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=-9.8 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_GIT autolearn=unavailable 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 4C627C433FF for ; Tue, 6 Aug 2019 08:19:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 275502070D for ; Tue, 6 Aug 2019 08:19:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732088AbfHFITK (ORCPT ); Tue, 6 Aug 2019 04:19:10 -0400 Received: from mga02.intel.com ([134.134.136.20]:35535 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728918AbfHFITJ (ORCPT ); Tue, 6 Aug 2019 04:19:09 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Aug 2019 01:11:50 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,352,1559545200"; d="scan'208";a="176561599" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga003.jf.intel.com with ESMTP; 06 Aug 2019 01:11:48 -0700 From: Wei Yang To: akpm@linux-foundation.org, mhocko@suse.com, vbabka@suse.cz, kirill.shutemov@linux.intel.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wei Yang Subject: [PATCH] mm/mmap.c: refine data locality of find_vma_prev Date: Tue, 6 Aug 2019 16:11:23 +0800 Message-Id: <20190806081123.22334-1-richardw.yang@linux.intel.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When addr is out of the range of the whole rb_tree, pprev will points to the biggest node. find_vma_prev gets is by going through the right most node of the tree. Since only the last node is the one it is looking for, it is not necessary to assign pprev to those middle stage nodes. By assigning pprev to the last node directly, it tries to improve the function locality a little. Signed-off-by: Wei Yang --- mm/mmap.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 7e8c3e8ae75f..284bc7e51f9c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2271,11 +2271,10 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr, *pprev = vma->vm_prev; } else { struct rb_node *rb_node = mm->mm_rb.rb_node; - *pprev = NULL; - while (rb_node) { - *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); + while (rb_node && rb_node->rb_right) rb_node = rb_node->rb_right; - } + *pprev = rb_node ? NULL + : rb_entry(rb_node, struct vm_area_struct, vm_rb); } return vma; } -- 2.17.1