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-rw-r--r--mm/vmscan.c109
1 files changed, 68 insertions, 41 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index faa0a088f9cc..d036e59d302b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1124,8 +1124,20 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
nr_lumpy_dirty++;
scan++;
} else {
- /* the page is freed already. */
- if (!page_count(cursor_page))
+ /*
+ * Check if the page is freed already.
+ *
+ * We can't use page_count() as that
+ * requires compound_head and we don't
+ * have a pin on the page here. If a
+ * page is tail, we may or may not
+ * have isolated the head, so assume
+ * it's not free, it'd be tricky to
+ * track the head status without a
+ * page pin.
+ */
+ if (!PageTail(cursor_page) &&
+ !atomic_read(&cursor_page->_count))
continue;
break;
}
@@ -1983,14 +1995,13 @@ restart:
* If a zone is deemed to be full of pinned pages then just give it a light
* scan then give up on it.
*/
-static unsigned long shrink_zones(int priority, struct zonelist *zonelist,
+static void shrink_zones(int priority, struct zonelist *zonelist,
struct scan_control *sc)
{
struct zoneref *z;
struct zone *zone;
unsigned long nr_soft_reclaimed;
unsigned long nr_soft_scanned;
- unsigned long total_scanned = 0;
for_each_zone_zonelist_nodemask(zone, z, zonelist,
gfp_zone(sc->gfp_mask), sc->nodemask) {
@@ -2005,19 +2016,23 @@ static unsigned long shrink_zones(int priority, struct zonelist *zonelist,
continue;
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
+ /*
+ * This steals pages from memory cgroups over softlimit
+ * and returns the number of reclaimed pages and
+ * scanned pages. This works for global memory pressure
+ * and balancing, not for a memcg's limit.
+ */
+ nr_soft_scanned = 0;
+ nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone,
+ sc->order, sc->gfp_mask,
+ &nr_soft_scanned);
+ sc->nr_reclaimed += nr_soft_reclaimed;
+ sc->nr_scanned += nr_soft_scanned;
+ /* need some check for avoid more shrink_zone() */
}
- nr_soft_scanned = 0;
- nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone,
- sc->order, sc->gfp_mask,
- &nr_soft_scanned);
- sc->nr_reclaimed += nr_soft_reclaimed;
- total_scanned += nr_soft_scanned;
-
shrink_zone(priority, zone, sc);
}
-
- return total_scanned;
}
static bool zone_reclaimable(struct zone *zone)
@@ -2081,8 +2096,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
sc->nr_scanned = 0;
if (!priority)
- disable_swap_token();
- total_scanned += shrink_zones(priority, zonelist, sc);
+ disable_swap_token(sc->mem_cgroup);
+ shrink_zones(priority, zonelist, sc);
/*
* Don't shrink slabs when reclaiming memory from
* over limit cgroups
@@ -2295,7 +2310,8 @@ static bool pgdat_balanced(pg_data_t *pgdat, unsigned long balanced_pages,
for (i = 0; i <= classzone_idx; i++)
present_pages += pgdat->node_zones[i].present_pages;
- return balanced_pages > (present_pages >> 2);
+ /* A special case here: if zone has no page, we think it's balanced */
+ return balanced_pages >= (present_pages >> 2);
}
/* is kswapd sleeping prematurely? */
@@ -2311,7 +2327,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
return true;
/* Check the watermark levels */
- for (i = 0; i < pgdat->nr_zones; i++) {
+ for (i = 0; i <= classzone_idx; i++) {
struct zone *zone = pgdat->node_zones + i;
if (!populated_zone(zone))
