Re: [PATCH 2/2] mm/vmscan: make sure wakeup_kswapd with managed zone

Huang, Ying
2022-03-28T01:08:43Z

Hi, Wei,

Wei Yang <richard.weiyang@gmail.com> writes:

> wakeup_kswapd() only wake up kswapd when the zone is managed.
>
> For two callers of wakeup_kswapd(), they are node perspective.
>
> * wake_all_kswapds
> * numamigrate_isolate_page
>
> If we picked up a !managed zone, this is not we expected.
>
> This patch makes sure we pick up a managed zone for wakeup_kswapd().
>
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> ---
> mm/migrate.c | 2 +-
> mm/page_alloc.c | 2 ++
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 3d60823afd2d..c4b654c0bdf0 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2046,7 +2046,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
> if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING))
> return 0;
> for (z = pgdat->nr_zones - 1; z >= 0; z--) {
> - if (populated_zone(pgdat->node_zones + z))
> + if (managed_zone(pgdat->node_zones + z))

This looks good to me! Thanks! It seems that we can replace
populated_zone() in migrate_balanced_pgdat() too. Right?

> break;
> }
> wakeup_kswapd(pgdat->node_zones + z, 0, order, ZONE_MOVABLE);
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 4c0c4ef94ba0..6656c2d06e01 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -4674,6 +4674,8 @@ static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
>
> for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx,
> ac->nodemask) {
> + if (!managed_zone(zone))
> + continue;
> if (last_pgdat != zone->zone_pgdat)
> wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx);
> last_pgdat = zone->zone_pgdat;

Best Regards,
Huang, Ying