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mm: memcg: move pc lookup point to commit_charge()

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None of the callsites actually need the page_cgroup descriptor
themselves, so just pass the page and do the look up in there.

We already had two bugs (6568d4a 'mm: memcg: update the correct soft
limit tree during migration' and 'memcg: fix Bad page state after
replace_page_cache') where the passed page and pc were not referring
to the same page frame.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner 2012-04-24 20:22:33 +02:00 committed by Linus Torvalds
parent 4e1c2b2844
commit ce587e65e8
1 changed files with 5 additions and 12 deletions
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17
mm/memcontrol.c
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@ -2476,10 +2476,10 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
struct page *page, struct page *page,
unsigned int nr_pages, unsigned int nr_pages,
struct page_cgroup *pc,
enum charge_type ctype, enum charge_type ctype,
bool lrucare) bool lrucare)
{ {
struct page_cgroup *pc = lookup_page_cgroup(page);
struct zone *uninitialized_var(zone); struct zone *uninitialized_var(zone);
bool was_on_lru = false; bool was_on_lru = false;
bool anon; bool anon;
@ -2716,7 +2716,6 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
{ {
struct mem_cgroup *memcg = NULL; struct mem_cgroup *memcg = NULL;
unsigned int nr_pages = 1; unsigned int nr_pages = 1;
struct page_cgroup *pc;
bool oom = true; bool oom = true;
int ret; int ret;
@ -2730,11 +2729,10 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
oom = false; oom = false;
} }
pc = lookup_page_cgroup(page);
ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom); ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom);
if (ret == -ENOMEM) if (ret == -ENOMEM)
return ret; return ret;
__mem_cgroup_commit_charge(memcg, page, nr_pages, pc, ctype, false); __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false);
return 0; return 0;
} }
@ -2831,16 +2829,13 @@ static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg, __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
enum charge_type ctype) enum charge_type ctype)
{ {
struct page_cgroup *pc;
if (mem_cgroup_disabled()) if (mem_cgroup_disabled())
return; return;
if (!memcg) if (!memcg)
return; return;
cgroup_exclude_rmdir(&memcg->css); cgroup_exclude_rmdir(&memcg->css);
pc = lookup_page_cgroup(page); __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
__mem_cgroup_commit_charge(memcg, page, 1, pc, ctype, true);
/* /*
* Now swap is on-memory. This means this page may be * Now swap is on-memory. This means this page may be
* counted both as mem and swap....double count. * counted both as mem and swap....double count.
@ -3298,14 +3293,13 @@ int mem_cgroup_prepare_migration(struct page *page,
* page. In the case new page is migrated but not remapped, new page's * page. In the case new page is migrated but not remapped, new page's
* mapcount will be finally 0 and we call uncharge in end_migration(). * mapcount will be finally 0 and we call uncharge in end_migration().
*/ */
pc = lookup_page_cgroup(newpage);
if (PageAnon(page)) if (PageAnon(page))
ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
else if (page_is_file_cache(page)) else if (page_is_file_cache(page))
ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
else else
ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
__mem_cgroup_commit_charge(memcg, newpage, 1, pc, ctype, false); __mem_cgroup_commit_charge(memcg, newpage, 1, ctype, false);
return ret; return ret;
} }
@ -3392,8 +3386,7 @@ void mem_cgroup_replace_page_cache(struct page *oldpage,
* the newpage may be on LRU(or pagevec for LRU) already. We lock * the newpage may be on LRU(or pagevec for LRU) already. We lock
* LRU while we overwrite pc->mem_cgroup. * LRU while we overwrite pc->mem_cgroup.
*/ */
pc = lookup_page_cgroup(newpage); __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
__mem_cgroup_commit_charge(memcg, newpage, 1, pc, type, true);
} }
#ifdef CONFIG_DEBUG_VM #ifdef CONFIG_DEBUG_VM