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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2008-02-07 00:14:37 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-07 08:42:22 -0800
commit1cfb419b394ba82745c54ff05436d598ecc2dbd5 (patch)
tree33624176aff8f3a09f572c0fa3d699dbacdb447d /mm/vmscan.c
parentper-zone and reclaim enhancements for memory controller: calculate the number of pages to be scanned per cgroup (diff)
downloadlinux-dev-1cfb419b394ba82745c54ff05436d598ecc2dbd5.tar.xz
linux-dev-1cfb419b394ba82745c54ff05436d598ecc2dbd5.zip
per-zone and reclaim enhancements for memory controller: modifies vmscan.c for isolate globa/cgroup lru activity
When using memory controller, there are 2 levels of memory reclaim. 1. zone memory reclaim because of system/zone memory shortage. 2. memory cgroup memory reclaim because of hitting limit. These two can be distinguished by sc->mem_cgroup parameter. (scan_global_lru() macro) This patch tries to make memory cgroup reclaim routine avoid affecting system/zone memory reclaim. This patch inserts if (scan_global_lru()) and hook to memory_cgroup reclaim support functions. This patch can be a help for isolating system lru activity and group lru activity and shows what additional functions are necessary. * mem_cgroup_calc_mapped_ratio() ... calculate mapped ratio for cgroup. * mem_cgroup_reclaim_imbalance() ... calculate active/inactive balance in cgroup. * mem_cgroup_calc_reclaim_active() ... calculate the number of active pages to be scanned in this priority in mem_cgroup. * mem_cgroup_calc_reclaim_inactive() ... calculate the number of inactive pages to be scanned in this priority in mem_cgroup. * mem_cgroup_all_unreclaimable() .. checks cgroup's page is all unreclaimable or not. * mem_cgroup_get_reclaim_priority() ... * mem_cgroup_note_reclaim_priority() ... record reclaim priority (temporal) * mem_cgroup_remember_reclaim_priority() .... record reclaim priority as zone->prev_priority. This value is used for calc reclaim_mapped. [akpm@linux-foundation.org: fix unused var warning] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--mm/vmscan.c332
1 files changed, 201 insertions, 131 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index be4dfe87be03..a26dabd62fed 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -856,7 +856,8 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
__mod_zone_page_state(zone, NR_ACTIVE, -nr_active);
__mod_zone_page_state(zone, NR_INACTIVE,
-(nr_taken - nr_active));
- zone->pages_scanned += nr_scan;
+ if (scan_global_lru(sc))
+ zone->pages_scanned += nr_scan;
spin_unlock_irq(&zone->lru_lock);
nr_scanned += nr_scan;
@@ -888,8 +889,9 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
if (current_is_kswapd()) {
__count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scan);
__count_vm_events(KSWAPD_STEAL, nr_freed);
- } else
+ } else if (scan_global_lru(sc))
__count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scan);
+
__count_zone_vm_events(PGSTEAL, zone, nr_freed);
if (nr_taken == 0)
@@ -943,6 +945,113 @@ static inline int zone_is_near_oom(struct zone *zone)
}
/*
+ * Determine we should try to reclaim mapped pages.
+ * This is called only when sc->mem_cgroup is NULL.
+ */
+static int calc_reclaim_mapped(struct scan_control *sc, struct zone *zone,
+ int priority)
+{
+ long mapped_ratio;
+ long distress;
+ long swap_tendency;
+ long imbalance;
+ int reclaim_mapped = 0;
+ int prev_priority;
+
+ if (scan_global_lru(sc) && zone_is_near_oom(zone))
+ return 1;
+ /*
+ * `distress' is a measure of how much trouble we're having
+ * reclaiming pages. 0 -> no problems. 100 -> great trouble.
+ */
+ if (scan_global_lru(sc))
+ prev_priority = zone->prev_priority;
+ else
+ prev_priority = mem_cgroup_get_reclaim_priority(sc->mem_cgroup);
+
+ distress = 100 >> min(prev_priority, priority);
+
+ /*
+ * The point of this algorithm is to decide when to start
+ * reclaiming mapped memory instead of just pagecache. Work out
+ * how much memory
+ * is mapped.
