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Commit 4d0c066d authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
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memcg: fix reclaimable lru check in memcg 



Now, in mem_cgroup_hierarchical_reclaim(), mem_cgroup_local_usage() is
used for checking whether the memcg contains reclaimable pages or not.  If
no pages in it, the routine skips it.

But, mem_cgroup_local_usage() contains Unevictable pages and cannot handle
"noswap" condition correctly.  This doesn't work on a swapless system.

This patch adds test_mem_cgroup_reclaimable() and replaces
mem_cgroup_local_usage().  test_mem_cgroup_reclaimable() see LRU counter
and returns correct answer to the caller.  And this new function has
"noswap" argument and can see only FILE LRU if necessary.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix kerneldoc layout]
Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0b43c3aa

mm/memcontrol.c

+76 −31
Original line number Diff line number Diff line
@@ -577,15 +577,6 @@ static long mem_cgroup_read_stat(struct mem_cgroup *mem, 
	return val;

}



static long mem_cgroup_local_usage(struct mem_cgroup *mem)

{

	long ret;



	ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);

	ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);

	return ret;

}



static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,

					 bool charge)

{
@@ -1129,7 +1120,6 @@ unsigned long mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, 
	return MEM_CGROUP_ZSTAT(mz, lru);

}



#ifdef CONFIG_NUMA

static unsigned long mem_cgroup_node_nr_file_lru_pages(struct mem_cgroup *memcg,

							int nid)

{
@@ -1141,6 +1131,17 @@ static unsigned long mem_cgroup_node_nr_file_lru_pages(struct mem_cgroup *memcg, 
	return ret;

}



static unsigned long mem_cgroup_node_nr_anon_lru_pages(struct mem_cgroup *memcg,

							int nid)

{

	unsigned long ret;



	ret = mem_cgroup_get_zonestat_node(memcg, nid, LRU_INACTIVE_ANON) +

		mem_cgroup_get_zonestat_node(memcg, nid, LRU_ACTIVE_ANON);

	return ret;

}



#if MAX_NUMNODES > 1

static unsigned long mem_cgroup_nr_file_lru_pages(struct mem_cgroup *memcg)

{

	u64 total = 0;
@@ -1152,17 +1153,6 @@ static unsigned long mem_cgroup_nr_file_lru_pages(struct mem_cgroup *memcg) 
	return total;

}



static unsigned long mem_cgroup_node_nr_anon_lru_pages(struct mem_cgroup *memcg,

							int nid)

{

	unsigned long ret;



	ret = mem_cgroup_get_zonestat_node(memcg, nid, LRU_INACTIVE_ANON) +

		mem_cgroup_get_zonestat_node(memcg, nid, LRU_ACTIVE_ANON);



	return ret;

}



static unsigned long mem_cgroup_nr_anon_lru_pages(struct mem_cgroup *memcg)

{

	u64 total = 0;
@@ -1559,6 +1549,28 @@ mem_cgroup_select_victim(struct mem_cgroup *root_mem) 
	return ret;

}



/**

 * test_mem_cgroup_node_reclaimable

 * @mem: the target memcg

 * @nid: the node ID to be checked.

 * @noswap : specify true here if the user wants flle only information.

 *

 * This function returns whether the specified memcg contains any

 * reclaimable pages on a node. Returns true if there are any reclaimable

 * pages in the node.

 */

static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *mem,

		int nid, bool noswap)

{

	if (mem_cgroup_node_nr_file_lru_pages(mem, nid))

		return true;

	if (noswap || !total_swap_pages)

		return false;

	if (mem_cgroup_node_nr_anon_lru_pages(mem, nid))

		return true;

	return false;



}

#if MAX_NUMNODES > 1



/*
@@ -1580,14 +1592,7 @@ static void mem_cgroup_may_update_nodemask(struct mem_cgroup *mem) 


	for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {



		if (mem_cgroup_get_zonestat_node(mem, nid, LRU_INACTIVE_FILE) ||

		    mem_cgroup_get_zonestat_node(mem, nid, LRU_ACTIVE_FILE))

			continue;



		if (total_swap_pages &&

		    (mem_cgroup_get_zonestat_node(mem, nid, LRU_INACTIVE_ANON) ||

		     mem_cgroup_get_zonestat_node(mem, nid, LRU_ACTIVE_ANON)))

			continue;

		if (!test_mem_cgroup_node_reclaimable(mem, nid, false))

			node_clear(nid, mem->scan_nodes);

	}

}
@@ -1627,11 +1632,51 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *mem) 
	return node;

}



/*

 * Check all nodes whether it contains reclaimable pages or not.

 * For quick scan, we make use of scan_nodes. This will allow us to skip

 * unused nodes. But scan_nodes is lazily updated and may not cotain

 * enough new information. We need to do double check.

 */

bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)

{

	int nid;



	/*

	 * quick check...making use of scan_node.

	 * We can skip unused nodes.

	 */

	if (!nodes_empty(mem->scan_nodes)) {

		for (nid = first_node(mem->scan_nodes);

		     nid < MAX_NUMNODES;

		     nid = next_node(nid, mem->scan_nodes)) {



			if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))

				return true;

		}

	}

	/*

	 * Check rest of nodes.

	 */

	for_each_node_state(nid, N_HIGH_MEMORY) {

		if (node_isset(nid, mem->scan_nodes))

			continue;

		if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))

			return true;

	}

	return false;

}



#else

int mem_cgroup_select_victim_node(struct mem_cgroup *mem)

{

	return 0;

}



bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)

{

	return test_mem_cgroup_node_reclaimable(mem, 0, noswap);

}

#endif



/*
@@ -1702,7 +1747,7 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, 
				}

			}

		}

		if (!mem_cgroup_local_usage(victim)) {

		if (!mem_cgroup_reclaimable(victim, noswap)) {

			/* this cgroup's local usage == 0 */

			css_put(&victim->css);

			continue;