From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx177.postini.com [74.125.245.177]) by kanga.kvack.org (Postfix) with SMTP id 65BDE6B004D for ; Fri, 9 Dec 2011 15:09:37 -0500 (EST) Received: by qan41 with SMTP id 41so2104961qan.14 for ; Fri, 09 Dec 2011 12:09:36 -0800 (PST) From: kosaki.motohiro@gmail.com Subject: [PATCH] mm: simplify find_vma_prev Date: Fri, 9 Dec 2011 15:09:04 -0500 Message-Id: <1323461345-12805-1-git-send-email-kosaki.motohiro@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: KOSAKI Motohiro , Andrew Morton , Hugh Dickins , Peter Zijlstra , Shaohua Li 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 imporove page fault performance becuase it has strong locality of reference. Signed-off-by: KOSAKI Motohiro --- mm/mmap.c | 34 ++++++---------------------------- 1 files changed, 6 insertions(+), 28 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index eae90af..955750c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1605,37 +1605,15 @@ EXPORT_SYMBOL(find_vma); /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ 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; - } - } + 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org