* In this context, it doesn't matter that we scan the
* whole list at once. */
int swap_cluster_max;
+
+ int swappiness;
};
/*
* A 100% value of vm_swappiness overrides this algorithm
* altogether.
*/
- swap_tendency = mapped_ratio / 2 + distress + vm_swappiness;
+ swap_tendency = mapped_ratio / 2 + distress + sc->swappiness;
/*
* Now use this metric to decide whether to start moving mapped
.may_writepage = !laptop_mode,
.swap_cluster_max = SWAP_CLUSTER_MAX,
.may_swap = 1,
+ .swappiness = vm_swappiness,
};
inc_page_state(allocstall);
* For kswapd, balance_pgdat() will work across all this node's zones until
* they are all at pages_high.
*
- * If `nr_pages' is non-zero then it is the number of pages which are to be
- * reclaimed, regardless of the zone occupancies. This is a software suspend
- * special.
- *
* Returns the number of pages which were actually freed.
*
* There is special handling here for zones which are full of pinned pages.
* the page allocator fallback scheme to ensure that aging of pages is balanced
* across the zones.
*/
-static unsigned long balance_pgdat(pg_data_t *pgdat, unsigned long nr_pages,
- int order)
+static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
{
- unsigned long to_free = nr_pages;
int all_zones_ok;
int priority;
int i;
struct scan_control sc = {
.gfp_mask = GFP_KERNEL,
.may_swap = 1,
- .swap_cluster_max = nr_pages ? nr_pages : SWAP_CLUSTER_MAX,
+ .swap_cluster_max = SWAP_CLUSTER_MAX,
+ .swappiness = vm_swappiness,
};
loop_again:
all_zones_ok = 1;
- if (nr_pages == 0) {
- /*
- * Scan in the highmem->dma direction for the highest
- * zone which needs scanning
- */
- for (i = pgdat->nr_zones - 1; i >= 0; i--) {
- struct zone *zone = pgdat->node_zones + i;
+ /*
+ * Scan in the highmem->dma direction for the highest
+ * zone which needs scanning
+ */
+ for (i = pgdat->nr_zones - 1; i >= 0; i--) {
+ struct zone *zone = pgdat->node_zones + i;
- if (!populated_zone(zone))
- continue;
+ if (!populated_zone(zone))
+ continue;
- if (zone->all_unreclaimable &&
- priority != DEF_PRIORITY)
- continue;
+ if (zone->all_unreclaimable && priority != DEF_PRIORITY)
+ continue;
- if (!zone_watermark_ok(zone, order,
- zone->pages_high, 0, 0)) {
- end_zone = i;
- goto scan;
- }
+ if (!zone_watermark_ok(zone, order, zone->pages_high,
+ 0, 0)) {
+ end_zone = i;
+ goto scan;
}
- goto out;
- } else {
- end_zone = pgdat->nr_zones - 1;
}
+ goto out;
scan:
for (i = 0; i <= end_zone; i++) {
struct zone *zone = pgdat->node_zones + i;
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
continue;
- if (nr_pages == 0) { /* Not software suspend */
- if (!zone_watermark_ok(zone, order,
- zone->pages_high, end_zone, 0))
- all_zones_ok = 0;
- }
+ 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;
total_scanned > nr_reclaimed + nr_reclaimed / 2)
sc.may_writepage = 1;
}
- if (nr_pages && to_free > nr_reclaimed)
- continue; /* swsusp: need to do more work */
if (all_zones_ok)
break; /* kswapd: all done */
/*
* matches the direct reclaim path behaviour in terms of impact
* on zone->*_priority.
*/
- if ((nr_reclaimed >= SWAP_CLUSTER_MAX) && !nr_pages)
+ if (nr_reclaimed >= SWAP_CLUSTER_MAX)
break;
}
out:
}
finish_wait(&pgdat->kswapd_wait, &wait);
- balance_pgdat(pgdat, 0, order);
+ balance_pgdat(pgdat, order);
}
return 0;
}
#ifdef CONFIG_PM
/*
- * Try to free `nr_pages' of memory, system-wide. Returns the number of freed
- * pages.
+ * Helper function for shrink_all_memory(). Tries to reclaim 'nr_pages' pages
+ * from LRU lists system-wide, for given pass and priority, and returns the
+ * number of reclaimed pages
+ *
+ * For pass > 3 we also try to shrink the LRU lists that contain a few pages
+ */
+static unsigned long shrink_all_zones(unsigned long nr_pages, int pass,
+ int prio, struct scan_control *sc)
+{
+ struct zone *zone;
+ unsigned long nr_to_scan, ret = 0;
+
+ for_each_zone(zone) {
+
+ if (!populated_zone(zone))
+ continue;
+
+ if (zone->all_unreclaimable && prio != DEF_PRIORITY)
+ continue;
+
+ /* For pass = 0 we don't shrink the active list */
+ if (pass > 0) {
+ zone->nr_scan_active += (zone->nr_active >> prio) + 1;
+ 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);
+ }
+ }
+
+ zone->nr_scan_inactive += (zone->nr_inactive >> prio) + 1;
+ if (zone->nr_scan_inactive >= nr_pages || pass > 3) {
+ zone->nr_scan_inactive = 0;
+ nr_to_scan = min(nr_pages, zone->nr_inactive);
+ ret += shrink_inactive_list(nr_to_scan, zone, sc);
+ if (ret >= nr_pages)
+ return ret;
+ }
+ }
+
+ return ret;
+}
+
+/*
+ * Try to free `nr_pages' of memory, system-wide, and return the number of
+ * freed pages.
