[PATCH v4 6/9] mm/vmscan: pass scan_control to mm_vmscan_reclaim_pages

[Ridong Chen]

From: Ridong Chen <chenridong@xxxxxxxxxx>

reclaim_folio_list() passes sc.nr_scanned to mm_vmscan_reclaim_pages as
a bare argument. Pass the enclosing struct scan_control instead and read
nr_scanned out in TP_fast_assign, consistent with the other reclaim
tracepoints. nr_reclaimed stays a separate argument: it is the return
value of shrink_folio_list(), which does not update sc->nr_reclaimed.

No functional change. The tracefs event format (TP_STRUCT__entry and
TP_printk) is unchanged, so tracefs-based consumers are unaffected.
BPF programs attached via raw_tp/tp_btf see the new TP_PROTO and need
to be adjusted; tracepoints are not a stable ABI (see
Documentation/bpf/bpf_design_QA.rst).

Assisted-by: LLM
Signed-off-by: Ridong Chen <chenridong@xxxxxxxxxx>
---
 mm/trace_vmscan.h | 10 +++++-----
 mm/vmscan.c       |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h
index b1b329039e14..54168ad45f6e 100644
--- a/mm/trace_vmscan.h
+++ b/mm/trace_vmscan.h
@@ -418,11 +418,11 @@ TRACE_EVENT(mm_vmscan_write_folio,
 
 TRACE_EVENT(mm_vmscan_reclaim_pages,
 
-	TP_PROTO(int nid,
-		unsigned long nr_scanned, unsigned long nr_reclaimed,
-		struct reclaim_stat *stat),
+	TP_PROTO(int nid, struct scan_control *sc,
+		 unsigned long nr_reclaimed,
+		 struct reclaim_stat *stat),
 
-	TP_ARGS(nid, nr_scanned, nr_reclaimed, stat),
+	TP_ARGS(nid, sc, nr_reclaimed, stat),
 
 	TP_STRUCT__entry(
 		__field(int, nid)
@@ -440,7 +440,7 @@ TRACE_EVENT(mm_vmscan_reclaim_pages,
 
 	TP_fast_assign(
 		__entry->nid = nid;
-		__entry->nr_scanned = nr_scanned;
+		__entry->nr_scanned = sc->nr_scanned;
 		__entry->nr_reclaimed = nr_reclaimed;
 		__entry->nr_dirty = stat->nr_dirty;
 		__entry->nr_writeback = stat->nr_writeback;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 5d5eee757c61..4bb00371a67f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2178,7 +2178,7 @@ static unsigned int reclaim_folio_list(struct list_head *folio_list,
 		list_del(&folio->lru);
 		folio_putback_lru(folio);
 	}
-	trace_mm_vmscan_reclaim_pages(pgdat->node_id, sc.nr_scanned, nr_reclaimed, &stat);
+	trace_mm_vmscan_reclaim_pages(pgdat->node_id, &sc, nr_reclaimed, &stat);
 
 	return nr_reclaimed;
 }
-- 
2.34.1