Yang Shi <shy828301@xxxxxxxxx> writes:
> On Mon, Oct 19, 2020 at 12:38 AM Huang, Ying <ying.huang@xxxxxxxxx> wrote:
>>
>> Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> writes:
>>
>> > From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
>> >
>> > Account the number of demoted pages into reclaim_state->nr_demoted.
>>
>> It appears that you don't add "nr_demoted" into struct reclaim_state.
>>
>> > 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()
>>
>> It appears that we get the data from migrate_pages() now.
>>
>> > ]
>> >
>> > Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
>> > Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
>> > Cc: David Rientjes <rientjes@xxxxxxxxxx>
>> > Cc: Huang Ying <ying.huang@xxxxxxxxx>
>> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
>> > Cc: David Hildenbrand <david@xxxxxxxxxx>
>> > ---
>> >
>> > b/include/linux/vm_event_item.h | 2 ++
>> > b/mm/vmscan.c | 6 ++++++
>> > b/mm/vmstat.c | 2 ++
>> > 3 files changed, 10 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 2020-10-07 09:15:32.171642439 -0700
>> > +++ b/include/linux/vm_event_item.h 2020-10-07 09:15:32.179642439 -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 2020-10-07 09:15:32.173642439 -0700
>> > +++ b/mm/vmscan.c 2020-10-07 09:15:32.180642439 -0700
>> > @@ -147,6 +147,7 @@ struct scan_control {
>> > unsigned int immediate;
>> > unsigned int file_taken;
>> > unsigned int taken;
>> > + unsigned int demoted;
>>
>> It appears that this newly added field isn't used in the patch.
>
> My original patch tracked nr_demoted in reclaim_stat as well, but it
> seems Dave dropped that part. If Dave thinks it is not necessary to
> keep tracking nr_demoted in reclaim_stat, then that field should be
> dropped.
Personally, I prefer to collect nr_demoted in struct reclaim_stat and
call counting functions in shrink_inactive_list() as other reclaiming
statistics.
Best Regards,
Huang, Ying
>>
>> > } nr;
>> >
>> > /* for recording the reclaimed slab by now */
>> > @@ -1134,6 +1135,11 @@ 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 2020-10-07 09:15:32.175642439 -0700
>> > +++ b/mm/vmstat.c 2020-10-07 09:15:32.181642439 -0700
>> > @@ -1244,6 +1244,8 @@ const char * const vmstat_text[] = {
>> > "pgreuse",
>> > "pgsteal_kswapd",
>> > "pgsteal_direct",
>> > + "pgdemote_kswapd",
>> > + "pgdemote_direct",
>> > "pgscan_kswapd",
>> > "pgscan_direct",
>> > "pgscan_direct_throttle",
>> > _
>>
>> Best Regards,
>> Huang, Ying
>>
