[PATCH 4/8] memcg, mm: move mem_cgroup_select_victim_node into vmscan

Michal Hocko
2015-07-08T12:28:28Z

From: Michal Hocko <mhocko@suse.cz>

We currently have only one caller of mem_cgroup_select_victim_node which
is sitting in mm/vmscan.c and which is already wrapped by CONFIG_MEMCG
ifdef. Now that we have struct mem_cgroup visible outside of
mm/memcontrol.c we can move the function and its dependencies there.
This even shrinks the code size by few bytes:

text data bss dec hex filename
478509 65806 26384 570699 8b54b mm/built-in.o.before
478445 65806 26384 570635 8b50b mm/built-in.o.after

Signed-off-by: Michal Hocko <mhocko@suse.cz>
---
include/linux/memcontrol.h | 6 ++-
mm/memcontrol.c | 99 +---------------------------------------------
mm/vmscan.c | 96 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 101 insertions(+), 100 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 8818eee95f93..78e9d4ac57a1 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -354,11 +354,13 @@ static inline bool mem_cgroup_disabled(void)
/*
* For memory reclaim.
*/
-int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
-
void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
int nr_pages);

+unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
+ int nid,
+ unsigned int lru_mask);
+
static inline bool mem_cgroup_lruvec_online(struct lruvec *lruvec)
{
struct mem_cgroup_per_zone *mz;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 759ec413e72c..4f76ee67023b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -694,7 +694,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
__this_cpu_add(memcg->stat->nr_page_events, nr_pages);
}

-static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
+unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
int nid,
unsigned int lru_mask)
{
@@ -1352,103 +1352,6 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
mutex_unlock(&oom_lock);
}

-#if MAX_NUMNODES > 1
-
-/**
- * test_mem_cgroup_node_reclaimable
- * @memcg: 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 *memcg,
- int nid, bool noswap)
-{
- if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
- return true;
- if (noswap || !total_swap_pages)
- return false;
- if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
- return true;
- return false;
-
-}
-
-/*
- * Always updating the nodemask is not very good - even if we have an empty
- * list or the wrong list here, we can start from some node and traverse all
- * nodes based on the zonelist. So update the list loosely once per 10 secs.
- *
- */
-static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
-{
- int nid;
- /*
- * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
- * pagein/pageout changes since the last update.
- */
- if (!atomic_read(&memcg->numainfo_events))
- return;
- if (atomic_inc_return(&memcg->numainfo_updating) > 1)
- return;
-
- /* make a nodemask where this memcg uses memory from */
- memcg->scan_nodes = node_states[N_MEMORY];
-
- for_each_node_mask(nid, node_states[N_MEMORY]) {
-
- if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
- node_clear(nid, memcg->scan_nodes);
- }
-
- atomic_set(&memcg->numainfo_events, 0);
- atomic_set(&memcg->numainfo_updating, 0);
-}
-
-/*
- * Selecting a node where we start reclaim from. Because what we need is just
- * reducing usage counter, start from anywhere is O,K. Considering
- * memory reclaim from current node, there are pros. and cons.
- *
- * Freeing memory from current node means freeing memory from a node which
- * we'll use or we've used. So, it may make LRU bad. And if several threads
- * hit limits, it will see a contention on a node. But freeing from remote
- * node means more costs for memory reclaim because of memory latency.
- *
- * Now, we use round-robin. Better algorithm is welcomed.
- */
-int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
-{
- int node;
-
- mem_cgroup_may_update_nodemask(memcg);
- node = memcg->last_scanned_node;
-
- node = next_node(node, memcg->scan_nodes);
- if (node == MAX_NUMNODES)
- node = first_node(memcg->scan_nodes);
- /*
- * We call this when we hit limit, not when pages are added to LRU.
- * No LRU may hold pages because all pages are UNEVICTABLE or
- * memcg is too small and all pages are not on LRU. In that case,
- * we use curret node.
- */
- if (unlikely(node == MAX_NUMNODES))
- node = numa_node_id();
-
- memcg->last_scanned_node = node;
- return node;
-}
-#else
-int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
-{
- return 0;
-}
-#endif
-
static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
struct zone *zone,
gfp_t gfp_mask,
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 903ca5f53339..27eb9343888a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2923,6 +2923,102 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
return sc.nr_reclaimed;
}

+#if MAX_NUMNODES > 1
+
+/**
+ * test_mem_cgroup_node_reclaimable
+ * @memcg: 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 *memcg,
+ int nid, bool noswap)
+{
+ if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
+ return true;
+ if (noswap || !total_swap_pages)
+ return false;
+ if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
+ return true;
+ return false;
+
+}
+/*
+ * Always updating the nodemask is not very good - even if we have an empty
+ * list or the wrong list here, we can start from some node and traverse all
+ * nodes based on the zonelist. So update the list loosely once per 10 secs.
+ *
+ */
+static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
+{
+ int nid;
+ /*
+ * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
+ * pagein/pageout changes since the last update.
+ */
+ if (!atomic_read(&memcg->numainfo_events))
+ return;
+ if (atomic_inc_return(&memcg->numainfo_updating) > 1)
+ return;
+
+ /* make a nodemask where this memcg uses memory from */
+ memcg->scan_nodes = node_states[N_MEMORY];
+
+ for_each_node_mask(nid, node_states[N_MEMORY]) {
+
+ if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
+ node_clear(nid, memcg->scan_nodes);
+ }
+
+ atomic_set(&memcg->numainfo_events, 0);
+ atomic_set(&memcg->numainfo_updating, 0);
+}
+
+/*
+ * Selecting a node where we start reclaim from. Because what we need is just
+ * reducing usage counter, start from anywhere is O,K. Considering
+ * memory reclaim from current node, there are pros. and cons.
+ *
+ * Freeing memory from current node means freeing memory from a node which
+ * we'll use or we've used. So, it may make LRU bad. And if several threads
+ * hit limits, it will see a contention on a node. But freeing from remote
+ * node means more costs for memory reclaim because of memory latency.
+ *
+ * Now, we use round-robin. Better algorithm is welcomed.
+ */
+static int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
+{
+ int node;
+
+ mem_cgroup_may_update_nodemask(memcg);
+ node = memcg->last_scanned_node;
+
+ node = next_node(node, memcg->scan_nodes);
+ if (node == MAX_NUMNODES)
+ node = first_node(memcg->scan_nodes);
+ /*
+ * We call this when we hit limit, not when pages are added to LRU.
+ * No LRU may hold pages because all pages are UNEVICTABLE or
+ * memcg is too small and all pages are not on LRU. In that case,
+ * we use curret node.
+ */
+ if (unlikely(node == MAX_NUMNODES))
+ node = numa_node_id();
+
+ memcg->last_scanned_node = node;
+ return node;
+}
+#else
+static int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
+{
+ return 0;
+}
+#endif
+
unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
unsigned long nr_pages,
gfp_t gfp_mask,
--
2.1.4