}
/*
- * Are there way too many processes in the direct reclaim path already?
+ * A direct reclaimer may isolate SWAP_CLUSTER_MAX pages from the LRU list and
+ * then get resheduled. When there are massive number of tasks doing page
+ * allocation, such sleeping direct reclaimers may keep piling up on each CPU,
+ * the LRU list will go small and be scanned faster than necessary, leading to
+ * unnecessary swapping, thrashing and OOM.
*/
static int too_many_isolated(struct zone *zone, int file,
struct scan_control *sc)
isolated = zone_page_state(zone, NR_ISOLATED_ANON);
}
+ /*
+ * GFP_NOIO/GFP_NOFS callers are allowed to isolate more pages, so they
+ * won't get blocked by normal direct-reclaimers, forming a circular
+ * deadlock.
+ */
+ if ((sc->gfp_mask & GFP_IOFS) == GFP_IOFS)
+ inactive >>= 3;
+
return isolated > inactive;
}
int nid;
if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) {
- for_each_node_state(nid, N_HIGH_MEMORY) {
+ for_each_node_state(nid, N_MEMORY) {
pg_data_t *pgdat = NODE_DATA(nid);
const struct cpumask *mask;
int nid;
swap_setup();
- for_each_node_state(nid, N_HIGH_MEMORY)
+ for_each_node_state(nid, N_MEMORY)
kswapd_run(nid);
hotcpu_notifier(cpu_callback, 0);
return 0;