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Subject[PATCH -mm 2/5] memcg: handle swap cache
Now swapcache is not accounted. (because it had some troubles.)

This is retrying account swap cache, based on remove-refcnt patch.

* If a page is swap-cache, mem_cgroup_uncharge_page() will *not*
uncharge a page even if page->mapcount == 0.
* If a page is removed from swap-cache, mem_cgroup_uncharge_page()
is called.
* A new swapcache page is not charged until when it's mapped. By this
we can avoid complicated read-ahead troubles.

A file, memory.stat,"rss" member is changed to "anon/swapcache".
(rss is not precise name here...)
When all processes in cgroup exits, rss/swapcache counter can have some
numbers because of lazy behavior of LRU. So the word "rss" is confusing.

I can easily imagine a user says "Oh, there may be memory leak..."
Precise counting of swapcache will be tried in future (if necessary)

Change log: v3->v4
- adjusted to 2.6.26-rc2-mm1
Change log: v2->v3
- adjusted to 2.6.26-rc2+x
- changed "rss" in stat to "rss/swapcache". (stat value includes swapcache)
Change log: v1->v2
- adjusted to 2.6.25-mm1.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

---
mm/memcontrol.c | 9 +++++----
mm/migrate.c | 3 ++-
mm/swap_state.c | 1 +
3 files changed, 8 insertions(+), 5 deletions(-)

Index: mm-2.6.26-rc2-mm1/mm/migrate.c
===================================================================
--- mm-2.6.26-rc2-mm1.orig/mm/migrate.c
+++ mm-2.6.26-rc2-mm1/mm/migrate.c
@@ -360,7 +360,8 @@ static int migrate_page_move_mapping(str
write_unlock_irq(&mapping->tree_lock);
if (!PageSwapCache(newpage)) {
mem_cgroup_uncharge_cache_page(page);
- }
+ } else
+ mem_cgroup_uncharge_page(page);

return 0;
}
Index: mm-2.6.26-rc2-mm1/mm/swap_state.c
===================================================================
--- mm-2.6.26-rc2-mm1.orig/mm/swap_state.c
+++ mm-2.6.26-rc2-mm1/mm/swap_state.c
@@ -110,6 +110,7 @@ void __delete_from_swap_cache(struct pag
total_swapcache_pages--;
__dec_zone_page_state(page, NR_FILE_PAGES);
INC_CACHE_INFO(del_total);
+ mem_cgroup_uncharge_page(page);
}

/**
Index: mm-2.6.26-rc2-mm1/mm/memcontrol.c
===================================================================
--- mm-2.6.26-rc2-mm1.orig/mm/memcontrol.c
+++ mm-2.6.26-rc2-mm1/mm/memcontrol.c
@@ -44,10 +44,10 @@ static struct kmem_cache *page_cgroup_ca
*/
enum mem_cgroup_stat_index {
/*
- * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
+ * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss/swapcache.
*/
MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
- MEM_CGROUP_STAT_RSS, /* # of pages charged as rss */
+ MEM_CGROUP_STAT_RSS, /* # of pages charged as anon/swapcache */
MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */

@@ -697,7 +697,8 @@ __mem_cgroup_uncharge_common(struct page

if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
&& ((pc->flags & PAGE_CGROUP_FLAG_CACHE)
- || page_mapped(page)))
+ || page_mapped(page)
+ || PageSwapCache(page)))
goto unlock;

mz = page_cgroup_zoneinfo(pc);
@@ -904,7 +905,7 @@ static const struct mem_cgroup_stat_desc
u64 unit;
} mem_cgroup_stat_desc[] = {
[MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, },
- [MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
+ [MEM_CGROUP_STAT_RSS] = { "anon/swapcache", PAGE_SIZE, },
[MEM_CGROUP_STAT_PGPGIN_COUNT] = {"pgpgin", 1, },
[MEM_CGROUP_STAT_PGPGOUT_COUNT] = {"pgpgout", 1, },
};


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