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-rw-r--r--mm/vmscan.c126
1 files changed, 75 insertions, 51 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 403f59edd53e..1ecc648b6191 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -116,6 +116,16 @@ struct scan_control {
/* Number of pages freed so far during a call to shrink_zones() */
unsigned long nr_reclaimed;
+
+ struct {
+ unsigned int dirty;
+ unsigned int unqueued_dirty;
+ unsigned int congested;
+ unsigned int writeback;
+ unsigned int immediate;
+ unsigned int file_taken;
+ unsigned int taken;
+ } nr;
};
#ifdef ARCH_HAS_PREFETCH
@@ -1755,23 +1765,6 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
free_unref_page_list(&page_list);
/*
- * If reclaim is isolating dirty pages under writeback, it implies
- * that the long-lived page allocation rate is exceeding the page
- * laundering rate. Either the global limits are not being effective
- * at throttling processes due to the page distribution throughout
- * zones or there is heavy usage of a slow backing device. The
- * only option is to throttle from reclaim context which is not ideal
- * as there is no guarantee the dirtying process is throttled in the
- * same way balance_dirty_pages() manages.
- *
- * Once a node is flagged PGDAT_WRITEBACK, kswapd will count the number
- * of pages under pages flagged for immediate reclaim and stall if any
- * are encountered in the nr_immediate check below.
- */
- if (stat.nr_writeback && stat.nr_writeback == nr_taken)
- set_bit(PGDAT_WRITEBACK, &pgdat->flags);
-
- /*
* If dirty pages are scanned that are not queued for IO, it
* implies that flushers are not doing their job. This can
* happen when memory pressure pushes dirty pages to the end of
@@ -1785,40 +1778,14 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
if (stat.nr_unqueued_dirty == nr_taken)
wakeup_flusher_threads(WB_REASON_VMSCAN);
- /*
- * Legacy memcg will stall in page writeback so avoid forcibly
- * stalling here.
- */
- if (sane_reclaim(sc)) {
- /*
- * Tag a node as congested if all the dirty pages scanned were
- * backed by a congested BDI and wait_iff_congested will stall.
- */
- if (stat.nr_dirty && stat.nr_dirty == stat.nr_congested)
- set_bit(PGDAT_CONGESTED, &pgdat->flags);
-
- /* Allow kswapd to start writing pages during reclaim. */
- if (stat.nr_unqueued_dirty == nr_taken)
- set_bit(PGDAT_DIRTY, &pgdat->flags);
-
- /*
- * If kswapd scans pages marked marked for immediate
- * reclaim and under writeback (nr_immediate), it implies
- * that pages are cycling through the LRU faster than
- * they are written so also forcibly stall.
- */
- if (stat.nr_immediate)
- congestion_wait(BLK_RW_ASYNC, HZ/10);
- }
-
- /*
- * Stall direct reclaim for IO completions if underlying BDIs and node
- * is congested. Allow kswapd to continue until it starts encountering
- * unqueued dirty pages or cycling through the LRU too quickly.
- */
- if (!sc->hibernation_mode && !current_is_kswapd() &&
- current_may_throttle())
- wait_iff_congested(pgdat, BLK_RW_ASYNC, HZ/10);
+ sc->nr.dirty += stat.nr_dirty;
+ sc->nr.congested += stat.nr_congested;
+ sc->nr.unqueued_dirty += stat.nr_unqueued_dirty;
+ sc->nr.writeback += stat.nr_writeback;
+ sc->nr.immediate += stat.nr_immediate;
+ sc->nr.taken += nr_taken;
+ if (file)
+ sc->nr.file_taken += nr_taken;
trace_mm_vmscan_lru_shrink_inactive(pgdat->node_id,
nr_scanned, nr_reclaimed,
@@ -2522,6 +2489,8 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
unsigned long node_lru_pages = 0;
struct mem_cgroup *memcg;
+ memset(&sc->nr, 0, sizeof(sc->nr));
+
nr_reclaimed = sc->nr_reclaimed;
nr_scanned = sc->nr_scanned;
@@ -2587,6 +2556,61 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
if (sc->nr_reclaimed - nr_reclaimed)
reclaimable = true;
+ /*
+ * If reclaim is isolating dirty pages under writeback, it
+ * implies that the long-lived page allocation rate is exceeding
+ * the page laundering rate. Either the global limits are not
+ * being effective at throttling processes due to the page
+ * distribution throughout zones or there is heavy usage of a
+ * slow backing device. The only option is to throttle from
+ * reclaim context which is not ideal as there is no guarantee
+ * the dirtying process is throttled in the same way
+ * balance_dirty_pages() manages.
+ *
+ * Once a node is flagged PGDAT_WRITEBACK, kswapd will count the
+ * number of pages under pages flagged for immediate reclaim and
+ * stall if any are encountered in the nr_immediate check below.
+ */
+ if (sc->nr.writeback && sc->nr.writeback == sc->nr.taken)
+ set_bit(PGDAT_WRITEBACK, &pgdat->flags);
+
+ /*
+ * Legacy memcg will stall in page writeback so avoid forcibly
+ * stalling here.
+ */
+ if (sane_reclaim(sc)) {
+ /*
+ * Tag a node as congested if all the dirty pages
+ * scanned were backed by a congested BDI and
+ * wait_iff_congested will stall.
+ */
+ if (sc->nr.dirty && sc->nr.dirty == sc->nr.congested)
+ set_bit(PGDAT_CONGESTED, &pgdat->flags);
+
+ /* Allow kswapd to start writing pages during reclaim.*/
+ if (sc->nr.unqueued_dirty == sc->nr.file_taken)
+ set_bit(PGDAT_DIRTY, &pgdat->flags);
+
+ /*
+ * If kswapd scans pages marked marked for immediate
+ * reclaim and under writeback (nr_immediate), it
+ * implies that pages are cycling through the LRU
+ * faster than they are written so also forcibly stall.
+ */
+ if (sc->nr.immediate)
+ congestion_wait(BLK_RW_ASYNC, HZ/10);
+ }
+
+ /*
+ * Stall direct reclaim for IO completions if underlying BDIs
+ * and node is congested. Allow kswapd to continue until it
+ * starts encountering unqueued dirty pages or cycling through
+ * the LRU too quickly.
+ */
+ if (!sc->hibernation_mode && !current_is_kswapd() &&
+ current_may_throttle())
+ wait_iff_congested(pgdat, BLK_RW_ASYNC, HZ/10);
+
} while (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,
sc->nr_scanned - nr_scanned, sc));