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author | Joonsoo Kim <iamjoonsoo.kim@lge.com> | 2014-01-22 00:49:53 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-22 01:19:45 +0100 |
commit | 9f32624be943538983eb0f18b73a9052d1493c80 (patch) | |
tree | 990e19eac9ef2534e8fc0909ff7f8aabc9a09d00 /mm/ksm.c | |
parent | mm/rmap: use rmap_walk() in try_to_munlock() (diff) | |
download | linux-9f32624be943538983eb0f18b73a9052d1493c80.tar.xz linux-9f32624be943538983eb0f18b73a9052d1493c80.zip |
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 <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/ksm.c')
-rw-r--r-- | mm/ksm.c | 60 |
1 files changed, 5 insertions, 55 deletions
@@ -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); |