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memcg: fix rmdir, force_empty with THP

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Now, when THP is enabled, memcg's rmdir() function is broken because
move_account() for THP page is not supported.

This will cause account leak or -EBUSY issue at rmdir().
This patch fixes the issue by supporting move_account() THP pages.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki 2011-01-20 14:44:25 -08:00 committed by Linus Torvalds
parent ece35ca810
commit 987eba66e0
1 changed files with 26 additions and 11 deletions
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37
mm/memcontrol.c
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@ -2197,8 +2197,11 @@ void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
*/
static void __mem_cgroup_move_account(struct page_cgroup *pc,
struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge,
int charge_size)
{
int nr_pages = charge_size >> PAGE_SHIFT;
VM_BUG_ON(from == to);
VM_BUG_ON(PageLRU(pc->page));
VM_BUG_ON(!page_is_cgroup_locked(pc));
@ -2212,14 +2215,14 @@ static void __mem_cgroup_move_account(struct page_cgroup *pc,
__this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
preempt_enable();
}
mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -1);
mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
if (uncharge)
/* This is not "cancel", but cancel_charge does all we need. */
mem_cgroup_cancel_charge(from, PAGE_SIZE);
mem_cgroup_cancel_charge(from, charge_size);
/* caller should have done css_get */
pc->mem_cgroup = to;
mem_cgroup_charge_statistics(to, PageCgroupCache(pc), 1);
mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages);
/*
* We charges against "to" which may not have any tasks. Then, "to"
* can be under rmdir(). But in current implementation, caller of
@ -2234,15 +2237,19 @@ static void __mem_cgroup_move_account(struct page_cgroup *pc,
* __mem_cgroup_move_account()
*/
static int mem_cgroup_move_account(struct page_cgroup *pc,
struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge)
struct mem_cgroup *from, struct mem_cgroup *to,
bool uncharge, int charge_size)
{
int ret = -EINVAL;
unsigned long flags;
if ((charge_size > PAGE_SIZE) && !PageTransHuge(pc->page))
return -EBUSY;
lock_page_cgroup(pc);
if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
move_lock_page_cgroup(pc, &flags);
__mem_cgroup_move_account(pc, from, to, uncharge);
__mem_cgroup_move_account(pc, from, to, uncharge, charge_size);
move_unlock_page_cgroup(pc, &flags);
ret = 0;
}
@ -2267,6 +2274,8 @@ static int mem_cgroup_move_parent(struct page_cgroup *pc,
struct cgroup *cg = child->css.cgroup;
struct cgroup *pcg = cg->parent;
struct mem_cgroup *parent;
int charge = PAGE_SIZE;
unsigned long flags;
int ret;
/* Is ROOT ? */
@ -2278,17 +2287,23 @@ static int mem_cgroup_move_parent(struct page_cgroup *pc,
goto out;
if (isolate_lru_page(page))
goto put;
/* The page is isolated from LRU and we have no race with splitting */
charge = PAGE_SIZE << compound_order(page);
parent = mem_cgroup_from_cont(pcg);
ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false,
PAGE_SIZE);
ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, charge);
if (ret || !parent)
goto put_back;
ret = mem_cgroup_move_account(pc, child, parent, true);
if (charge > PAGE_SIZE)
flags = compound_lock_irqsave(page);
ret = mem_cgroup_move_account(pc, child, parent, true, charge);
if (ret)
mem_cgroup_cancel_charge(parent, PAGE_SIZE);
mem_cgroup_cancel_charge(parent, charge);
put_back:
if (charge > PAGE_SIZE)
compound_unlock_irqrestore(page, flags);
putback_lru_page(page);
put:
put_page(page);
@ -4868,7 +4883,7 @@ retry:
goto put;
pc = lookup_page_cgroup(page);
if (!mem_cgroup_move_account(pc,
mc.from, mc.to, false)) {
mc.from, mc.to, false, PAGE_SIZE)) {
mc.precharge--;
/* we uncharge from mc.from later. */
mc.moved_charge++;