[PATCH 4.9 047/153] mm, vmscan: cleanup lru size claculations

Greg Kroah-Hartman
2017-03-10T11:25:46Z

From: Michal Hocko <mhocko@suse.com>

commit fd538803731e50367b7c59ce4ad3454426a3d671 upstream.

lruvec_lru_size returns the full size of the LRU list while we sometimes
need a value reduced only to eligible zones (e.g. for lowmem requests).
inactive_list_is_low is one such user. Later patches will add more of
them. Add a new parameter to lruvec_lru_size and allow it filter out
zones which are not eligible for the given context.

Link: http://lkml.kernel.org/r/20170117103702.28542-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/mmzone.h | 2 -
mm/vmscan.c | 81 +++++++++++++++++++++++--------------------------
mm/workingset.c | 2 -
3 files changed, 41 insertions(+), 44 deletions(-)

--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -779,7 +779,7 @@ static inline struct pglist_data *lruvec
#endif
}

-extern unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru);
+extern unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone_idx);

#ifdef CONFIG_HAVE_MEMORY_PRESENT
void memory_present(int nid, unsigned long start, unsigned long end);
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -234,22 +234,39 @@ bool pgdat_reclaimable(struct pglist_dat
pgdat_reclaimable_pages(pgdat) * 6;
}

-unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru)
+/**
+ * lruvec_lru_size - Returns the number of pages on the given LRU list.
+ * @lruvec: lru vector
+ * @lru: lru to use
+ * @zone_idx: zones to consider (use MAX_NR_ZONES for the whole LRU list)
+ */
+unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone_idx)
{
+ unsigned long lru_size;
+ int zid;
+
if (!mem_cgroup_disabled())
- return mem_cgroup_get_lru_size(lruvec, lru);
+ lru_size = mem_cgroup_get_lru_size(lruvec, lru);
+ else
+ lru_size = node_page_state(lruvec_pgdat(lruvec), NR_LRU_BASE + lru);

- return node_page_state(lruvec_pgdat(lruvec), NR_LRU_BASE + lru);
-}
+ for (zid = zone_idx + 1; zid < MAX_NR_ZONES; zid++) {
+ struct zone *zone = &lruvec_pgdat(lruvec)->node_zones[zid];
+ unsigned long size;

-unsigned long lruvec_zone_lru_size(struct lruvec *lruvec, enum lru_list lru,
- int zone_idx)
-{
- if (!mem_cgroup_disabled())
- return mem_cgroup_get_zone_lru_size(lruvec, lru, zone_idx);
+ if (!managed_zone(zone))
+ continue;
+
+ if (!mem_cgroup_disabled())
+ size = mem_cgroup_get_zone_lru_size(lruvec, lru, zid);
+ else
+ size = zone_page_state(&lruvec_pgdat(lruvec)->node_zones[zid],
+ NR_ZONE_LRU_BASE + lru);
+ lru_size -= min(size, lru_size);
+ }
+
+ return lru_size;

- return zone_page_state(&lruvec_pgdat(lruvec)->node_zones[zone_idx],
- NR_ZONE_LRU_BASE + lru);
}

/*
@@ -2028,11 +2045,10 @@ static bool inactive_list_is_low(struct
struct scan_control *sc)
{
unsigned long inactive_ratio;
- unsigned long inactive;
- unsigned long active;
+ unsigned long inactive, active;
+ enum lru_list inactive_lru = file * LRU_FILE;
+ enum lru_list active_lru = file * LRU_FILE + LRU_ACTIVE;
unsigned long gb;
- struct pglist_data *pgdat = lruvec_pgdat(lruvec);
- int zid;

/*
* If we don't have swap space, anonymous page deactivation
@@ -2041,27 +2057,8 @@ static bool inactive_list_is_low(struct
if (!file && !total_swap_pages)
return false;

- inactive = lruvec_lru_size(lruvec, file * LRU_FILE);
- active = lruvec_lru_size(lruvec, file * LRU_FILE + LRU_ACTIVE);
-
- /*
- * For zone-constrained allocations, it is necessary to check if
- * deactivations are required for lowmem to be reclaimed. This
- * calculates the inactive/active pages available in eligible zones.
- */
- for (zid = sc->reclaim_idx + 1; zid < MAX_NR_ZONES; zid++) {
- struct zone *zone = &pgdat->node_zones[zid];
- unsigned long inactive_zone, active_zone;
-
- if (!managed_zone(zone))
- continue;
-
- inactive_zone = lruvec_zone_lru_size(lruvec, file * LRU_FILE, zid);
- active_zone = lruvec_zone_lru_size(lruvec, (file * LRU_FILE) + LRU_ACTIVE, zid);
-
- inactive -= min(inactive, inactive_zone);
- active -= min(active, active_zone);
- }
+ inactive = lruvec_lru_size(lruvec, inactive_lru, sc->reclaim_idx);
+ active = lruvec_lru_size(lruvec, active_lru, sc->reclaim_idx);

gb = (inactive + active) >> (30 - PAGE_SHIFT);
if (gb)
@@ -2208,7 +2205,7 @@ static void get_scan_count(struct lruvec
* system is under heavy pressure.
*/
if (!inactive_list_is_low(lruvec, true, sc) &&
- lruvec_lru_size(lruvec, LRU_INACTIVE_FILE) >> sc->priority) {
+ lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, MAX_NR_ZONES) >> sc->priority) {
scan_balance = SCAN_FILE;
goto out;
}
@@ -2234,10 +2231,10 @@ static void get_scan_count(struct lruvec
* anon in [0], file in [1]
*/

- anon = lruvec_lru_size(lruvec, LRU_ACTIVE_ANON) +
- lruvec_lru_size(lruvec, LRU_INACTIVE_ANON);
- file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE) +
- lruvec_lru_size(lruvec, LRU_INACTIVE_FILE);
+ anon = lruvec_lru_size(lruvec, LRU_ACTIVE_ANON, MAX_NR_ZONES) +
+ lruvec_lru_size(lruvec, LRU_INACTIVE_ANON, MAX_NR_ZONES);
+ file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES) +
+ lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, MAX_NR_ZONES);

spin_lock_irq(&pgdat->lru_lock);
if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
@@ -2275,7 +2272,7 @@ out:
unsigned long size;
unsigned long scan;

- size = lruvec_lru_size(lruvec, lru);
+ size = lruvec_lru_size(lruvec, lru, MAX_NR_ZONES);
scan = size >> sc->priority;

if (!scan && pass && force_scan)
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -266,7 +266,7 @@ bool workingset_refault(void *shadow)
}
lruvec = mem_cgroup_lruvec(pgdat, memcg);
refault = atomic_long_read(&lruvec->inactive_age);
- active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE);
+ active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES);
rcu_read_unlock();

/*