[PATCH v3 04/22] perf/events: replace READ_ONCE() with standard page table accessors

From: Samuel Holland

Date: Wed Nov 12 2025 - 20:47:05 EST


From: Anshuman Khandual <anshuman.khandual@xxxxxxx>

Replace READ_ONCE() with standard page table accessors i.e pxdp_get() which
anyways default into READ_ONCE() in cases where platform does not override.

Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: linux-perf-users@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Link: https://lore.kernel.org/r/20251006042622.1743675-1-anshuman.khandual@xxxxxxx/
Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
---

Changes in v3:
- Replace my patch with Anshuman Khandual's patch from LKML

Changes in v2:
- New patch for v2

kernel/events/core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1fd347da9026..fa4f9165bd94 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8122,7 +8122,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
pte_t *ptep, pte;

pgdp = pgd_offset(mm, addr);
- pgd = READ_ONCE(*pgdp);
+ pgd = pgdp_get(pgdp);
if (pgd_none(pgd))
return 0;

@@ -8130,7 +8130,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
return pgd_leaf_size(pgd);

p4dp = p4d_offset_lockless(pgdp, pgd, addr);
- p4d = READ_ONCE(*p4dp);
+ p4d = p4dp_get(p4dp);
if (!p4d_present(p4d))
return 0;

@@ -8138,7 +8138,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
return p4d_leaf_size(p4d);

pudp = pud_offset_lockless(p4dp, p4d, addr);
- pud = READ_ONCE(*pudp);
+ pud = pudp_get(pudp);
if (!pud_present(pud))
return 0;

--
2.47.2