[PATCH 12/27] mm, vmscan: Make shrink_node decisions more node-centric

From: Mel Gorman
Date: Tue Jun 21 2016 - 10:27:50 EST

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Earlier patches focused on having direct reclaim and kswapd use data that
is node-centric for reclaiming but shrink_node() itself still uses too much
zone information. This patch removes unnecessary zone-based information
with the most important decision being whether to continue reclaim or
not. Some memcg APIs are adjusted as a result even though memcg itself
still uses some zone information.

Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 9 +++----
include/linux/mmzone.h | 4 ++--
include/linux/swap.h | 2 +-
mm/memcontrol.c | 17 +++++++-------
mm/page_alloc.c | 2 +-
mm/vmscan.c | 58 ++++++++++++++++++++++++++--------------------
mm/workingset.c | 6 ++---
7 files changed, 54 insertions(+), 44 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index cda436c79d8c..a13328851fea 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -306,7 +306,8 @@ void mem_cgroup_uncharge_list(struct list_head *page_list);

void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);

-struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
+struct lruvec *mem_cgroup_lruvec(struct pglist_data *, struct zone *zone,
+ struct mem_cgroup *);
struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);

bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg);
@@ -573,10 +574,10 @@ static inline void mem_cgroup_migrate(struct page *old, struct page *new)
{
}

-static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
- struct mem_cgroup *memcg)
+static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
+ struct zone *zone, struct mem_cgroup *memcg)
{
- return zone_lruvec(zone);
+ return node_lruvec(pgdat);
}

static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 890d1858aa22..6991eded0ffd 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -737,9 +737,9 @@ static inline spinlock_t *zone_lru_lock(struct zone *zone)
return &zone->zone_pgdat->lru_lock;
}

-static inline struct lruvec *zone_lruvec(struct zone *zone)
+static inline struct lruvec *node_lruvec(struct pglist_data *pgdat)
{
- return &zone->zone_pgdat->lruvec;
+ return &pgdat->lruvec;
}

static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 916e2eddecd6..0ad616d7c381 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -316,7 +316,7 @@ extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
unsigned long nr_pages,
gfp_t gfp_mask,
bool may_swap);
-extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
+extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
gfp_t gfp_mask, bool noswap,
struct zone *zone,
unsigned long *nr_scanned);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 864a4e3a82c1..aac5fae56ea4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -944,22 +944,23 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
iter = mem_cgroup_iter(NULL, iter, NULL))

/**
- * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
+ * mem_cgroup_lruvec - get the lru list vector for a node or a memcg zone
+ * @node: node of the wanted lruvec
* @zone: zone of the wanted lruvec
* @memcg: memcg of the wanted lruvec
*
- * Returns the lru list vector holding pages for the given @zone and
- * @mem. This can be the global zone lruvec, if the memory controller
+ * 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.
*/
-struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
- struct mem_cgroup *memcg)
+struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
+ struct zone *zone, struct mem_cgroup *memcg)
{
struct mem_cgroup_per_zone *mz;
struct lruvec *lruvec;

if (mem_cgroup_disabled()) {
- lruvec = zone_lruvec(zone);
+ lruvec = node_lruvec(pgdat);
goto out;
}

@@ -1474,8 +1475,8 @@ static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
}
continue;
}
- total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
- zone, &nr_scanned);
+ total += mem_cgroup_shrink_node(victim, gfp_mask, false,
+ zone, &nr_scanned);
*total_scanned += nr_scanned;
if (!soft_limit_excess(root_memcg))
break;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e128af8de05f..d62b147fd426 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5897,6 +5897,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
#endif
pgdat_page_ext_init(pgdat);
spin_lock_init(&pgdat->lru_lock);
+ lruvec_init(node_lruvec(pgdat));

for (j = 0; j < MAX_NR_ZONES; j++) {
struct zone *zone = pgdat->node_zones + j;
@@ -5959,7 +5960,6 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
/* For bootup, initialized properly in watermark setup */
mod_zone_page_state(zone, NR_ALLOC_BATCH, zone->managed_pages);

