + if (!dst->anon_vma && src->anon_vma && + pprev && pprev->anon_vma == src->anon_vma) + dst->anon_vma = prev->anon_vma; + list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) { struct anon_vma *anon_vma;