2021-04-01 18:55:57

by Dave Hansen

Subject: [PATCH 06/10] mm/vmscan: add page demotion counter

From: Yang Shi <[email protected]>

Account the number of demoted pages into reclaim_state->nr_demoted.

Add pgdemote_kswapd and pgdemote_direct VM counters showed in
/proc/vmstat.

[ daveh:
- __count_vm_events() a bit, and made them look at the THP
size directly rather than getting data from migrate_pages()
]

Signed-off-by: Yang Shi <[email protected]>
Signed-off-by: Dave Hansen <[email protected]>
Reviewed-by: Yang Shi <[email protected]>
Cc: Wei Xu <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: osalvador <[email protected]>

--

Changes since 202010:
* remove unused scan-control 'demoted' field
---

b/include/linux/vm_event_item.h | 2 ++
b/mm/vmscan.c | 5 +++++
b/mm/vmstat.c | 2 ++
3 files changed, 9 insertions(+)

diff -puN include/linux/vm_event_item.h~mm-vmscan-add-page-demotion-counter include/linux/vm_event_item.h
--- a/include/linux/vm_event_item.h~mm-vmscan-add-page-demotion-counter 2021-03-31 15:17:17.079000248 -0700
+++ b/include/linux/vm_event_item.h 2021-03-31 15:17:17.101000248 -0700
@@ -33,6 +33,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
PGREUSE,
PGSTEAL_KSWAPD,
PGSTEAL_DIRECT,
+ PGDEMOTE_KSWAPD,
+ PGDEMOTE_DIRECT,
PGSCAN_KSWAPD,
PGSCAN_DIRECT,
PGSCAN_DIRECT_THROTTLE,
diff -puN mm/vmscan.c~mm-vmscan-add-page-demotion-counter mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-add-page-demotion-counter 2021-03-31 15:17:17.081000248 -0700
+++ b/mm/vmscan.c 2021-03-31 15:17:17.109000248 -0700
@@ -1120,6 +1120,11 @@ static unsigned int demote_page_list(str
target_nid, MIGRATE_ASYNC, MR_DEMOTION,
&nr_succeeded);

+ if (current_is_kswapd())
+ __count_vm_events(PGDEMOTE_KSWAPD, nr_succeeded);
+ else
+ __count_vm_events(PGDEMOTE_DIRECT, nr_succeeded);
+
return nr_succeeded;
}

diff -puN mm/vmstat.c~mm-vmscan-add-page-demotion-counter mm/vmstat.c
--- a/mm/vmstat.c~mm-vmscan-add-page-demotion-counter 2021-03-31 15:17:17.092000248 -0700
+++ b/mm/vmstat.c 2021-03-31 15:17:17.116000248 -0700
@@ -1259,6 +1259,8 @@ const char * const vmstat_text[] = {
"pgreuse",
"pgsteal_kswapd",
"pgsteal_direct",
+ "pgdemote_kswapd",
+ "pgdemote_direct",
"pgscan_kswapd",
"pgscan_direct",
"pgscan_direct_throttle",
_

2021-04-10 03:41:55

by Wei Xu

Subject: Re: [PATCH 06/10] mm/vmscan: add page demotion counter

On Thu, Apr 1, 2021 at 11:35 AM Dave Hansen <[email protected]> wrote:
>
>
> From: Yang Shi <[email protected]>
>
> Account the number of demoted pages into reclaim_state->nr_demoted.
>
> Add pgdemote_kswapd and pgdemote_direct VM counters showed in
> /proc/vmstat.
>
> [ daveh:
> - __count_vm_events() a bit, and made them look at the THP
> size directly rather than getting data from migrate_pages()
> ]
>
> Signed-off-by: Yang Shi <[email protected]>
> Signed-off-by: Dave Hansen <[email protected]>
> Reviewed-by: Yang Shi <[email protected]>
> Cc: Wei Xu <[email protected]>
> Cc: David Rientjes <[email protected]>
> Cc: Huang Ying <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: David Hildenbrand <[email protected]>
> Cc: osalvador <[email protected]>

These counters can be more useful if they are per-node.

Reviewed-by: Wei Xu <[email protected]>