* removed from global LRU.
*/
mz = page_cgroup_zoneinfo(pc);
- MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+ /* huge page split is done under lru_lock. so, we have no races. */
+ MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
if (mem_cgroup_is_root(pc->mem_cgroup))
return;
VM_BUG_ON(list_empty(&pc->lru));
return;
pc = lookup_page_cgroup(page);
- /*
- * Used bit is set without atomic ops but after smp_wmb().
- * For making pc->mem_cgroup visible, insert smp_rmb() here.
- */
- smp_rmb();
/* unused or root page is not rotated. */
- if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
+ if (!PageCgroupUsed(pc))
+ return;
+ /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
+ smp_rmb();
+ if (mem_cgroup_is_root(pc->mem_cgroup))
return;
mz = page_cgroup_zoneinfo(pc);
list_move(&pc->lru, &mz->lists[lru]);
return;
pc = lookup_page_cgroup(page);
VM_BUG_ON(PageCgroupAcctLRU(pc));
- /*
- * Used bit is set without atomic ops but after smp_wmb().
- * For making pc->mem_cgroup visible, insert smp_rmb() here.
- */
- smp_rmb();
if (!PageCgroupUsed(pc))
return;
-
+ /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
+ smp_rmb();
mz = page_cgroup_zoneinfo(pc);
- MEM_CGROUP_ZSTAT(mz, lru) += 1;
+ /* huge page split is done under lru_lock. so, we have no races. */
+ MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
SetPageCgroupAcctLRU(pc);
if (mem_cgroup_is_root(pc->mem_cgroup))
return;
return NULL;
pc = lookup_page_cgroup(page);
- /*
- * Used bit is set without atomic ops but after smp_wmb().
- * For making pc->mem_cgroup visible, insert smp_rmb() here.
- */
- smp_rmb();
if (!PageCgroupUsed(pc))
return NULL;
-
+ /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
+ smp_rmb();
mz = page_cgroup_zoneinfo(pc);
if (!mz)
return NULL;
if (unlikely(!mem || !PageCgroupUsed(pc)))
goto out;
/* pc->mem_cgroup is unstable ? */
- if (unlikely(mem_cgroup_stealed(mem))) {
+ if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) {
/* take a lock against to access pc->mem_cgroup */
move_lock_page_cgroup(pc, &flags);
need_unlock = true;
return mem;
}
-/*
- * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
- * USED state. If already USED, uncharge and return.
- */
-static void ____mem_cgroup_commit_charge(struct mem_cgroup *mem,
- struct page_cgroup *pc,
- enum charge_type ctype)
+static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
+ struct page_cgroup *pc,
+ enum charge_type ctype,
+ int page_size)
{
+ int nr_pages = page_size >> PAGE_SHIFT;
+
+ /* try_charge() can return NULL to *memcg, taking care of it. */
+ if (!mem)
+ return;
+
+ lock_page_cgroup(pc);
+ if (unlikely(PageCgroupUsed(pc))) {
+ unlock_page_cgroup(pc);
+ mem_cgroup_cancel_charge(mem, page_size);
+ return;
+ }
+ /*
+ * we don't need page_cgroup_lock about tail pages, becase they are not
+ * accessed by any other context at this point.
+ */
pc->mem_cgroup = mem;
/*
* We access a page_cgroup asynchronously without lock_page_cgroup().
break;
}
- mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), 1);
-}
-
-static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
- struct page_cgroup *pc,
- enum charge_type ctype,
- int page_size)
-{
- int i;
- int count = page_size >> PAGE_SHIFT;
-
- /* try_charge() can return NULL to *memcg, taking care of it. */
- if (!mem)
- return;
-
- lock_page_cgroup(pc);
- if (unlikely(PageCgroupUsed(pc))) {
- unlock_page_cgroup(pc);
- mem_cgroup_cancel_charge(mem, page_size);
- return;
- }
-
- /*
- * we don't need page_cgroup_lock about tail pages, becase they are not
- * accessed by any other context at this point.
- */
- for (i = 0; i < count; i++)
- ____mem_cgroup_commit_charge(mem, pc + i, ctype);
-
+ mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages);
unlock_page_cgroup(pc);
/*
* "charge_statistics" updated event counter. Then, check it.
memcg_check_events(mem, pc->page);
}
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
+#define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\
+ (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION))
+/*
+ * Because tail pages are not marked as "used", set it. We're under
+ * zone->lru_lock, 'splitting on pmd' and compund_lock.
+ */
+void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
+{
+ struct page_cgroup *head_pc = lookup_page_cgroup(head);
+ struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
+ unsigned long flags;
+
+ /*
+ * We have no races with charge/uncharge but will have races with
+ * page state accounting.
+ */
+ move_lock_page_cgroup(head_pc, &flags);
+
+ tail_pc->mem_cgroup = head_pc->mem_cgroup;
+ smp_wmb(); /* see __commit_charge() */
+ if (PageCgroupAcctLRU(head_pc)) {
+ enum lru_list lru;
+ struct mem_cgroup_per_zone *mz;
+
+ /*
+ * LRU flags cannot be copied because we need to add tail
+ *.page to LRU by generic call and our hook will be called.
+ * We hold lru_lock, then, reduce counter directly.
+ */
+ lru = page_lru(head);
+ mz = page_cgroup_zoneinfo(head_pc);
+ MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+ }
+ tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
+ move_unlock_page_cgroup(head_pc, &flags);
+}
+#endif
+
/**
* __mem_cgroup_move_account - move account of the page
* @pc: page_cgroup of the page.
*/
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));
__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
* __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;
}
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 ? */
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);
static struct mem_cgroup *
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
{
- int i;
int count;
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
break;
}
- for (i = 0; i < count; i++)
- mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -1);
+ mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -count);
ClearPageCgroupUsed(pc);
/*
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++;