From 9f32624be943538983eb0f18b73a9052d1493c80 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Tue, 21 Jan 2014 15:49:53 -0800 Subject: mm/rmap: use rmap_walk() in page_referenced() Now, we have an infrastructure in rmap_walk() to handle difference from variants of rmap traversing functions. So, just use it in page_referenced(). In this patch, I change following things. 1. remove some variants of rmap traversing functions. cf> page_referenced_ksm, page_referenced_anon, page_referenced_file 2. introduce new struct page_referenced_arg and pass it to page_referenced_one(), main function of rmap_walk, in order to count reference, to store vm_flags and to check finish condition. 3. mechanical change to use rmap_walk() in page_referenced(). [liwanp@linux.vnet.ibm.com: fix BUG at rmap_walk] Signed-off-by: Joonsoo Kim Reviewed-by: Naoya Horiguchi Cc: Mel Gorman Cc: Hugh Dickins Cc: Rik van Riel Cc: Ingo Molnar Cc: Hillf Danton Signed-off-by: Wanpeng Li Cc: Sasha Levin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/ksm.c | 60 +++++------------------------------------------------------- 1 file changed, 5 insertions(+), 55 deletions(-) (limited to 'mm/ksm.c') diff --git a/mm/ksm.c b/mm/ksm.c index 646d45a6b6c8..3df141e5f3e0 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1891,61 +1891,6 @@ struct page *ksm_might_need_to_copy(struct page *page, return new_page; } -int page_referenced_ksm(struct page *page, struct mem_cgroup *memcg, - unsigned long *vm_flags) -{ - struct stable_node *stable_node; - struct rmap_item *rmap_item; - unsigned int mapcount = page_mapcount(page); - int referenced = 0; - int search_new_forks = 0; - - VM_BUG_ON(!PageKsm(page)); - VM_BUG_ON(!PageLocked(page)); - - stable_node = page_stable_node(page); - if (!stable_node) - return 0; -again: - hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) { - struct anon_vma *anon_vma = rmap_item->anon_vma; - struct anon_vma_chain *vmac; - struct vm_area_struct *vma; - - anon_vma_lock_read(anon_vma); - anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, - 0, ULONG_MAX) { - vma = vmac->vma; - if (rmap_item->address < vma->vm_start || - rmap_item->address >= vma->vm_end) - continue; - /* - * Initially we examine only the vma which covers this - * rmap_item; but later, if there is still work to do, - * we examine covering vmas in other mms: in case they - * were forked from the original since ksmd passed. - */ - if ((rmap_item->mm == vma->vm_mm) == search_new_forks) - continue; - - if (memcg && !mm_match_cgroup(vma->vm_mm, memcg)) - continue; - - referenced += page_referenced_one(page, vma, - rmap_item->address, &mapcount, vm_flags); - if (!search_new_forks || !mapcount) - break; - } - anon_vma_unlock_read(anon_vma); - if (!mapcount) - goto out; - } - if (!search_new_forks++) - goto again; -out: - return referenced; -} - int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) { struct stable_node *stable_node; @@ -1954,6 +1899,11 @@ int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) int search_new_forks = 0; VM_BUG_ON(!PageKsm(page)); + + /* + * Rely on the page lock to protect against concurrent modifications + * to that page's node of the stable tree. + */ VM_BUG_ON(!PageLocked(page)); stable_node = page_stable_node(page); -- cgit v1.2.3-55-g7522