@@ -2329,7 +2345,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
}
if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone),
- classzone_idx, 0))
+ i, 0))
all_zones_ok = false;
else
balanced += zone->present_pages;
@@ -2407,7 +2423,7 @@ loop_again:
/* The swap token gets in the way of swapout... */
if (!priority)
- disable_swap_token();
+ disable_swap_token(NULL);
all_zones_ok = 1;
balanced = 0;
@@ -2436,7 +2452,6 @@ loop_again:
if (!zone_watermark_ok_safe(zone, order,
high_wmark_pages(zone), 0, 0)) {
end_zone = i;
- *classzone_idx = i;
break;
}
}
@@ -2495,18 +2510,18 @@ loop_again:
KSWAPD_ZONE_BALANCE_GAP_RATIO);
if (!zone_watermark_ok_safe(zone, order,
high_wmark_pages(zone) + balance_gap,
- end_zone, 0))
+ end_zone, 0)) {
shrink_zone(priority, zone, &sc);
- reclaim_state->reclaimed_slab = 0;
- nr_slab = shrink_slab(&shrink, sc.nr_scanned, lru_pages);
- sc.nr_reclaimed += reclaim_state->reclaimed_slab;
- total_scanned += sc.nr_scanned;
- if (zone->all_unreclaimable)
- continue;
- if (nr_slab == 0 &&
- !zone_reclaimable(zone))
- zone->all_unreclaimable = 1;
+ reclaim_state->reclaimed_slab = 0;
+ nr_slab = shrink_slab(&shrink, sc.nr_scanned, lru_pages);
+ sc.nr_reclaimed += reclaim_state->reclaimed_slab;
+ total_scanned += sc.nr_scanned;
+
+ if (nr_slab == 0 && !zone_reclaimable(zone))
+ zone->all_unreclaimable = 1;
+ }
+
/*
* If we've done a decent amount of scanning and
* the reclaim ratio is low, start doing writepage
@@ -2516,6 +2531,12 @@ loop_again:
total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2)
sc.may_writepage = 1;
+ if (zone->all_unreclaimable) {
+ if (end_zone && end_zone == i)
+ end_zone--;
+ continue;
+ }
+
if (!zone_watermark_ok_safe(zone, order,
high_wmark_pages(zone), end_zone, 0)) {
all_zones_ok = 0;
@@ -2694,8 +2715,8 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
*/
static int kswapd(void *p)
{
- unsigned long order;
- int classzone_idx;
+ unsigned long order, new_order;
+ int classzone_idx, new_classzone_idx;
pg_data_t *pgdat = (pg_data_t*)p;
struct task_struct *tsk = current;
@@ -2725,17 +2746,23 @@ static int kswapd(void *p)
tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
set_freezable();
- order = 0;
- classzone_idx = MAX_NR_ZONES - 1;
+ order = new_order = 0;
+ classzone_idx = new_classzone_idx = pgdat->nr_zones - 1;
for ( ; ; ) {
- unsigned long new_order;
- int new_classzone_idx;
int ret;
- new_order = pgdat->kswapd_max_order;
- new_classzone_idx = pgdat->classzone_idx;
- pgdat->kswapd_max_order = 0;
- pgdat->classzone_idx = MAX_NR_ZONES - 1;
+ /*
+ * If the last balance_pgdat was unsuccessful it's unlikely a
+ * new request of a similar or harder type will succeed soon
+ * so consider going to sleep on the basis we reclaimed at
+ */
+ if (classzone_idx >= new_classzone_idx && order == new_order) {
+ new_order = pgdat->kswapd_max_order;
+ new_classzone_idx = pgdat->classzone_idx;
+ pgdat->kswapd_max_order = 0;
+ pgdat->classzone_idx = pgdat->nr_zones - 1;
+ }
+
if (order < new_order || classzone_idx > new_classzone_idx) {
/*
* Don't sleep if someone wants a larger 'order'
@@ -2748,7 +2775,7 @@ static int kswapd(void *p)
order = pgdat->kswapd_max_order;
classzone_idx = pgdat->classzone_idx;
pgdat->kswapd_max_order = 0;
- pgdat->classzone_idx = MAX_NR_ZONES - 1;
+ pgdat->classzone_idx = pgdat->nr_zones - 1;
}
ret = try_to_freeze();
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-23 19:47:47 +0300