+ *
+ * Rather than trying to age LRUs the aim is to preserve the overall
+ * LRU order by reclaiming preferentially
+ * inactive > active > active referenced > active mapped
*/
unsigned long shrink_all_memory(unsigned long nr_pages)
{
- pg_data_t *pgdat;
- unsigned long nr_to_free = nr_pages;
+ unsigned long lru_pages, nr_slab;
unsigned long ret = 0;
- unsigned retry = 2;
- struct reclaim_state reclaim_state = {
- .reclaimed_slab = 0,
+ int pass;
+ struct reclaim_state reclaim_state;
+ struct zone *zone;
+ struct scan_control sc = {
+ .gfp_mask = GFP_KERNEL,
+ .may_swap = 0,
+ .swap_cluster_max = nr_pages,
+ .may_writepage = 1,
+ .swappiness = vm_swappiness,
};
current->reclaim_state = &reclaim_state;
-repeat:
- for_each_online_pgdat(pgdat) {
- unsigned long freed;
- freed = balance_pgdat(pgdat, nr_to_free, 0);
- ret += freed;
- nr_to_free -= freed;
- if ((long)nr_to_free <= 0)
+ lru_pages = 0;
+ for_each_zone(zone)
+ lru_pages += zone->nr_active + zone->nr_inactive;
+
+ nr_slab = read_page_state(nr_slab);
+ /* If slab caches are huge, it's better to hit them first */
+ while (nr_slab >= lru_pages) {
+ reclaim_state.reclaimed_slab = 0;
+ shrink_slab(nr_pages, sc.gfp_mask, lru_pages);
+ if (!reclaim_state.reclaimed_slab)
break;
+
+ ret += reclaim_state.reclaimed_slab;
+ if (ret >= nr_pages)
+ goto out;
+
+ nr_slab -= reclaim_state.reclaimed_slab;
}
- if (retry-- && ret < nr_pages) {
- blk_congestion_wait(WRITE, HZ/5);
- goto repeat;
+
+ /*
+ * We try to shrink LRUs in 5 passes:
+ * 0 = Reclaim from inactive_list only
+ * 1 = Reclaim from active list but don't reclaim mapped
+ * 2 = 2nd pass of type 1
+ * 3 = Reclaim mapped (normal reclaim)
+ * 4 = 2nd pass of type 3
+ */
+ for (pass = 0; pass < 5; pass++) {
+ int prio;
+
+ /* Needed for shrinking slab caches later on */
+ if (!lru_pages)
+ for_each_zone(zone) {
+ lru_pages += zone->nr_active;
+ lru_pages += zone->nr_inactive;
+ }
+
+ /* Force reclaiming mapped pages in the passes #3 and #4 */
+ if (pass > 2) {
+ sc.may_swap = 1;
+ sc.swappiness = 100;
+ }
+
+ for (prio = DEF_PRIORITY; prio >= 0; prio--) {
+ unsigned long nr_to_scan = nr_pages - ret;
+
+ sc.nr_mapped = read_page_state(nr_mapped);
+ sc.nr_scanned = 0;
+
+ ret += shrink_all_zones(nr_to_scan, prio, pass, &sc);
+ if (ret >= nr_pages)
+ goto out;
+
+ reclaim_state.reclaimed_slab = 0;
+ shrink_slab(sc.nr_scanned, sc.gfp_mask, lru_pages);
+ ret += reclaim_state.reclaimed_slab;
+ if (ret >= nr_pages)
+ goto out;
+
+ if (sc.nr_scanned && prio < DEF_PRIORITY - 2)
+ blk_congestion_wait(WRITE, HZ / 10);
+ }
+
+ lru_pages = 0;
}
+
+ /*
+ * If ret = 0, we could not shrink LRUs, but there may be something
+ * in slab caches
+ */
+ if (!ret)
+ do {
+ reclaim_state.reclaimed_slab = 0;
+ shrink_slab(nr_pages, sc.gfp_mask, lru_pages);
+ ret += reclaim_state.reclaimed_slab;
+ } while (ret < nr_pages && reclaim_state.reclaimed_slab > 0);
+
+out:
current->reclaim_state = NULL;
+
return ret;
}
#endif
.swap_cluster_max = max_t(unsigned long, nr_pages,
SWAP_CLUSTER_MAX),
.gfp_mask = gfp_mask,
+ .swappiness = vm_swappiness,
};
disable_swap_token();
projects / linux-2.6 / commitdiff