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Commit 11c9ea4e authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

memcg: convert per-cpu stock from bytes to page granularity 



We never keep subpage quantities in the per-cpu stock.

Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e7018b8d

mm/memcontrol.c

+13 −11
Original line number Diff line number Diff line
@@ -1650,14 +1650,14 @@ EXPORT_SYMBOL(mem_cgroup_update_page_stat); 
#define CHARGE_SIZE	(32 * PAGE_SIZE)

struct memcg_stock_pcp {

	struct mem_cgroup *cached; /* this never be root cgroup */

	int charge;

	unsigned int nr_pages;

	struct work_struct work;

};

static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);

static atomic_t memcg_drain_count;



/*

 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed

 * Try to consume stocked charge on this cpu. If success, one page is consumed

 * from local stock and true is returned. If the stock is 0 or charges from a

 * cgroup which is not current target, returns false. This stock will be

 * refilled.
@@ -1668,8 +1668,8 @@ static bool consume_stock(struct mem_cgroup *mem) 
	bool ret = true;



	stock = &get_cpu_var(memcg_stock);

	if (mem == stock->cached && stock->charge)

		stock->charge -= PAGE_SIZE;

	if (mem == stock->cached && stock->nr_pages)

		stock->nr_pages--;

	else /* need to call res_counter_charge */

		ret = false;

	put_cpu_var(memcg_stock);
@@ -1683,13 +1683,15 @@ static void drain_stock(struct memcg_stock_pcp *stock) 
{

	struct mem_cgroup *old = stock->cached;



	if (stock->charge) {

		res_counter_uncharge(&old->res, stock->charge);

	if (stock->nr_pages) {

		unsigned long bytes = stock->nr_pages * PAGE_SIZE;



		res_counter_uncharge(&old->res, bytes);

		if (do_swap_account)

			res_counter_uncharge(&old->memsw, stock->charge);

			res_counter_uncharge(&old->memsw, bytes);

		stock->nr_pages = 0;

	}

	stock->cached = NULL;

	stock->charge = 0;

}



/*
@@ -1706,7 +1708,7 @@ static void drain_local_stock(struct work_struct *dummy) 
 * Cache charges(val) which is from res_counter, to local per_cpu area.

 * This will be consumed by consume_stock() function, later.

 */

static void refill_stock(struct mem_cgroup *mem, int val)

static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages)

{

	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
@@ -1714,7 +1716,7 @@ static void refill_stock(struct mem_cgroup *mem, int val) 
		drain_stock(stock);

		stock->cached = mem;

	}

	stock->charge += val;

	stock->nr_pages += nr_pages;

	put_cpu_var(memcg_stock);

}
@@ -2012,7 +2014,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, 
	} while (ret != CHARGE_OK);



	if (csize > page_size)

		refill_stock(mem, csize - page_size);

		refill_stock(mem, (csize - page_size) >> PAGE_SHIFT);

	css_put(&mem->css);

done:

	*memcg = mem;