When using memory controller, there are 2 levels of memory reclaim.
1. zone memory relcaim 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.
(we can use macro "scan_global_lru")
This patch tries to make memory cgroup reclaim routine avoid affecting
system/zone memory reclaim. This patch inserts if (scan_global_lru(sc)) 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() ... calclate the number of active pages to
be scanned in this priority in mem_cgroup.
* mem_cgroup_calc_reclaim_inactive() ... calclate 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.
Signed-off-by: KAMEZAWA Hiroyuki <[EMAIL PROTECTED]>
mm/vmscan.c | 155 ++++++++++++++++++++++++++++++++++++++++--------------------
1 file changed, 105 insertions(+), 50 deletions(-)
Index: linux-2.6.24-rc2-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.24-rc2-mm1.orig/mm/vmscan.c
+++ linux-2.6.24-rc2-mm1/mm/vmscan.c
@@ -863,7 +863,8 @@ static unsigned long shrink_inactive_lis
__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;
@@ -951,22 +952,30 @@ static inline int zone_is_near_oom(struc
/*
* Determine we should try to reclaim mapped pages.
+ * This is called only when sc->mem_cgroup is NULL.
*/
-static int calc_reclaim_mapped(struct zone *zone, int priority, int swappiness)
+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;
+ int prev_priority;
- if (zone_is_near_oom(zone))
+ 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.
*/
- distress = 100 >> min(zone->prev_priority, priority);
+ 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
@@ -974,9 +983,13 @@ static int calc_reclaim_mapped(struct zo
* how much memory
* is mapped.
*/
- mapped_ratio = ((global_page_state(NR_FILE_MAPPED) +
- global_page_state(NR_ANON_PAGES)) * 100) /
- vm_total_pages;
+ 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
@@ -989,7 +1002,7 @@ static int calc_reclaim_mapped(struct zo
* A 100% value of vm_swappiness overrides this algorithm
* altogether.
*/
- swap_tendency = mapped_ratio / 2 + distress + swappiness;
+ swap_tendency = mapped_ratio / 2 + distress + sc->swappiness;
/*
* If there's huge imbalance between active and inactive
@@ -1003,8 +1016,11 @@ static int calc_reclaim_mapped(struct zo
* 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;
+ 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,
@@ -1074,15 +1090,20 @@ static void shrink_active_list(unsigned
int reclaim_mapped = 0;
if (sc->may_swap)
- reclaim_mapped = calc_reclaim_mapped(zone, priority,
- sc->swappiness);
+ 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);
@@ -1175,25 +1196,39 @@ static unsigned long shrink_zone(int pri
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 relcaim 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) {
@@ -1238,6 +1273,7 @@ static unsigned long shrink_zones(int pr
unsigned long nr_reclaimed = 0;
int i;
+
sc->all_unreclaimable = 1;
for (i = 0; zones[i] != NULL; i++) {
struct zone *zone = zones[i];
@@ -1247,16 +1283,26 @@ static unsigned long shrink_zones(int pr
if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
continue;
+ /*
+ * Take care memory controller reclaiming has minimal influence
+ * to global LRU.
+ */
+ if (scan_global_lru(sc)) {
+ note_zone_scanning_priority(zone, priority);
- 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 {
+ sc->all_unreclaimable = 0;
+ mem_cgroup_note_reclaim_priority(sc->mem_cgroup,
+ priority);
+ }
nr_reclaimed += shrink_zone(priority, zone, sc);
}
+
return nr_reclaimed;
}
@@ -1285,15 +1331,19 @@ static unsigned long do_try_to_free_page
int i;
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];
- 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--) {
@@ -1350,14 +1400,19 @@ 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;
}
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