mm: swapfile: clean up unuse_pte race handling
Johannes Weiner [Tue, 31 Jul 2012 23:45:28 +0000 (16:45 -0700)]
The conditional mem_cgroup_cancel_charge_swapin() is a leftover from when
the function would continue to reestablish the page even after
mem_cgroup_try_charge_swapin() failed.  After 85d9fc8 "memcg: fix refcnt
handling at swapoff", the condition is always true when this code is
reached.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Wanpeng Li <liwp.linux@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c

index 63958d6..14e254c 100644 (file)
@@ -835,8 +835,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 
        pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
        if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) {
-               if (ret > 0)
-                       mem_cgroup_cancel_charge_swapin(memcg);
+               mem_cgroup_cancel_charge_swapin(memcg);
                ret = 0;
                goto out;
        }