From: Zi Yan <ziy@nvidia.com> mainline inclusion from mainline-v6.12-rc1 commit 3eb2091c653480e02e9c2a114c4725ec654bca63 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IB8EOE Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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 <ziy@nvidia.com> Reported-by: David Hildenbrand <david@redhat.com> Closes: https://lore.kernel.org/linux-mm/9af34a6b-ca56-4a64-8aa6-ade65f109288@redhat... Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Conflicts: mm/huge_memory.c [context conflicts, not affect.] Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> --- 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 6bb149f9e617..2b32eb773481 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2033,7 +2033,8 @@ 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, vma, haddr, nid, &flags); if (target_nid == NUMA_NO_NODE) { -- 2.25.1