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-rw-r--r--mm/vmscan.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index e5117b6897a9..2e34b61a70c7 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1572,3 +1572,71 @@ static int __init kswapd_init(void)
}
module_init(kswapd_init)
+
+#ifdef CONFIG_NUMA
+/*
+ * Zone reclaim mode
+ *
+ * If non-zero call zone_reclaim when the number of free pages falls below
+ * the watermarks.
+ *
+ * In the future we may add flags to the mode. However, the page allocator
+ * should only have to check that zone_reclaim_mode != 0 before calling
+ * zone_reclaim().
+ */
+int zone_reclaim_mode __read_mostly;
+
+/*
+ * Mininum time between zone reclaim scans
+ */
+#define ZONE_RECLAIM_INTERVAL HZ/2
+/*
+ * Try to free up some pages from this zone through reclaim.
+ */
+int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
+{
+ int nr_pages = 1 << order;
+ struct task_struct *p = current;
+ struct reclaim_state reclaim_state;
+ struct scan_control sc = {
+ .gfp_mask = gfp_mask,
+ .may_writepage = 0,
+ .may_swap = 0,
+ .nr_mapped = read_page_state(nr_mapped),
+ .nr_scanned = 0,
+ .nr_reclaimed = 0,
+ .priority = 0
+ };
+
+ if (!(gfp_mask & __GFP_WAIT) ||
+ zone->zone_pgdat->node_id != numa_node_id() ||
+ zone->all_unreclaimable ||
+ atomic_read(&zone->reclaim_in_progress) > 0)
+ return 0;
+
+ if (time_before(jiffies,
+ zone->last_unsuccessful_zone_reclaim + ZONE_RECLAIM_INTERVAL))
+ return 0;
+
+ disable_swap_token();
+
+ if (nr_pages > SWAP_CLUSTER_MAX)
+ sc.swap_cluster_max = nr_pages;
+ else
+ sc.swap_cluster_max = SWAP_CLUSTER_MAX;
+
+ cond_resched();
+ p->flags |= PF_MEMALLOC;
+ reclaim_state.reclaimed_slab = 0;
+ p->reclaim_state = &reclaim_state;
+ shrink_zone(zone, &sc);
+ p->reclaim_state = NULL;
+ current->flags &= ~PF_MEMALLOC;
+
+ if (sc.nr_reclaimed == 0)
+ zone->last_unsuccessful_zone_reclaim = jiffies;
+
+ return sc.nr_reclaimed > nr_pages;
+}
+#endif
+