1 files changed, 73 insertions, 25 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index db76ef7..da53a25 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -612,8 +612,10 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
 	/* pagein of a big page is an event. So, ignore page size */
 	if (nr_pages > 0)
 		__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
-	else
+	else {
 		__this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
+		nr_pages = -nr_pages; /* for event */
+	}
 
 	__this_cpu_add(mem->stat->count[MEM_CGROUP_EVENTS], nr_pages);
 
@@ -1111,6 +1113,23 @@ static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
 	return false;
 }
 
+/**
+ * mem_cgroup_check_margin - check if the memory cgroup allows charging
+ * @mem: memory cgroup to check
+ * @bytes: the number of bytes the caller intends to charge
+ *
+ * Returns a boolean value on whether @mem can be charged @bytes or
+ * whether this would exceed the limit.
+ */
+static bool mem_cgroup_check_margin(struct mem_cgroup *mem, unsigned long bytes)
+{
+	if (!res_counter_check_margin(&mem->res, bytes))
+		return false;
+	if (do_swap_account && !res_counter_check_margin(&mem->memsw, bytes))
+		return false;
+	return true;
+}
+
 static unsigned int get_swappiness(struct mem_cgroup *memcg)
 {
 	struct cgroup *cgrp = memcg->css.cgroup;
@@ -1832,27 +1851,39 @@ static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask,
 		if (likely(!ret))
 			return CHARGE_OK;
 
+		res_counter_uncharge(&mem->res, csize);
 		mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
 		flags |= MEM_CGROUP_RECLAIM_NOSWAP;
 	} else
 		mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
-
-	if (csize > PAGE_SIZE) /* change csize and retry */
+	/*
+	 * csize can be either a huge page (HPAGE_SIZE), a batch of
+	 * regular pages (CHARGE_SIZE), or a single regular page
+	 * (PAGE_SIZE).
+	 *
+	 * Never reclaim on behalf of optional batching, retry with a
+	 * single page instead.
+	 */
+	if (csize == CHARGE_SIZE)
 		return CHARGE_RETRY;
 
 	if (!(gfp_mask & __GFP_WAIT))
 		return CHARGE_WOULDBLOCK;
 
 	ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
-					gfp_mask, flags);
+					      gfp_mask, flags);
+	if (mem_cgroup_check_margin(mem_over_limit, csize))
+		return CHARGE_RETRY;
 	/*
-	 * try_to_free_mem_cgroup_pages() might not give us a full
-	 * picture of reclaim. Some pages are reclaimed and might be
-	 * moved to swap cache or just unmapped from the cgroup.
-	 * Check the limit again to see if the reclaim reduced the
-	 * current usage of the cgroup before giving up
+	 * Even though the limit is exceeded at this point, reclaim
+	 * may have been able to free some pages.  Retry the charge
+	 * before killing the task.
+	 *
+	 * Only for regular pages, though: huge pages are rather
+	 * unlikely to succeed so close to the limit, and we fall back
+	 * to regular pages anyway in case of failure.
 	 */
-	if (ret || mem_cgroup_check_under_limit(mem_over_limit))
+	if (csize == PAGE_SIZE && ret)
 		return CHARGE_RETRY;
 
 	/*
@@ -2144,6 +2175,8 @@ void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
 	struct page_cgroup *tail_pc = lookup_page_cgroup(tail);
 	unsigned long flags;
 
+	if (mem_cgroup_disabled())
+		return;
 	/*
 	 * We have no races with charge/uncharge but will have races with
 	 * page state accounting.
@@ -2233,7 +2266,12 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
 {
 	int ret = -EINVAL;
 	unsigned long flags;
-
+	/*
+	 * The page is isolated from LRU. So, collapse function
+	 * will not handle this page. But page splitting can happen.
+	 * Do this check under compound_page_lock(). The caller should
+	 * hold it.
+	 */
 	if ((charge_size > PAGE_SIZE) && !PageTransHuge(pc->page))
 		return -EBUSY;
 
@@ -2265,7 +2303,7 @@ 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;
+	int page_size = PAGE_SIZE;
 	unsigned long flags;
 	int ret;
 
@@ -2278,23 +2316,26 @@ 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);
+
+	if (PageTransHuge(page))
+		page_size = HPAGE_SIZE;
 
 	parent = mem_cgroup_from_cont(pcg);
-	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, charge);
+	ret = __mem_cgroup_try_charge(NULL, gfp_mask,
+				&parent, false, page_size);
 	if (ret || !parent)
 		goto put_back;
 
-	if (charge > PAGE_SIZE)
+	if (page_size > PAGE_SIZE)
 		flags = compound_lock_irqsave(page);
 
-	ret = mem_cgroup_move_account(pc, child, parent, true, charge);
+	ret = mem_cgroup_move_account(pc, child, parent, true, page_size);
 	if (ret)
-		mem_cgroup_cancel_charge(parent, charge);
-put_back:
-	if (charge > PAGE_SIZE)
+		mem_cgroup_cancel_charge(parent, page_size);
+
+	if (page_size > PAGE_SIZE)
 		compound_unlock_irqrestore(page, flags);
+put_back:
 	putback_lru_page(page);
 put:
 	put_page(page);
@@ -2312,13 +2353,19 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
 				gfp_t gfp_mask, enum charge_type ctype)
 {
 	struct mem_cgroup *mem = NULL;
+	int page_size = PAGE_SIZE;
 	struct page_cgroup *pc;
+	bool oom = true;
 	int ret;
-	int page_size = PAGE_SIZE;
 
 	if (PageTransHuge(page)) {
 		page_size <<= compound_order(page);
 		VM_BUG_ON(!PageTransHuge(page));
+		/*
+		 * Never OOM-kill a process for a huge page.  The
+		 * fault handler will fall back to regular pages.
+		 */
+		oom = false;
 	}
 
 	pc = lookup_page_cgroup(page);
@@ -2327,7 +2374,7 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
 		return 0;
 	prefetchw(pc);
 
-	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true, page_size);
+	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size);
 	if (ret || !mem)
 		return ret;
 
@@ -5013,9 +5060,9 @@ struct cgroup_subsys mem_cgroup_subsys = {
 static int __init enable_swap_account(char *s)
 {
 	/* consider enabled if no parameter or 1 is given */
-	if (!s || !strcmp(s, "1"))
+	if (!(*s) || !strcmp(s, "=1"))
 		really_do_swap_account = 1;
-	else if (!strcmp(s, "0"))
+	else if (!strcmp(s, "=0"))
 		really_do_swap_account = 0;
 	return 1;
 }
@@ -5023,7 +5070,8 @@ __setup("swapaccount", enable_swap_account);
 
 static int __init disable_swap_account(char *s)
 {
-	enable_swap_account("0");
+	printk_once("noswapaccount is deprecated and will be removed in 2.6.40. Use swapaccount=0 instead\n");
+	enable_swap_account("=0");
 	return 1;
 }
 __setup("noswapaccount", disable_swap_account);