+ */
+ if (scan_global_lru(sc))
+ mapped_ratio = ((global_page_state(NR_FILE_MAPPED) +
+ global_page_state(NR_ANON_PAGES)) * 100) /
+ vm_total_pages;
+ else
+ mapped_ratio = mem_cgroup_calc_mapped_ratio(sc->mem_cgroup);
+
+ /*
+ * Now decide how much we really want to unmap some pages. The
+ * mapped ratio is downgraded - just because there's a lot of
+ * mapped memory doesn't necessarily mean that page reclaim
+ * isn't succeeding.
+ *
+ * The distress ratio is important - we don't want to start
+ * going oom.
+ *
+ * A 100% value of vm_swappiness overrides this algorithm
+ * altogether.
+ */
+ swap_tendency = mapped_ratio / 2 + distress + sc->swappiness;
+
+ /*
+ * If there's huge imbalance between active and inactive
+ * (think active 100 times larger than inactive) we should
+ * become more permissive, or the system will take too much
+ * cpu before it start swapping during memory pressure.
+ * Distress is about avoiding early-oom, this is about
+ * making swappiness graceful despite setting it to low
+ * values.
+ *
+ * Avoid div by zero with nr_inactive+1, and max resulting
+ * value is vm_total_pages.
+ */
+ if (scan_global_lru(sc)) {
+ imbalance = zone_page_state(zone, NR_ACTIVE);
+ imbalance /= zone_page_state(zone, NR_INACTIVE) + 1;
+ } else
+ imbalance = mem_cgroup_reclaim_imbalance(sc->mem_cgroup);
+
+ /*
+ * Reduce the effect of imbalance if swappiness is low,
+ * this means for a swappiness very low, the imbalance
+ * must be much higher than 100 for this logic to make
+ * the difference.
+ *
+ * Max temporary value is vm_total_pages*100.
+ */
+ imbalance *= (vm_swappiness + 1);
+ imbalance /= 100;
+
+ /*
+ * If not much of the ram is mapped, makes the imbalance
+ * less relevant, it's high priority we refill the inactive
+ * list with mapped pages only in presence of high ratio of
+ * mapped pages.
+ *
+ * Max temporary value is vm_total_pages*100.
+ */
+ imbalance *= mapped_ratio;
+ imbalance /= 100;
+
+ /* apply imbalance feedback to swap_tendency */
+ swap_tendency += imbalance;
+
+ /*
+ * Now use this metric to decide whether to start moving mapped
+ * memory onto the inactive list.
+ */
+ if (swap_tendency >= 100)
+ reclaim_mapped = 1;
+
+ return reclaim_mapped;
+}
+
+/*
* This moves pages from the active list to the inactive list.
*
* We move them the other way if the page is referenced by one or more
@@ -959,6 +1068,8 @@ static inline int zone_is_near_oom(struct zone *zone)
* The downside is that we have to touch page->_count against each page.
* But we had to alter page->flags anyway.
*/
+
+
static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
struct scan_control *sc, int priority)
{
@@ -972,100 +1083,21 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
struct pagevec pvec;
int reclaim_mapped = 0;
- if (sc->may_swap) {
- long mapped_ratio;
- long distress;
- long swap_tendency;
- long imbalance;
-
- if (zone_is_near_oom(zone))
- goto force_reclaim_mapped;
-
- /*
- * `distress' is a measure of how much trouble we're having
- * reclaiming pages. 0 -> no problems. 100 -> great trouble.
- */
- distress = 100 >> min(zone->prev_priority, priority);
-
- /*
- * The point of this algorithm is to decide when to start
- * reclaiming mapped memory instead of just pagecache. Work out
- * how much memory
- * is mapped.