- lruvec_init(zone_lruvec(zone));
if (!size)
continue;

diff --git a/mm/vmscan.c b/mm/vmscan.c
index d42a86e603e8..3774ebf19f63 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2220,10 +2220,11 @@ static inline void init_tlb_ubc(void)
/*
* This is a basic per-zone page freer. Used by both kswapd and direct reclaim.
*/
-static void shrink_zone_memcg(struct zone *zone, struct mem_cgroup *memcg,
+static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memcg,
struct scan_control *sc, unsigned long *lru_pages)
{
- struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+ struct zone *zone = &pgdat->node_zones[sc->reclaim_idx];
+ struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, zone, memcg);
unsigned long nr[NR_LRU_LISTS];
unsigned long targets[NR_LRU_LISTS];
unsigned long nr_to_scan;
@@ -2356,13 +2357,14 @@ static bool in_reclaim_compaction(struct scan_control *sc)
* calls try_to_compact_zone() that it will have enough free pages to succeed.
* It will give up earlier than that if there is difficulty reclaiming pages.
*/
-static inline bool should_continue_reclaim(struct zone *zone,
+static inline bool should_continue_reclaim(struct pglist_data *pgdat,
unsigned long nr_reclaimed,
unsigned long nr_scanned,
struct scan_control *sc)
{
unsigned long pages_for_compaction;
unsigned long inactive_lru_pages;
+ int z;

/* If not in reclaim/compaction mode, stop */
if (!in_reclaim_compaction(sc))
@@ -2396,21 +2398,27 @@ static inline bool should_continue_reclaim(struct zone *zone,
* inactive lists are large enough, continue reclaiming
*/
pages_for_compaction = (2UL << sc->order);
- inactive_lru_pages = node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE);
+ inactive_lru_pages = node_page_state(pgdat, NR_INACTIVE_FILE);
if (get_nr_swap_pages() > 0)
- inactive_lru_pages += node_page_state(zone->zone_pgdat, NR_INACTIVE_ANON);
+ inactive_lru_pages += node_page_state(pgdat, NR_INACTIVE_ANON);
if (sc->nr_reclaimed < pages_for_compaction &&
inactive_lru_pages > pages_for_compaction)
return true;

/* If compaction would go ahead or the allocation would succeed, stop */
- switch (compaction_suitable(zone, sc->order, 0, 0)) {
- case COMPACT_PARTIAL:
- case COMPACT_CONTINUE:
- return false;
- default:
- return true;
+ for (z = 0; z <= sc->reclaim_idx; z++) {
+ struct zone *zone = &pgdat->node_zones[z];
+
+ switch (compaction_suitable(zone, sc->order, 0, sc->reclaim_idx)) {
+ case COMPACT_PARTIAL:
+ case COMPACT_CONTINUE:
+ return false;
+ default:
+ /* check next zone */
+ ;
+ }
}
+ return true;
}

static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
@@ -2419,15 +2427,14 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
struct reclaim_state *reclaim_state = current->reclaim_state;
unsigned long nr_reclaimed, nr_scanned;
bool reclaimable = false;
- struct zone *zone = &pgdat->node_zones[classzone_idx];

do {
struct mem_cgroup *root = sc->target_mem_cgroup;
struct mem_cgroup_reclaim_cookie reclaim = {
- .zone = zone,
+ .zone = &pgdat->node_zones[classzone_idx],
.priority = sc->priority,
};
- unsigned long zone_lru_pages = 0;
+ unsigned long node_lru_pages = 0;
struct mem_cgroup *memcg;

nr_reclaimed = sc->nr_reclaimed;
@@ -2448,11 +2455,11 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
reclaimed = sc->nr_reclaimed;
scanned = sc->nr_scanned;

- shrink_zone_memcg(zone, memcg, sc, &lru_pages);
- zone_lru_pages += lru_pages;
+ shrink_node_memcg(pgdat, memcg, sc, &lru_pages);
+ node_lru_pages += lru_pages;

if (!global_reclaim(sc) && sc->reclaim_idx == classzone_idx)
- shrink_slab(sc->gfp_mask, zone_to_nid(zone),
+ shrink_slab(sc->gfp_mask, pgdat->node_id,
memcg, sc->nr_scanned - scanned,
lru_pages);

