From 012f18004da33ba672e3c60838cc4898126174d3 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Mon, 9 Aug 2010 17:18:40 -0700 Subject: mm: always lock the root (oldest) anon_vma Always (and only) lock the root (oldest) anon_vma whenever we do something in an anon_vma. The recently introduced anon_vma scalability is due to the rmap code scanning only the VMAs that need to be scanned. Many common operations still took the anon_vma lock on the root anon_vma, so always taking that lock is not expected to introduce any scalability issues. However, always taking the same lock does mean we only need to take one lock, which means rmap_walk on pages from any anon_vma in the vma is excluded from occurring during an munmap, expand_stack or other operation that needs to exclude rmap_walk and similar functions. Also add the proper locking to vma_adjust. Signed-off-by: Rik van Riel Tested-by: Larry Woodman Acked-by: Larry Woodman Reviewed-by: Minchan Kim Reviewed-by: KAMEZAWA Hiroyuki Acked-by: Mel Gorman Acked-by: Linus Torvalds Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/rmap.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux/rmap.h') diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 41fa6ddc6214..af43cb9a0506 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -104,24 +104,24 @@ static inline void vma_lock_anon_vma(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; if (anon_vma) - spin_lock(&anon_vma->lock); + spin_lock(&anon_vma->root->lock); } static inline void vma_unlock_anon_vma(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; if (anon_vma) - spin_unlock(&anon_vma->lock); + spin_unlock(&anon_vma->root->lock); } static inline void anon_vma_lock(struct anon_vma *anon_vma) { - spin_lock(&anon_vma->lock); + spin_lock(&anon_vma->root->lock); } static inline void anon_vma_unlock(struct anon_vma *anon_vma) { - spin_unlock(&anon_vma->lock); + spin_unlock(&anon_vma->root->lock); } /* -- cgit v1.2.3-59-g8ed1b