From: Zi Yan Date: Wed, 24 Jul 2024 13:01:13 +0000 (-0400) Subject: memory tiering: read last_cpupid correctly in do_huge_pmd_numa_page() X-Git-Tag: v6.12-rc1~115^2~401 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3eb2091c653480e02e9c2a114c4725ec654bca63;p=thirdparty%2Fkernel%2Flinux.git memory tiering: read last_cpupid correctly in do_huge_pmd_numa_page() Patch series "Various memory tiering fixes", v3. This patch (of 3): 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. Link: https://lkml.kernel.org/r/20240724130115.793641-1-ziy@nvidia.com Link: https://lkml.kernel.org/r/20240724130115.793641-2-ziy@nvidia.com Fixes: 33024536bafd ("memory tiering: hot page selection with hint page fault latency") Signed-off-by: Zi Yan Reported-by: David Hildenbrand Closes: https://lore.kernel.org/linux-mm/9af34a6b-ca56-4a64-8aa6-ade65f109288@redhat.com/ Reviewed-by: "Huang, Ying" Reviewed-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Kefeng Wang Cc: Lorenzo Stoakes Signed-off-by: Andrew Morton --- diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1ec32c02b19c7..632a92edec4ee 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1707,7 +1707,8 @@ 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)