mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure

[linux-2.6-microblaze.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 61606fa..741f169 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -108,6 +108,12 @@ struct scan_control {
        /* Can folios be swapped as part of reclaim? */
        unsigned int may_swap:1;
 
+       /* Not allow cache_trim_mode to be turned on as part of reclaim? */
+       unsigned int no_cache_trim_mode:1;
+
+       /* Has cache_trim_mode failed at least once? */
+       unsigned int cache_trim_mode_failed:1;
+
        /* Proactive reclaim invoked by userspace through memory.reclaim */
        unsigned int proactive:1;
 
@@ -2271,7 +2277,8 @@ static void prepare_scan_control(pg_data_t *pgdat, struct scan_control *sc)
         * anonymous pages.
         */
        file = lruvec_page_state(target_lruvec, NR_INACTIVE_FILE);
-       if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE))
+       if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE) &&
+           !sc->no_cache_trim_mode)
                sc->cache_trim_mode = 1;
        else
                sc->cache_trim_mode = 0;
@@ -5986,6 +5993,8 @@ again:
         */
        if (reclaimable)
                pgdat->kswapd_failures = 0;
+       else if (sc->cache_trim_mode)
+               sc->cache_trim_mode_failed = 1;
 }
 
 /*
@@ -6918,6 +6927,16 @@ restart:
                        sc.priority--;
        } while (sc.priority >= 1);
 
+       /*
+        * Restart only if it went through the priority loop all the way,
+        * but cache_trim_mode didn't work.
+        */
+       if (!sc.nr_reclaimed && sc.priority < 1 &&
+           !sc.no_cache_trim_mode && sc.cache_trim_mode_failed) {
+               sc.no_cache_trim_mode = 1;
+               goto restart;
+       }
+
        if (!sc.nr_reclaimed)
                pgdat->kswapd_failures++;