- */
- mapped_ratio = ((global_page_state(NR_FILE_MAPPED) +
- global_page_state(NR_ANON_PAGES)) * 100) /
- vm_total_pages;
-
- /*
- * Now decide how much we really want to unmap some pages. The
- * mapped ratio is downgraded - just because there's a lot of
- * mapped memory doesn't necessarily mean that page reclaim
- * isn't succeeding.
- *
- * The distress ratio is important - we don't want to start
- * going oom.
- *
- * A 100% value of vm_swappiness overrides this algorithm
- * altogether.
- */
- swap_tendency = mapped_ratio / 2 + distress + sc->swappiness;
-
- /*
- * If there's huge imbalance between active and inactive
- * (think active 100 times larger than inactive) we should
- * become more permissive, or the system will take too much
- * cpu before it start swapping during memory pressure.
- * Distress is about avoiding early-oom, this is about
- * making swappiness graceful despite setting it to low
- * values.
- *
- * Avoid div by zero with nr_inactive+1, and max resulting
- * value is vm_total_pages.
- */
- imbalance = zone_page_state(zone, NR_ACTIVE);
- imbalance /= zone_page_state(zone, NR_INACTIVE) + 1;
-
- /*
- * Reduce the effect of imbalance if swappiness is low,
- * this means for a swappiness very low, the imbalance
- * must be much higher than 100 for this logic to make
- * the difference.
- *
- * Max temporary value is vm_total_pages*100.
- */
- imbalance *= (vm_swappiness + 1);
- imbalance /= 100;
-
- /*
- * If not much of the ram is mapped, makes the imbalance
- * less relevant, it's high priority we refill the inactive
- * list with mapped pages only in presence of high ratio of
- * mapped pages.
- *
- * Max temporary value is vm_total_pages*100.
- */
- imbalance *= mapped_ratio;
- imbalance /= 100;
-
- /* apply imbalance feedback to swap_tendency */
- swap_tendency += imbalance;
-
- /*
- * Now use this metric to decide whether to start moving mapped
- * memory onto the inactive list.
- */
- if (swap_tendency >= 100)
-force_reclaim_mapped:
- reclaim_mapped = 1;
- }
+ if (sc->may_swap)
+ reclaim_mapped = calc_reclaim_mapped(sc, zone, priority);
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
pgmoved = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order,
ISOLATE_ACTIVE, zone,
sc->mem_cgroup, 1);
- zone->pages_scanned += pgscanned;
+ /*
+ * zone->pages_scanned is used for detect zone's oom
+ * mem_cgroup remembers nr_scan by itself.
+ */
+ if (scan_global_lru(sc))
+ zone->pages_scanned += pgscanned;
+
__mod_zone_page_state(zone, NR_ACTIVE, -pgmoved);
spin_unlock_irq(&zone->lru_lock);
@@ -1155,25 +1187,39 @@ static unsigned long shrink_zone(int priority, struct zone *zone,
unsigned long nr_to_scan;
unsigned long nr_reclaimed = 0;
- /*
- * Add one to `nr_to_scan' just to make sure that the kernel will
- * slowly sift through the active list.
- */
- zone->nr_scan_active +=
- (zone_page_state(zone, NR_ACTIVE) >> priority) + 1;
- nr_active = zone->nr_scan_active;
- if (nr_active >= sc->swap_cluster_max)
- zone->nr_scan_active = 0;
- else
- nr_active = 0;
+ if (scan_global_lru(sc)) {
+ /*
+ * Add one to nr_to_scan just to make sure that the kernel
+ * will slowly sift through the active list.
+ */
+ zone->nr_scan_active +=
+ (zone_page_state(zone, NR_ACTIVE) >> priority) + 1;
+ nr_active = zone->nr_scan_active;
+ zone->nr_scan_inactive +=
+ (zone_page_state(zone, NR_INACTIVE) >> priority) + 1;
+ nr_inactive = zone->nr_scan_inactive;
+ if (nr_inactive >= sc->swap_cluster_max)
+ zone->nr_scan_inactive = 0;
+ else
+ nr_inactive = 0;
+
+ if (nr_active >= sc->swap_cluster_max)
+ zone->nr_scan_active = 0;
+ else
+ nr_active = 0;
+ } else {
+ /*
+ * This reclaim occurs not because zone memory shortage but
+ * because memory controller hits its limit.
