There is a per-memcg lruvec and a NUMA node lruvec. Which one is being
used is somewhat confusing right now, and it's easy to make mistakes -
especially when it comes to global reclaim.
How it works: when memory cgroups are enabled, we always use the
root_mem_cgroup's per-node lruvecs. When memory cgroups are not
compiled in or disabled at runtime, we use pgdat->lruvec.
Document that in a comment.
Due to the way the reclaim code is generalized, all lookups use the
mem_cgroup_lruvec() helper function, and nobody should have to find
the right lruvec manually right now. But to avoid future mistakes,
rename the pgdat->lruvec member to pgdat->__lruvec and delete the
convenience wrapper that suggests it's a commonly accessed member.
While in this area, swap the mem_cgroup_lruvec() argument order. The
name suggests a memcg operation, yet it takes a pgdat first and a
memcg second. I have to double take every time I call this. Fix that.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
include/linux/memcontrol.h | 26 +++++++++++++-------------
include/linux/mmzone.h | 15 ++++++++-------
mm/memcontrol.c | 6 +++---
mm/page_alloc.c | 2 +-
mm/vmscan.c | 6 +++---
mm/workingset.c | 8 ++++----
6 files changed, 32 insertions(+), 31 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index fa1e8cb1b3e2..fc32cfaebf32 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -382,22 +382,22 @@ mem_cgroup_nodeinfo(struct mem_cgroup *memcg, int nid)
}
/**
- * mem_cgroup_lruvec - get the lru list vector for a node or a memcg zone
- * @node: node of the wanted lruvec
+ * mem_cgroup_lruvec - get the lru list vector for a memcg & node
* @memcg: memcg of the wanted lruvec
+ * @node: node of the wanted lruvec
*
- * Returns the lru list vector holding pages for a given @node or a given
- * @memcg and @zone. This can be the node lruvec, if the memory controller
- * is disabled.
+ * Returns the lru list vector holding pages for a given @memcg &
+ * @node combination. This can be the node lruvec, if the memory
+ * controller is disabled.
*/
-static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
- struct mem_cgroup *memcg)
+static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
+ struct pglist_data *pgdat)
{
struct mem_cgroup_per_node *mz;
struct lruvec *lruvec;
if (mem_cgroup_disabled()) {
- lruvec = node_lruvec(pgdat);
+ lruvec = &pgdat->__lruvec;
goto out;
}
@@ -716,7 +716,7 @@ static inline void __mod_lruvec_page_state(struct page *page,
return;
}
- lruvec = mem_cgroup_lruvec(pgdat, page->mem_cgroup);
+ lruvec = mem_cgroup_lruvec(page->mem_cgroup, pgdat);
__mod_lruvec_state(lruvec, idx, val);
}
@@ -887,16 +887,16 @@ static inline void mem_cgroup_migrate(struct page *old, struct page *new)
{
}
-static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
- struct mem_cgroup *memcg)
+static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
+ struct pglist_data *pgdat)
{
- return node_lruvec(pgdat);
+ return &pgdat->__lruvec;
}
static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
struct pglist_data *pgdat)
{
- return &pgdat->lruvec;
+ return &pgdat->__lruvec;
}
static inline bool mm_match_cgroup(struct mm_struct *mm,
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 427b79c39b3c..95d63a395f40 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -761,7 +761,13 @@ typedef struct pglist_data {
#endif
/* Fields commonly accessed by the page reclaim scanner */
- struct lruvec lruvec;
+
+ /*
+ * NOTE: THIS IS UNUSED IF MEMCG IS ENABLED.
+ *
+ * Use mem_cgroup_lruvec() to look up lruvecs.
