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| author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2012-01-10 15:08:07 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-10 16:30:44 -0800 |
| commit | 6bd4837de96e7d9f9bf33e59117c24fc230862ac (patch) | |
| tree | 633d23438e31aeef61063c6de490cc5696f4e5f5 /mm | |
| parent | 948f017b093a9baac23855fcd920d3a970b71bb6 (diff) | |
| download | linux-6bd4837de96e7d9f9bf33e59117c24fc230862ac.tar.bz2 | |
mm: simplify find_vma_prev()
commit 297c5eee37 ("mm: make the vma list be doubly linked") added the
vm_prev member to vm_area_struct. We can simplify find_vma_prev() by
using it. Also, this change helps to improve page fault performance
because it has stronger locality of reference.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mmap.c | 36 |
1 files changed, 8 insertions, 28 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index adea3b8880e3..3f758c7f4c81 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1603,39 +1603,19 @@ 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) { - 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); - - 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; - } - } + struct vm_area_struct *vma; -out: - *pprev = prev; - return prev ? prev->vm_next : vma; + vma = find_vma(mm, addr); + *pprev = vma ? vma->vm_prev : NULL; + return vma; } /* |