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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2009-06-17 16:27:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-18 13:03:47 -0700
commit8a9478ca7f4bcb8945cec7f95d52dae2d5e50cbd (patch)
tree935e6ee3340ebe999374b54967cc2fa14e8d0060 /mm/swapfile.c
parent20ebcdda78a282d1d5266887ddf8a2d670182576 (diff)
memcg: fix swap accounting
This patch fixes mis-accounting of swap usage in memcg. In the current implementation, memcg's swap account is uncharged only when swap is completely freed. But there are several cases where swap cannot be freed cleanly. For handling that, this patch changes that memcg uncharges swap account when swap has no references other than cache. By this, memcg's swap entry accounting can be fully synchronous with the application's behavior. This patch also changes memcg's hooks for swap-out. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Balbir Singh <balbir@in.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swapfile.c')
-rw-r--r--mm/swapfile.c16
1 files changed, 12 insertions, 4 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 28faa01cf57..d1ade1a48ee 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -583,8 +583,9 @@ static int swap_entry_free(struct swap_info_struct *p,
swap_list.next = p - swap_info;
nr_swap_pages++;
p->inuse_pages--;
- mem_cgroup_uncharge_swap(ent);
}
+ if (!swap_count(count))
+ mem_cgroup_uncharge_swap(ent);
return count;
}
@@ -609,12 +610,19 @@ void swap_free(swp_entry_t entry)
void swapcache_free(swp_entry_t entry, struct page *page)
{
struct swap_info_struct *p;
+ int ret;
- if (page)
- mem_cgroup_uncharge_swapcache(page, entry);
p = swap_info_get(entry);
if (p) {
- swap_entry_free(p, entry, SWAP_CACHE);
+ ret = swap_entry_free(p, entry, SWAP_CACHE);
+ if (page) {
+ bool swapout;
+ if (ret)
+ swapout = true; /* the end of swap out */
+ else
+ swapout = false; /* no more swap users! */
+ mem_cgroup_uncharge_swapcache(page, entry, swapout);
+ }
spin_unlock(&swap_lock);
}
return;