[PATCH v9 08/25] dept: Apply sdt_might_sleep_{start,end}() to PG_{locked,writeback} wait

[Byungchul Park <max.byungchul.park@gmail.com>]

Makes Dept able to track dependencies by PG_{locked,writeback} waits.

Signed-off-by: Byungchul Park <max.byungchul.park@gmail.com>
---
 mm/filemap.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/mm/filemap.c b/mm/filemap.c
index c4d4ace..adc49cb 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -42,6 +42,7 @@
 #include <linux/ramfs.h>
 #include <linux/page_idle.h>
 #include <linux/migrate.h>
+#include <linux/dept_sdt.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 #include "internal.h"
@@ -1215,6 +1216,9 @@ static inline bool folio_trylock_flag(struct folio *folio, int bit_nr,
 /* How many times do we accept lock stealing from under a waiter? */
 int sysctl_page_lock_unfairness = 5;
 
+static struct dept_map __maybe_unused PG_locked_map = DEPT_MAP_INITIALIZER(PG_locked_map, NULL);
+static struct dept_map __maybe_unused PG_writeback_map = DEPT_MAP_INITIALIZER(PG_writeback_map, NULL);
+
 static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
 		int state, enum behavior behavior)
 {
@@ -1226,6 +1230,11 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
 	unsigned long pflags;
 	bool in_thrashing;
 
+	if (bit_nr == PG_locked)
+		sdt_might_sleep_start(&PG_locked_map);
+	else if (bit_nr == PG_writeback)
+		sdt_might_sleep_start(&PG_writeback_map);
+
 	if (bit_nr == PG_locked &&
 	    !folio_test_uptodate(folio) && folio_test_workingset(folio)) {
 		delayacct_thrashing_start(&in_thrashing);
@@ -1327,6 +1336,8 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
 	 */
 	finish_wait(q, wait);
 
+	sdt_might_sleep_end();
+
 	if (thrashing) {
 		delayacct_thrashing_end(&in_thrashing);
 		psi_memstall_leave(&pflags);
-- 
1.9.1