summaryrefslogtreecommitdiffstats
path: root/mm/vmscan.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c88
1 files changed, 62 insertions, 26 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index eca70310adb2..093f5fe6dd77 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -36,6 +36,7 @@
#include <linux/rwsem.h>
#include <linux/delay.h>
#include <linux/kthread.h>
+#include <linux/freezer.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -378,6 +379,12 @@ static pageout_t pageout(struct page *page, struct address_space *mapping)
return PAGE_CLEAN;
}
+/*
+ * Attempt to detach a locked page from its ->mapping. If it is dirty or if
+ * someone else has a ref on the page, abort and return 0. If it was
+ * successfully detached, return 1. Assumes the caller has a single ref on
+ * this page.
+ */
int remove_mapping(struct address_space *mapping, struct page *page)
{
BUG_ON(!PageLocked(page));
@@ -717,6 +724,20 @@ done:
return nr_reclaimed;
}
+/*
+ * We are about to scan this zone at a certain priority level. If that priority
+ * level is smaller (ie: more urgent) than the previous priority, then note
+ * that priority level within the zone. This is done so that when the next
+ * process comes in to scan this zone, it will immediately start out at this
+ * priority level rather than having to build up its own scanning priority.
+ * Here, this priority affects only the reclaim-mapped threshold.
+ */
+static inline void note_zone_scanning_priority(struct zone *zone, int priority)
+{
+ if (priority < zone->prev_priority)
+ zone->prev_priority = priority;
+}
+
static inline int zone_is_near_oom(struct zone *zone)
{
return zone->pages_scanned >= (zone->nr_active + zone->nr_inactive)*3;
@@ -740,7 +761,7 @@ static inline int zone_is_near_oom(struct zone *zone)
* But we had to alter page->flags anyway.
*/
static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
- struct scan_control *sc)
+ struct scan_control *sc, int priority)
{
unsigned long pgmoved;
int pgdeactivate = 0;
@@ -764,7 +785,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
* `distress' is a measure of how much trouble we're having
* reclaiming pages. 0 -> no problems. 100 -> great trouble.
*/
- distress = 100 >> zone->prev_priority;
+ distress = 100 >> min(zone->prev_priority, priority);
/*
* The point of this algorithm is to decide when to start
@@ -916,7 +937,7 @@ static unsigned long shrink_zone(int priority, struct zone *zone,
nr_to_scan = min(nr_active,
(unsigned long)sc->swap_cluster_max);
nr_active -= nr_to_scan;
- shrink_active_list(nr_to_scan, zone, sc);
+ shrink_active_list(nr_to_scan, zone, sc, priority);
}
if (nr_inactive) {
@@ -966,9 +987,7 @@ static unsigned long shrink_zones(int priority, struct zone **zones,
if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
continue;
- zone->temp_priority = priority;
- if (zone->prev_priority > priority)
- zone->prev_priority = priority;
+ note_zone_scanning_priority(zone, priority);
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
@@ -1018,7 +1037,6 @@ unsigned long try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
continue;
- zone->temp_priority = DEF_PRIORITY;
lru_pages += zone->nr_active + zone->nr_inactive;
}
@@ -1053,19 +1071,28 @@ unsigned long try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
/* Take a nap, wait for some writeback to complete */
if (sc.nr_scanned && priority < DEF_PRIORITY - 2)
- blk_congestion_wait(WRITE, HZ/10);
+ congestion_wait(WRITE, HZ/10);
}
/* top priority shrink_caches still had more to do? don't OOM, then */
if (!sc.all_unreclaimable)
ret = 1;
out:
+ /*
+ * Now that we've scanned all the zones at this priority level, note
+ * that level within the zone so that the next thread which performs
+ * scanning of this zone will immediately start out at this priority
+ * level. This affects only the decision whether or not to bring
+ * mapped pages onto the inactive list.
+ */
+ if (priority < 0)
+ priority = 0;
for (i = 0; zones[i] != 0; i++) {
struct zone *zone = zones[i];
if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
continue;
- zone->prev_priority = zone->temp_priority;
+ zone->prev_priority = priority;
}
return ret;
}
@@ -1105,6 +1132,11 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
.swap_cluster_max = SWAP_CLUSTER_MAX,
.swappiness = vm_swappiness,
};
+ /*
+ * temp_priority is used to remember the scanning priority at which
+ * this zone was successfully refilled to free_pages == pages_high.
