Commit b7fb00d3 authored by Zi Yan's avatar Zi Yan Committed by Tong Tiangen
Browse files

memory tiering: read last_cpupid correctly in do_huge_pmd_numa_page()

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/?id=3eb2091c653480e02e9c2a114c4725ec654bca63

--------------------------------

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: 33024536 ("memory tiering: hot page selection with hint page fault latency")
Signed-off-by: default avatarZi Yan <ziy@nvidia.com>
Reported-by: default avatarDavid Hildenbrand <david@redhat.com>
Closes: https://lore.kernel.org/linux-mm/9af34a6b-ca56-4a64-8aa6-ade65f109288@redhat.com/


Reviewed-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Reviewed-by: default avatarBaolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Conflicts:
	mm/huge_memory.c
[context conflicts, not affect.]
Signed-off-by: default avatarTong Tiangen <tongtiangen@huawei.com>
parent 3b393e43
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+2 −1
Original line number Diff line number Diff line
@@ -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) {