On 9 Jan 2023 12:33:36 +0900 Byungchul Park <byungchul.park@xxxxxxx>
> Makes Dept able to track dependencies by PG_{locked,writeback} waits.
>
> Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
> ---
Hey Byungchul
Is DEPT able to get deadlock reported for the syzbot report [1]?
Hillf
[1] https://lore.kernel.org/lkml/6383cde5-cf4b-facf-6e07-1378a485657d@xxxxxxxxxxxxxxxxxxx/
> mm/filemap.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index c4d4ace..b013a5b 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_strong(&PG_locked_map);
> + else if (bit_nr == PG_writeback)
> + sdt_might_sleep_strong(&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_finish();
> +
> if (thrashing) {
> delayacct_thrashing_end(&in_thrashing);
> psi_memstall_leave(&pflags);
> --
> 1.9.1