+ */
+ int temp_priority[MAX_NR_ZONES];
loop_again:
total_scanned = 0;
@@ -1112,11 +1144,8 @@ loop_again:
sc.may_writepage = !laptop_mode;
count_vm_event(PAGEOUTRUN);
- for (i = 0; i < pgdat->nr_zones; i++) {
- struct zone *zone = pgdat->node_zones + i;
-
- zone->temp_priority = DEF_PRIORITY;
- }
+ for (i = 0; i < pgdat->nr_zones; i++)
+ temp_priority[i] = DEF_PRIORITY;
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */
@@ -1144,11 +1173,12 @@ loop_again:
if (!zone_watermark_ok(zone, order, zone->pages_high,
0, 0)) {
end_zone = i;
- goto scan;
+ break;
}
}
- goto out;
-scan:
+ if (i < 0)
+ goto out;
+
for (i = 0; i <= end_zone; i++) {
struct zone *zone = pgdat->node_zones + i;
@@ -1177,10 +1207,9 @@ scan:
if (!zone_watermark_ok(zone, order, zone->pages_high,
end_zone, 0))
all_zones_ok = 0;
- zone->temp_priority = priority;
- if (zone->prev_priority > priority)
- zone->prev_priority = priority;
+ temp_priority[i] = priority;
sc.nr_scanned = 0;
+ note_zone_scanning_priority(zone, priority);
nr_reclaimed += shrink_zone(priority, zone, &sc);
reclaim_state->reclaimed_slab = 0;
nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
@@ -1208,7 +1237,7 @@ scan:
* another pass across the zones.
*/
if (total_scanned && priority < DEF_PRIORITY - 2)
- blk_congestion_wait(WRITE, HZ/10);
+ congestion_wait(WRITE, HZ/10);
/*
* We do this so kswapd doesn't build up large priorities for
@@ -1220,13 +1249,21 @@ scan:
break;
}
out:
+ /*
+ * Note within each zone the priority level at which this zone was
+ * brought into a happy state. So that the next thread which scans this
+ * zone will start out at that priority level.
+ */
for (i = 0; i < pgdat->nr_zones; i++) {
struct zone *zone = pgdat->node_zones + i;
- zone->prev_priority = zone->temp_priority;
+ zone->prev_priority = temp_priority[i];
}
if (!all_zones_ok) {
cond_resched();
+
+ try_to_freeze();
+
goto loop_again;
}
@@ -1352,7 +1389,7 @@ static unsigned long shrink_all_zones(unsigned long nr_pages, int pass,
if (zone->nr_scan_active >= nr_pages || pass > 3) {
zone->nr_scan_active = 0;
nr_to_scan = min(nr_pages, zone->nr_active);
- shrink_active_list(nr_to_scan, zone, sc);
+ shrink_active_list(nr_to_scan, zone, sc, prio);
}
}
@@ -1452,7 +1489,7 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
goto out;
if (sc.nr_scanned && prio < DEF_PRIORITY - 2)
- blk_congestion_wait(WRITE, HZ / 10);
+ congestion_wait(WRITE, HZ / 10);
}
lru_pages = 0;
@@ -1476,7 +1513,6 @@ out:
}
#endif
-#ifdef CONFIG_HOTPLUG_CPU
/* It's optimal to keep kswapds on the same CPUs as their memory, but
not required for correctness. So if the last cpu in a node goes
away, we get changed to run anywhere: as the first one comes back,
@@ -1497,7 +1533,6 @@ static int __devinit cpu_callback(struct notifier_block *nfb,
}
return NOTIFY_OK;
}
-#endif /* CONFIG_HOTPLUG_CPU */
/*
* This kswapd start function will be called by init and node-hot-add.
@@ -1608,6 +1643,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
*/
priority = ZONE_RECLAIM_PRIORITY;
do {
+ note_zone_scanning_priority(zone, priority);
nr_reclaimed += shrink_zone(priority, zone, &sc);
priority--;
} while (priority >= 0 && nr_reclaimed < nr_pages);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-26 22:29:13 +0000