[-next,v6,2/2] mm: vmscan: add new event to trace shrink lru

Commit Message

Bixuan Cui Jan. 5, 2024, 1:36 a.m. UTC

From: cuibixuan <[e-mail]>

Page reclaim is an important part of memory reclaim, including:
  * shrink_active_list(), moves folios from the active LRU to the inactive LRU
  * shrink_inactive_list(), shrink lru from inactive LRU list

Add the new events to calculate the execution time to better evaluate 
the entire memory recycling ratio.

Example of output:
         kswapd0-103     [007] .....  1098.353020: mm_vmscan_lru_shrink_active_start: nid=0
         kswapd0-103     [007] .....  1098.353040: mm_vmscan_lru_shrink_active_end: nid=0 nr_taken=32 nr_active=0 nr_deactivated=32 nr_referenced=0 priority=6 flags=RECLAIM_WB_FILE|RECLAIM_WB_ASYNC
         kswapd0-103     [007] .....  1098.353040: mm_vmscan_lru_shrink_inactive_start: nid=0
         kswapd0-103     [007] .....  1098.353094: mm_vmscan_lru_shrink_inactive_end: nid=0 nr_scanned=32 nr_reclaimed=0 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=0 nr_ref_keep=32 nr_unmap_fail=0 priority=6 flags=RECLAIM_WB_ANON|RECLAIM_WB_ASYNC
         kswapd0-103     [007] .....  1098.353094: mm_vmscan_lru_shrink_inactive_start: nid=0
         kswapd0-103     [007] .....  1098.353162: mm_vmscan_lru_shrink_inactive_end: nid=0 nr_scanned=32 nr_reclaimed=21 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=0 nr_ref_keep=11 nr_unmap_fail=0 priority=6 flags=RECLAIM_WB_FILE|RECLAIM_WB_ASYNC

Signed-off-by: Bixuan Cui <[e-mail]>
Reviewed-by: Andrew Morton <[e-mail]>
Reviewed-by: Steven Rostedt (Google) <[e-mail]>
---
Changes:
v6: * Add Reviewed-by from Steven Rostedt.
v5: * Use 'DECLARE_EVENT_CLASS(mm_vmscan_lru_shrink_start_template' to
replace 'RACE_EVENT(mm_vmscan_lru_shrink_inactive/active_start'
    * Add the explanation for adding new shrink lru events into 'mm: vmscan: add new event to trace shrink lru'
v4: * Add Reviewed-by and Changlog to every patch.
v3: * Swap the positions of 'nid' and 'freeable' to prevent the hole in the trace event.
v2: * Modify trace_mm_vmscan_lru_shrink_inactive() in evict_folios() at the same time to fix build error (Andrew pointed out).

 include/trace/events/vmscan.h | 31 +++++++++++++++++++++++++++++--
 mm/vmscan.c                   | 11 ++++++++---
 2 files changed, 37 insertions(+), 5 deletions(-)

Patch

diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index b99cd28c9815..4793d952c248 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -395,7 +395,34 @@  TRACE_EVENT(mm_vmscan_write_folio,
 		show_reclaim_flags(__entry->reclaim_flags))
 );
 
-TRACE_EVENT(mm_vmscan_lru_shrink_inactive,
+DECLARE_EVENT_CLASS(mm_vmscan_lru_shrink_start_template,
+
+	TP_PROTO(int nid),
+
+	TP_ARGS(nid),
+
+	TP_STRUCT__entry(
+		__field(int, nid)
+	),
+
+	TP_fast_assign(
+		__entry->nid = nid;
+	),
+
+	TP_printk("nid=%d", __entry->nid)
+);
+
+DEFINE_EVENT(mm_vmscan_lru_shrink_start_template, mm_vmscan_lru_shrink_inactive_start,
+	TP_PROTO(int nid),
+	TP_ARGS(nid)
+);
+
+DEFINE_EVENT(mm_vmscan_lru_shrink_start_template, mm_vmscan_lru_shrink_active_start,
+	TP_PROTO(int nid),
+	TP_ARGS(nid)
+);
+
+TRACE_EVENT(mm_vmscan_lru_shrink_inactive_end,
 
 	TP_PROTO(int nid,
 		unsigned long nr_scanned, unsigned long nr_reclaimed,
@@ -446,7 +473,7 @@  TRACE_EVENT(mm_vmscan_lru_shrink_inactive,
 		show_reclaim_flags(__entry->reclaim_flags))
 );
 
-TRACE_EVENT(mm_vmscan_lru_shrink_active,
+TRACE_EVENT(mm_vmscan_lru_shrink_active_end,
 
 	TP_PROTO(int nid, unsigned long nr_taken,
 		unsigned long nr_active, unsigned long nr_deactivated,
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4e3b835c6b4a..a44d9624d60f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1906,6 +1906,8 @@  static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 	bool stalled = false;
 
+	trace_mm_vmscan_lru_shrink_inactive_start(pgdat->node_id);
+
 	while (unlikely(too_many_isolated(pgdat, file, sc))) {
 		if (stalled)
 			return 0;
@@ -1990,7 +1992,7 @@  static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
 	if (file)
 		sc->nr.file_taken += nr_taken;
 
-	trace_mm_vmscan_lru_shrink_inactive(pgdat->node_id,
+	trace_mm_vmscan_lru_shrink_inactive_end(pgdat->node_id,
 			nr_scanned, nr_reclaimed, &stat, sc->priority, file);
 	return nr_reclaimed;
 }
@@ -2028,6 +2030,8 @@  static void shrink_active_list(unsigned long nr_to_scan,
 	int file = is_file_lru(lru);
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 
+	trace_mm_vmscan_lru_shrink_active_start(pgdat->node_id);
+
 	lru_add_drain();
 
 	spin_lock_irq(&lruvec->lru_lock);
@@ -2107,7 +2111,7 @@  static void shrink_active_list(unsigned long nr_to_scan,
 		lru_note_cost(lruvec, file, 0, nr_rotated);
 	mem_cgroup_uncharge_list(&l_active);
 	free_unref_page_list(&l_active);
-	trace_mm_vmscan_lru_shrink_active(pgdat->node_id, nr_taken, nr_activate,
+	trace_mm_vmscan_lru_shrink_active_end(pgdat->node_id, nr_taken, nr_activate,
 			nr_deactivate, nr_rotated, sc->priority, file);
 }
 
@@ -4524,9 +4528,10 @@  static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap
 	if (list_empty(&list))
 		return scanned;
 retry:
+	trace_mm_vmscan_lru_shrink_inactive_start(pgdat->node_id);
 	reclaimed = shrink_folio_list(&list, pgdat, sc, &stat, false);
 	sc->nr_reclaimed += reclaimed;
-	trace_mm_vmscan_lru_shrink_inactive(pgdat->node_id,
+	trace_mm_vmscan_lru_shrink_inactive_end(pgdat->node_id,
 			scanned, reclaimed, &stat, sc->priority,
 			type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);