+ * Then, don't modify zone reclaim related data.
+ */
+ nr_active = mem_cgroup_calc_reclaim_active(sc->mem_cgroup,
+ zone, priority);
+
+ nr_inactive = mem_cgroup_calc_reclaim_inactive(sc->mem_cgroup,
+ zone, priority);
+ }
- zone->nr_scan_inactive +=
- (zone_page_state(zone, NR_INACTIVE) >> priority) + 1;
- nr_inactive = zone->nr_scan_inactive;
- if (nr_inactive >= sc->swap_cluster_max)
- zone->nr_scan_inactive = 0;
- else
- nr_inactive = 0;
while (nr_active || nr_inactive) {
if (nr_active) {
@@ -1218,25 +1264,39 @@ static unsigned long shrink_zones(int priority, struct zone **zones,
unsigned long nr_reclaimed = 0;
int i;
+
sc->all_unreclaimable = 1;
for (i = 0; zones[i] != NULL; i++) {
struct zone *zone = zones[i];
if (!populated_zone(zone))
continue;
+ /*
+ * Take care memory controller reclaiming has small influence
+ * to global LRU.
+ */
+ if (scan_global_lru(sc)) {
+ if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
+ continue;
+ note_zone_scanning_priority(zone, priority);
- if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
- continue;
-
- note_zone_scanning_priority(zone, priority);
-
- if (zone_is_all_unreclaimable(zone) && priority != DEF_PRIORITY)
- continue; /* Let kswapd poll it */
-
- sc->all_unreclaimable = 0;
+ if (zone_is_all_unreclaimable(zone) &&
+ priority != DEF_PRIORITY)
+ continue; /* Let kswapd poll it */
+ sc->all_unreclaimable = 0;
+ } else {
+ /*
+ * Ignore cpuset limitation here. We just want to reduce
+ * # of used pages by us regardless of memory shortage.
+ */
+ sc->all_unreclaimable = 0;
+ mem_cgroup_note_reclaim_priority(sc->mem_cgroup,
+ priority);
+ }
nr_reclaimed += shrink_zone(priority, zone, sc);
}
+
return nr_reclaimed;
}
@@ -1264,16 +1324,21 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
unsigned long lru_pages = 0;
int i;
- count_vm_event(ALLOCSTALL);
-
- for (i = 0; zones[i] != NULL; i++) {
- struct zone *zone = zones[i];
+ if (scan_global_lru(sc))
+ count_vm_event(ALLOCSTALL);
+ /*
+ * mem_cgroup will not do shrink_slab.
+ */
+ if (scan_global_lru(sc)) {
+ for (i = 0; zones[i] != NULL; i++) {
+ struct zone *zone = zones[i];
- if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
- continue;
+ if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
+ continue;
- lru_pages += zone_page_state(zone, NR_ACTIVE)
- + zone_page_state(zone, NR_INACTIVE);
+ lru_pages += zone_page_state(zone, NR_ACTIVE)
+ + zone_page_state(zone, NR_INACTIVE);
+ }
}
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
@@ -1330,14 +1395,19 @@ out:
*/
if (priority < 0)
priority = 0;
- for (i = 0; zones[i] != NULL; i++) {
- struct zone *zone = zones[i];
- if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
- continue;
+ if (scan_global_lru(sc)) {
+ for (i = 0; zones[i] != NULL; i++) {
+ struct zone *zone = zones[i];
+
+ if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
+ continue;
+
+ zone->prev_priority = priority;
+ }
+ } else
+ mem_cgroup_record_reclaim_priority(sc->mem_cgroup, priority);
- zone->prev_priority = priority;
- }
return ret;
}