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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-12-14 17:59:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-15 08:53:18 -0800
commit93d17715a5b960d34220f2edba3e6cee9b5b1c58 (patch)
tree9ab08ff4169464bf5b8d86c8082296fd6e3d069b /mm/ksm.c
parentvmscan: make consistent of reclaim bale out between do_try_to_free_page and shrink_zone (diff)
downloadlinux-dev-93d17715a5b960d34220f2edba3e6cee9b5b1c58.tar.xz
linux-dev-93d17715a5b960d34220f2edba3e6cee9b5b1c58.zip
ksm: three remove_rmap_item_from_tree cleanups
1. remove_rmap_item_from_tree() is called as a precaution from various places: don't dirty the rmap_item cacheline unnecessarily, just mask the flags out of the address when they have been set. 2. First get_next_rmap_item() removes an unstable rmap_item from its tree, then shortly afterwards cmp_and_merge_page() removes a stable rmap_item from its tree: it's easier just to do both at once (but definitely keep the BUG_ON(age > 1) which guards against a future omission). 3. When cmp_and_merge_page() moves an rmap_item from unstable to stable tree, it does its own rb_erase() and accounting: that's better expressed by remove_rmap_item_from_tree(). Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Izik Eidus <ieidus@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--mm/ksm.c17
1 files changed, 6 insertions, 11 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 5575f8628fef..133ea2ca8384 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -453,6 +453,7 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item)
}
rmap_item->next = NULL;
+ rmap_item->address &= PAGE_MASK;
} else if (rmap_item->address & NODE_FLAG) {
unsigned char age;
@@ -467,11 +468,11 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item)
BUG_ON(age > 1);
if (!age)
rb_erase(&rmap_item->node, &root_unstable_tree);
+
ksm_pages_unshared--;
+ rmap_item->address &= PAGE_MASK;
}
- rmap_item->address &= PAGE_MASK;
-
cond_resched(); /* we're called from many long loops */
}
@@ -1086,8 +1087,7 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)
unsigned int checksum;
int err;
- if (in_stable_tree(rmap_item))
- remove_rmap_item_from_tree(rmap_item);
+ remove_rmap_item_from_tree(rmap_item);
/* We first start with searching the page inside the stable tree */
tree_rmap_item = stable_tree_search(page, page2, rmap_item);
@@ -1143,9 +1143,7 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)
* tree, and insert it instead as new node in the stable tree.
*/
if (!err) {
- rb_erase(&tree_rmap_item->node, &root_unstable_tree);
- tree_rmap_item->address &= ~NODE_FLAG;
- ksm_pages_unshared--;
+ remove_rmap_item_from_tree(tree_rmap_item);
/*
* If we fail to insert the page into the stable tree,
@@ -1174,11 +1172,8 @@ static struct rmap_item *get_next_rmap_item(struct mm_slot *mm_slot,
while (cur != &mm_slot->rmap_list) {
rmap_item = list_entry(cur, struct rmap_item, link);
- if ((rmap_item->address & PAGE_MASK) == addr) {
- if (!in_stable_tree(rmap_item))
- remove_rmap_item_from_tree(rmap_item);
+ if ((rmap_item->address & PAGE_MASK) == addr)
return rmap_item;
- }
if (rmap_item->address > addr)
break;
cur = cur->next;