Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> writes: > On 2024/7/23 9:54, Zi Yan wrote: >> On Mon Jul 22, 2024 at 9:48 PM EDT, Kefeng Wang wrote: >>> >>> >>> On 2024/7/23 1:29, 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> >>> >> Thanks. >> >>>> --- >>>> mm/migrate.c | 4 +++- >>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/mm/migrate.c b/mm/migrate.c >>>> index bdbb5bb04c91..b819809da470 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); >>> >>> The should be in advance of patch2, and change above to use >>> folio_has_cpupid() helper() too. >> It shares the same logic of !folio_has_cpupid() but it might be >> confusing to >> put !folio_has_cpupid(folio) && node_is_toptier(node) here. folio's >> cpupid has nothing to do with the stats here, thus I did not use the >> function. > > If folio don't include access time, we do migrate it but it isn't a > promotion, so don't count it, other comments? Personally, I prefer to use !node_is_toptier() && node_is_toptier() here. That sounds more natural for me. > PS: Could we rename folio_has_cpupid() to folio_has_access_time(), > even without memory_tiering, we still have cpupid in folio, right? -- Best Regards, Huang, Ying
