On 2024/7/19 22:43, Zi Yan wrote:
last_cpupid is only available when memory tiering is off or the folio
is in toptier node. Complete the check to read last_cpupid when it is
available.
Before the fix, the default last_cpupid will be used even if memory
tiering mode is turned off at runtime instead of the actual value. This
can prevent task_numa_fault() from getting right numa fault stats, but
should not cause any crash. User might see performance changes after the
fix.
Reported-by: David Hildenbrand <david@xxxxxxxxxx>
Closes: https://lore.kernel.org/linux-mm/9af34a6b-ca56-4a64-8aa6-ade65f109288@xxxxxxxxxx/
Fixes: 33024536bafd ("memory tiering: hot page selection with hint page fault latency")
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
and we better to check numabalance mode in migrate_misplaced_folio()?
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2630,7 +2630,8 @@ 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);
}
---
mm/huge_memory.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f4be468e06a4..825317aee88e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1712,7 +1712,8 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
* For memory tiering mode, cpupid of slow memory page is used
* to record page access time. So use default value.
*/
- if (node_is_toptier(nid))
+ if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) ||
+ node_is_toptier(nid))
last_cpupid = folio_last_cpupid(folio);
target_nid = numa_migrate_prep(folio, vmf, haddr, nid, &flags);
if (target_nid == NUMA_NO_NODE)
