thp: use compaction in kswapd for GFP_ATOMIC order > 0
This takes advantage of memory compaction to properly generate pages of
order > 0 if regular page reclaim fails and priority level becomes more
severe and we don't reach the proper watermarks.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/compaction.c b/mm/compaction.c
index da25b5a..60d52a7 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -42,6 +42,8 @@
unsigned int order; /* order a direct compactor needs */
int migratetype; /* MOVABLE, RECLAIMABLE etc */
struct zone *zone;
+
+ int compact_mode;
};
static unsigned long release_freepages(struct list_head *freelist)
@@ -382,10 +384,10 @@
}
static int compact_finished(struct zone *zone,
- struct compact_control *cc)
+ struct compact_control *cc)
{
unsigned int order;
- unsigned long watermark = low_wmark_pages(zone) + (1 << cc->order);
+ unsigned long watermark;
if (fatal_signal_pending(current))
return COMPACT_PARTIAL;
@@ -395,12 +397,27 @@
return COMPACT_COMPLETE;
/* Compaction run is not finished if the watermark is not met */
+ if (cc->compact_mode != COMPACT_MODE_KSWAPD)
+ watermark = low_wmark_pages(zone);
+ else
+ watermark = high_wmark_pages(zone);
+ watermark += (1 << cc->order);
+
if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0))
return COMPACT_CONTINUE;
if (cc->order == -1)
return COMPACT_CONTINUE;
+ /*
+ * Generating only one page of the right order is not enough
+ * for kswapd, we must continue until we're above the high
+ * watermark as a pool for high order GFP_ATOMIC allocations
+ * too.
+ */
+ if (cc->compact_mode == COMPACT_MODE_KSWAPD)
+ return COMPACT_CONTINUE;
+
/* Direct compactor: Is a suitable page free? */
for (order = cc->order; order < MAX_ORDER; order++) {
/* Job done if page is free of the right migratetype */
@@ -514,8 +531,9 @@
}
unsigned long compact_zone_order(struct zone *zone,
- int order, gfp_t gfp_mask,
- bool sync)
+ int order, gfp_t gfp_mask,
+ bool sync,
+ int compact_mode)
{
struct compact_control cc = {
.nr_freepages = 0,
@@ -524,6 +542,7 @@
.migratetype = allocflags_to_migratetype(gfp_mask),
.zone = zone,
.sync = sync,
+ .compact_mode = compact_mode,
};
INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages);
@@ -569,7 +588,8 @@
nodemask) {
int status;
- status = compact_zone_order(zone, order, gfp_mask, sync);
+ status = compact_zone_order(zone, order, gfp_mask, sync,
+ COMPACT_MODE_DIRECT_RECLAIM);
rc = max(status, rc);
/* If a normal allocation would succeed, stop compacting */
@@ -600,6 +620,7 @@
.nr_freepages = 0,
.nr_migratepages = 0,
.order = -1,
+ .compact_mode = COMPACT_MODE_DIRECT_RECLAIM,
};
zone = &pgdat->node_zones[zoneid];