+ */
+ struct lruvec __lruvec;
unsigned long flags;
@@ -784,11 +790,6 @@ typedef struct pglist_data {
#define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn)
#define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
-static inline struct lruvec *node_lruvec(struct pglist_data *pgdat)
-{
- return &pgdat->lruvec;
-}
-
static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
{
return pgdat->node_start_pfn + pgdat->node_spanned_pages;
@@ -826,7 +827,7 @@ static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec)
#ifdef CONFIG_MEMCG
return lruvec->pgdat;
#else
- return container_of(lruvec, struct pglist_data, lruvec);
+ return container_of(lruvec, struct pglist_data, __lruvec);
#endif
}
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c193aef3ba9e..6de8ca735ee2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1200,7 +1200,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
struct lruvec *lruvec;
if (mem_cgroup_disabled()) {
- lruvec = &pgdat->lruvec;
+ lruvec = &pgdat->__lruvec;
goto out;
}
@@ -1518,7 +1518,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
int nid, bool noswap)
{
- struct lruvec *lruvec = mem_cgroup_lruvec(NODE_DATA(nid), memcg);
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
if (lruvec_page_state(lruvec, NR_INACTIVE_FILE) ||
lruvec_page_state(lruvec, NR_ACTIVE_FILE))
@@ -3406,7 +3406,7 @@ static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
int nid, unsigned int lru_mask)
{
- struct lruvec *lruvec = mem_cgroup_lruvec(NODE_DATA(nid), memcg);
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
unsigned long nr = 0;
enum lru_list lru;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a345418b548e..cd8e64e536f7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6619,7 +6619,7 @@ static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
pgdat_page_ext_init(pgdat);
spin_lock_init(&pgdat->lru_lock);
- lruvec_init(node_lruvec(pgdat));
+ lruvec_init(&pgdat->__lruvec);
}
static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f396424850aa..853be16ee5e2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2477,7 +2477,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memcg,
struct scan_control *sc)
{
- struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, memcg);
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
unsigned long nr[NR_LRU_LISTS];
unsigned long targets[NR_LRU_LISTS];
unsigned long nr_to_scan;
@@ -2988,7 +2988,7 @@ static void snapshot_refaults(struct mem_cgroup *root_memcg, pg_data_t *pgdat)
unsigned long refaults;
struct lruvec *lruvec;
- lruvec = mem_cgroup_lruvec(pgdat, memcg);
+ lruvec = mem_cgroup_lruvec(memcg, pgdat);
refaults = lruvec_page_state_local(lruvec, WORKINGSET_ACTIVATE);
lruvec->refaults = refaults;
} while ((memcg = mem_cgroup_iter(root_memcg, memcg, NULL)));
@@ -3351,7 +3351,7 @@ static void age_active_anon(struct pglist_data *pgdat,
memcg = mem_cgroup_iter(NULL, NULL, NULL);
do {
- struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, memcg);
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
if (inactive_list_is_low(lruvec, false, sc, true))
shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
diff --git a/mm/workingset.c b/mm/workingset.c
index e0b4edcb88c8..2aaa70bea99c 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -233,7 +233,7 @@ void *workingset_eviction(struct page *page)
VM_BUG_ON_PAGE(page_count(page), page);
VM_BUG_ON_PAGE(!PageLocked(page), page);
- lruvec = mem_cgroup_lruvec(pgdat, memcg);
+ lruvec = mem_cgroup_lruvec(memcg, pgdat);
eviction = atomic_long_inc_return(&lruvec->inactive_age);
return pack_shadow(memcgid, pgdat, eviction, PageWorkingset(page));
}
@@ -280,7 +280,7 @@ void workingset_refault(struct page *page, void *shadow)
memcg = mem_cgroup_from_id(memcgid);
if (!mem_cgroup_disabled() && !memcg)
goto out;
- lruvec = mem_cgroup_lruvec(pgdat, memcg);
+ lruvec = mem_cgroup_lruvec(memcg, pgdat);
refault = atomic_long_read(&lruvec->inactive_age);
active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES);
@@ -345,7 +345,7 @@ void workingset_activation(struct page *page)
memcg = page_memcg_rcu(page);
if (!mem_cgroup_disabled() && !memcg)
goto out;
- lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg);
+ lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
atomic_long_inc(&lruvec->inactive_age);
out:
rcu_read_unlock();
@@ -428,7 +428,7 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
struct lruvec *lruvec;
int i;
- lruvec = mem_cgroup_lruvec(NODE_DATA(sc->nid), sc->memcg);
+ lruvec = mem_cgroup_lruvec(sc->memcg, NODE_DATA(sc->nid));
for (pages = 0, i = 0; i < NR_LRU_LISTS; i++)
pages += lruvec_page_state_local(lruvec,
NR_LRU_BASE + i);
--
2.21.0
