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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 81F28C432C0 for ; Mon, 18 Nov 2019 13:22:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EB46206D4 for ; Mon, 18 Nov 2019 13:22:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727020AbfKRNWs (ORCPT ); Mon, 18 Nov 2019 08:22:48 -0500 Received: from mga12.intel.com ([192.55.52.136]:64926 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726284AbfKRNWs (ORCPT ); Mon, 18 Nov 2019 08:22:48 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Nov 2019 05:22:47 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,320,1569308400"; d="scan'208";a="236915582" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga002.fm.intel.com with ESMTP; 18 Nov 2019 05:22:45 -0800 Date: Mon, 18 Nov 2019 21:22:35 +0800 From: Wei Yang To: linmiaohe Cc: akpm@linux-foundation.org, richardw.yang@linux.intel.com, sfr@canb.auug.org.au, rppt@linux.ibm.com, jannh@google.com, steve.capper@arm.com, catalin.marinas@arm.com, aarcange@redhat.com, walken@google.com, dave.hansen@linux.intel.com, tiny.windzz@gmail.com, jhubbard@nvidia.com, david@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4] mm: get rid of odd jump labels in find_mergeable_anon_vma() Message-ID: <20191118132235.GA28027@richard> Reply-To: Wei Yang References: <1574079844-17493-1-git-send-email-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1574079844-17493-1-git-send-email-linmiaohe@huawei.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 18, 2019 at 08:24:04PM +0800, linmiaohe wrote: >From: Miaohe Lin > >The jump labels try_prev and none are not really needed >in find_mergeable_anon_vma(), eliminate them to improve >readability. > >Reviewed-by: David Hildenbrand >Reviewed-by: John Hubbard >Signed-off-by: Miaohe Lin Reviewed-by: Wei Yang >--- >-v2: > Fix commit descriptions and further simplify the code > as suggested by David Hildenbrand and John Hubbard. >-v3: > Rewrite patch version info. Don't show this in commit log. >-v4: > Get rid of var near completely as well. >--- > mm/mmap.c | 36 ++++++++++++++++-------------------- > 1 file changed, 16 insertions(+), 20 deletions(-) > >diff --git a/mm/mmap.c b/mm/mmap.c >index 91d5e097a4ed..4d93bda30eac 100644 >--- a/mm/mmap.c >+++ b/mm/mmap.c >@@ -1273,26 +1273,22 @@ static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_ > */ > struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) > { >- struct anon_vma *anon_vma; >- struct vm_area_struct *near; >- >- near = vma->vm_next; >- if (!near) >- goto try_prev; >- >- anon_vma = reusable_anon_vma(near, vma, near); >- if (anon_vma) >- return anon_vma; >-try_prev: >- near = vma->vm_prev; >- if (!near) >- goto none; >- >- anon_vma = reusable_anon_vma(near, near, vma); >- if (anon_vma) >- return anon_vma; >-none: >+ struct anon_vma *anon_vma = NULL; >+ >+ /* Try next first. */ >+ if (vma->vm_next) { >+ anon_vma = reusable_anon_vma(vma->vm_next, vma, vma->vm_next); >+ if (anon_vma) >+ return anon_vma; >+ } >+ >+ /* Try prev next. */ >+ if (vma->vm_prev) >+ anon_vma = reusable_anon_vma(vma->vm_prev, vma->vm_prev, vma); >+ > /* >+ * We might reach here with anon_vma == NULL if we can't find >+ * any reusable anon_vma. > * There's no absolute need to look only at touching neighbours: > * we could search further afield for "compatible" anon_vmas. > * But it would probably just be a waste of time searching, >@@ -1300,7 +1296,7 @@ struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) > * We're trying to allow mprotect remerging later on, > * not trying to minimize memory used for anon_vmas. > */ >- return NULL; >+ return anon_vma; > } > > /* >-- >2.21.GIT -- Wei Yang Help you, Help me