From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754755Ab1LIVXf (ORCPT ); Fri, 9 Dec 2011 16:23:35 -0500 Received: from mail-qw0-f53.google.com ([209.85.216.53]:49191 "EHLO mail-qw0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752027Ab1LIVXe (ORCPT ); Fri, 9 Dec 2011 16:23:34 -0500 From: kosaki.motohiro@gmail.com To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: KOSAKI Motohiro , Andrew Morton (commit_signer:15/23=65%), Hugh Dickins (commit_signer:7/23=30%), Peter Zijlstra (commit_signer:4/23=17%), Shaohua Li (commit_signer:3/23=13%) Subject: [PATCH v2] mm: simplify find_vma_prev Date: Fri, 9 Dec 2011 16:23:00 -0500 Message-Id: <1323465781-2976-1-git-send-email-kosaki.motohiro@gmail.com> X-Mailer: git-send-email 1.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KOSAKI Motohiro commit 297c5eee37 (mm: make the vma list be doubly linked) added vm_prev member into vm_area_struct. Therefore we can simplify find_vma_prev() by using it. Also, this change help to improve page fault performance because it has strong locality of reference. Signed-off-by: KOSAKI Motohiro --- mm/mmap.c | 40 +++++++++++----------------------------- 1 files changed, 11 insertions(+), 29 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index eae90af..a84539b 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1603,39 +1603,21 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) EXPORT_SYMBOL(find_vma); -/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ +/* + * Same as find_vma, but also return a pointer to the previous VMA in *pprev. + * Note: pprev is set to NULL when return value is NULL. + */ struct vm_area_struct * -find_vma_prev(struct mm_struct *mm, unsigned long addr, - struct vm_area_struct **pprev) +find_vma_prev(struct mm_struct *mm, unsigned long addr, struct vm_area_struct **pprev) { - struct vm_area_struct *vma = NULL, *prev = NULL; - struct rb_node *rb_node; - if (!mm) - goto out; - - /* Guard against addr being lower than the first VMA */ - vma = mm->mmap; - - /* Go through the RB tree quickly. */ - rb_node = mm->mm_rb.rb_node; - - while (rb_node) { - struct vm_area_struct *vma_tmp; - vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); + struct vm_area_struct *vma; - if (addr < vma_tmp->vm_end) { - rb_node = rb_node->rb_left; - } else { - prev = vma_tmp; - if (!prev->vm_next || (addr < prev->vm_next->vm_end)) - break; - rb_node = rb_node->rb_right; - } - } + *pprev = NULL; + vma = find_vma(mm, addr); + if (vma) + *pprev = vma->vm_prev; -out: - *pprev = prev; - return prev ? prev->vm_next : vma; + return vma; } /* -- 1.7.1