mm: multi-gen LRU: reuse some legacy trace events

As the legacy lru provides, the mglru needs some trace events for
debugging.  Let's reuse following legacy events for the mglru.

  trace_mm_vmscan_lru_isolate
  trace_mm_vmscan_lru_shrink_inactive

Here's an example
  mm_vmscan_lru_isolate: classzone=2 order=0 nr_requested=4096 nr_scanned=64 nr_skipped=0 nr_taken=64 lru=inactive_file
  mm_vmscan_lru_shrink_inactive: nid=0 nr_scanned=64 nr_reclaimed=63 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=1 nr_ref_keep=0 nr_unmap_fail=0 priority=2 flags=RECLAIM_WB_FILE|RECLAIM_WB_ASYNC

Link: https://lkml.kernel.org/r/20231003114155.21869-1-jaewon31.kim@samsung.com
Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: T.J. Mercier <tjmercier@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 55424215f75944ae7bd1b99ce714c7fd28f3c311..506f8220c5fe5384678182628b78d1519ea8fc26 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4304,6 +4304,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
        int sorted = 0;
        int scanned = 0;
        int isolated = 0;
+       int skipped = 0;
        int remaining = MAX_LRU_BATCH;
        struct lru_gen_folio *lrugen = &lruvec->lrugen;
        struct mem_cgroup *memcg = lruvec_memcg(lruvec);
@@ -4317,7 +4318,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
 
        for (i = MAX_NR_ZONES; i > 0; i--) {
                LIST_HEAD(moved);
-               int skipped = 0;
+               int skipped_zone = 0;
                int zone = (sc->reclaim_idx + i) % MAX_NR_ZONES;
                struct list_head *head = &lrugen->folios[gen][type][zone];
 
@@ -4339,16 +4340,17 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
                                isolated += delta;
                        } else {
                                list_move(&folio->lru, &moved);
-                               skipped += delta;
+                               skipped_zone += delta;
                        }
 
-                       if (!--remaining || max(isolated, skipped) >= MIN_LRU_BATCH)
+                       if (!--remaining || max(isolated, skipped_zone) >= MIN_LRU_BATCH)
                                break;
                }
 
-               if (skipped) {
+               if (skipped_zone) {
                        list_splice(&moved, head);
-                       __count_zid_vm_events(PGSCAN_SKIP, zone, skipped);
+                       __count_zid_vm_events(PGSCAN_SKIP, zone, skipped_zone);
+                       skipped += skipped_zone;
                }
 
                if (!remaining || isolated >= MIN_LRU_BATCH)
@@ -4363,6 +4365,9 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
        __count_memcg_events(memcg, item, isolated);
        __count_memcg_events(memcg, PGREFILL, sorted);
        __count_vm_events(PGSCAN_ANON + type, isolated);
+       trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, MAX_LRU_BATCH,
+                               scanned, skipped, isolated,
+                               type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);
 
        /*
         * There might not be eligible folios due to reclaim_idx. Check the
@@ -4493,6 +4498,9 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap
 retry:
        reclaimed = shrink_folio_list(&list, pgdat, sc, &stat, false);
        sc->nr_reclaimed += reclaimed;
+       trace_mm_vmscan_lru_shrink_inactive(pgdat->node_id,
+                       scanned, reclaimed, &stat, sc->priority,
+                       type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);
 
        list_for_each_entry_safe_reverse(folio, next, &list, lru) {
                if (!folio_evictable(folio)) {