On Tue Jul 23, 2024 at 6:17 AM EDT, David Hildenbrand wrote: > On 23.07.24 05:24, Kefeng Wang wrote: > > > > > > 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? > > > > PS: Could we rename folio_has_cpupid() to folio_has_access_time(), even > > without memory_tiering, we still have cpupid in folio, right? folio_has_access_time() would be the opposite of folio_has_cpupid(). If memory tiering is off (either at compile time or dynamically), a folio has cpupid all the time. > > Maybe call it "folio_use_cpupid()" or sth like that? The "has" is a bit > misleading, because the folio has a cpuid in any case, no? The folio's cpupid field is reused to record page access time, when the folio is !node_is_toptier() and memory tiering mode is on. In sum, using folio_use_access_time() as !folio_has_cpupid() seems better to me, since it covers the special use of folio's cpupid field. Let me know your thoughts. -- Best Regards, Yan, Zi
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