Re: [PATCH v3 3/3] memory tiering: count PGPROMOTE_SUCCESS when mem tiering is enabled.

[Kefeng Wang]

On 2024/7/24 21:01, Zi Yan wrote:
> memory tiering can be enabled/disabled at runtime and
> sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING is used to check
> it. In migrate_misplaced_folio(), the check is missing when
> PGPROMOTE_SUCCESS is incremented. Add the missing check.
>
> Reported-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> Closes: https://lore.kernel.org/linux-mm/f4ae2c9c-fe40-4807-bdb2-64cf2d716c1a@xxxxxxxxxx/
> Fixes: 33024536bafd ("memory tiering: hot page selection with hint page fault latency")
> Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>

> ---
>   mm/migrate.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index e7296c0fb5d5..826afb82ca56 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2630,7 +2630,9 @@ int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma,
>   		putback_movable_pages(&migratepages);
>   	if (nr_succeeded) {
>   		count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded);
> -		if (!node_is_toptier(folio_nid(folio)) && node_is_toptier(node))
> +		if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING)
> +		    && !node_is_toptier(folio_nid(folio))
> +		    && node_is_toptier(node))
>   			mod_node_page_state(pgdat, PGPROMOTE_SUCCESS,
>   					    nr_succeeded);
>   	}