@@ -2464,7 +2471,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
/*
* Direct reclaim and kswapd have to scan all memory
* cgroups to fulfill the overall scan target for the
- * zone.
+ * node.
*
* Limit reclaim, on the other hand, only cares about
* nr_to_reclaim pages to be reclaimed and it will
@@ -2483,9 +2490,9 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
* the eligible LRU pages were scanned.
*/
if (global_reclaim(sc) && sc->reclaim_idx == classzone_idx)
- shrink_slab(sc->gfp_mask, zone_to_nid(zone), NULL,
+ shrink_slab(sc->gfp_mask, pgdat->node_id, NULL,
sc->nr_scanned - nr_scanned,
- zone_lru_pages);
+ node_lru_pages);

if (reclaim_state) {
sc->nr_reclaimed += reclaim_state->reclaimed_slab;
@@ -2500,7 +2507,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
if (sc->nr_reclaimed - nr_reclaimed)
reclaimable = true;

- } while (should_continue_reclaim(zone, sc->nr_reclaimed - nr_reclaimed,
+ } while (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,
sc->nr_scanned - nr_scanned, sc));

return reclaimable;
@@ -2896,7 +2903,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,

#ifdef CONFIG_MEMCG

-unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
+unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
gfp_t gfp_mask, bool noswap,
struct zone *zone,
unsigned long *nr_scanned)
@@ -2906,6 +2913,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
.target_mem_cgroup = memcg,
.may_writepage = !laptop_mode,
.may_unmap = 1,
+ .reclaim_idx = zone_idx(zone),
.may_swap = !noswap,
};
unsigned long lru_pages;
@@ -2920,11 +2928,11 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
/*
* NOTE: Although we can get the priority field, using it
* here is not a good idea, since it limits the pages we can scan.
- * if we don't reclaim here, the shrink_zone from balance_pgdat
+ * if we don't reclaim here, the shrink_node from balance_pgdat
* will pick up pages from other mem cgroup's as well. We hack
* the priority and make it zero.
*/
- shrink_zone_memcg(zone, memcg, &sc, &lru_pages);
+ shrink_node_memcg(zone->zone_pgdat, memcg, &sc, &lru_pages);

trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);

@@ -2982,7 +2990,7 @@ static void age_active_anon(struct pglist_data *pgdat,

memcg = mem_cgroup_iter(NULL, NULL, NULL);
do {
- struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+ struct lruvec *lruvec = mem_cgroup_lruvec(pgdat, zone, memcg);

if (inactive_list_is_low(lruvec, false))
shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
diff --git a/mm/workingset.c b/mm/workingset.c
index c0820e06aaff..2d81ca11317d 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -218,7 +218,7 @@ void *workingset_eviction(struct address_space *mapping, struct page *page)
VM_BUG_ON_PAGE(page_count(page), page);
VM_BUG_ON_PAGE(!PageLocked(page), page);

- lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+ lruvec = mem_cgroup_lruvec(zone->zone_pgdat, zone, memcg);
eviction = atomic_long_inc_return(&lruvec->inactive_age);
return pack_shadow(memcgid, zone, eviction);
}
@@ -267,7 +267,7 @@ bool workingset_refault(void *shadow)
rcu_read_unlock();
return false;
}
- lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+ lruvec = mem_cgroup_lruvec(zone->zone_pgdat, zone, memcg);
refault = atomic_long_read(&lruvec->inactive_age);
active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE);
rcu_read_unlock();
@@ -317,7 +317,7 @@ void workingset_activation(struct page *page)
*/
if (!mem_cgroup_disabled() && !page_memcg(page))
goto out;
- lruvec = mem_cgroup_zone_lruvec(page_zone(page), page_memcg(page));
+ lruvec = mem_cgroup_lruvec(page_pgdat(page), page_zone(page), page_memcg(page));
atomic_long_inc(&lruvec->inactive_age);
out:
unlock_page_memcg(page);
--
2.6.4

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