* [PATCH 1/2] mm: remove pagetable_dtor_free()
2026-10-30 8:37 [PATCH 0/2] mm: Remove pagetable_dtor_free() Muchun Song
@ 2026-10-30 8:37 ` Muchun Song
2026-10-30 9:39 ` Geert Uytterhoeven
2026-10-30 8:38 ` [PATCH 2/2] mm: remove redundant pagetable_dtor() calls Muchun Song
2026-10-30 13:48 ` [PATCH 0/2] mm: Remove pagetable_dtor_free() Vishal Moola (Fractile)
2 siblings, 1 reply; 6+ messages in thread
From: Muchun Song @ 2026-10-30 8:37 UTC (permalink / raw)
To: Andrew Morton
Cc: David Hildenbrand, Oscar Salvador, Alistair Popple, Will Deacon,
Aneesh Kumar K . V, Arnd Bergmann, Geert Uytterhoeven,
Madhavan Srinivasan, Alexander Gordeev, Gerald Schaefer,
Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz,
David S . Miller, Andreas Larsson, Dave Hansen, x86, linux-m68k,
linuxppc-dev, linux-s390, linux-sh, sparclinux, linux-arch,
linux-mm, linux-kernel, Muchun Song, Muchun Song
pagetable_free() now runs pagetable_dtor() for pages that have gone
through a page-table constructor, so pagetable_dtor_free() no longer
provides distinct behavior.
Use pagetable_free() directly at the remaining call sites and remove
the redundant helper. This keeps the decision to run the destructor in
the common free path.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
arch/m68k/include/asm/mcf_pgalloc.h | 4 ++--
arch/m68k/mm/motorola.c | 2 +-
arch/s390/mm/pgalloc.c | 4 ++--
arch/sh/mm/pgtable.c | 2 +-
arch/x86/mm/pat/set_memory.c | 10 +---------
arch/x86/mm/pgtable.c | 4 ++--
include/asm-generic/pgalloc.h | 12 ++++++------
include/asm-generic/tlb.h | 2 +-
include/linux/mm.h | 6 ------
9 files changed, 16 insertions(+), 30 deletions(-)
diff --git a/arch/m68k/include/asm/mcf_pgalloc.h b/arch/m68k/include/asm/mcf_pgalloc.h
index b53ff0950db2..27c3b91ac0b8 100644
--- a/arch/m68k/include/asm/mcf_pgalloc.h
+++ b/arch/m68k/include/asm/mcf_pgalloc.h
@@ -7,7 +7,7 @@
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
- pagetable_dtor_free(virt_to_ptdesc(pte));
+ pagetable_free(virt_to_ptdesc(pte));
}
extern const char bad_pmd_string[];
@@ -74,7 +74,7 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
- pagetable_dtor_free(virt_to_ptdesc(pgd));
+ pagetable_free(virt_to_ptdesc(pgd));
}
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index f3efa0d13963..d4ad3ccb13b6 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c
@@ -237,7 +237,7 @@ int free_pointer_table(void *table, int type)
spin_unlock_bh(&ptable_lock);
mmu_page_dtor((void *)pt_addr);
- pagetable_dtor_free(virt_to_ptdesc((void *)pt_addr));
+ pagetable_free(virt_to_ptdesc((void *)pt_addr));
return 1;
} else if (ptable_list[type].next != dp) {
/*
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index 4b160eedc5a0..1b7061498adc 100644
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -125,7 +125,7 @@ void page_table_free(struct mm_struct *mm, unsigned long *table)
if (pagetable_is_reserved(ptdesc))
return free_reserved_ptdesc(ptdesc);
- pagetable_dtor_free(ptdesc);
+ pagetable_free(ptdesc);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -133,7 +133,7 @@ static void pte_free_now(struct rcu_head *head)
{
struct ptdesc *ptdesc = container_of(head, struct ptdesc, pt_rcu_head);
- pagetable_dtor_free(ptdesc);
+ pagetable_free(ptdesc);
}
void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable)
diff --git a/arch/sh/mm/pgtable.c b/arch/sh/mm/pgtable.c
index f6184b86b89c..810730795358 100644
--- a/arch/sh/mm/pgtable.c
+++ b/arch/sh/mm/pgtable.c
@@ -64,7 +64,7 @@ static void __tlb_remove_table_slab(void *table)
static void __tlb_remove_table_pgtable(void *table)
{
- pagetable_dtor_free(table);
+ pagetable_free(table);
}
void __tlb_remove_table(void *table)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index b1d5c5a0ffb4..98c0a0d29769 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -441,15 +441,7 @@ static void __cpa_collapse_large_pages(struct cpa_data *cpa)
list_for_each_entry_safe(ptdesc, tmp, &pgtables, pt_list) {
list_del(&ptdesc->pt_list);
- /*
- * Only early alloc'd direct map should not be flagged PG_table
- * here and those shouldn't be collapsed. However be abundantly
- * cautious and handle the !PG_table case too.
- */
- if (PageTable((ptdesc_page(ptdesc))))
- pagetable_dtor_free(ptdesc);
- else
- pagetable_free(ptdesc);
+ pagetable_free(ptdesc);
}
}
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 4a105f283cfb..81b3bb9a197a 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -732,7 +732,7 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr)
for (i = 0; i < PTRS_PER_PMD; i++) {
if (!pmd_none(pmd[i])) {
pt = page_ptdesc(pmd_page(pmd[i]));
- pagetable_dtor_free(pt);
+ pagetable_free(pt);
}
}
@@ -759,7 +759,7 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
/* INVLPG to clear all paging-structure caches */
flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
- pagetable_dtor_free(pt);
+ pagetable_free(pt);
return 1;
}
diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h
index 051aa1331051..0ba651c1336d 100644
--- a/include/asm-generic/pgalloc.h
+++ b/include/asm-generic/pgalloc.h
@@ -54,7 +54,7 @@ static inline pte_t *pte_alloc_one_kernel_noprof(struct mm_struct *mm)
*/
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
- pagetable_dtor_free(virt_to_ptdesc(pte));
+ pagetable_free(virt_to_ptdesc(pte));
}
/**
@@ -115,7 +115,7 @@ static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
{
struct ptdesc *ptdesc = page_ptdesc(pte_page);
- pagetable_dtor_free(ptdesc);
+ pagetable_free(ptdesc);
}
@@ -162,7 +162,7 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
struct ptdesc *ptdesc = virt_to_ptdesc(pmd);
BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
- pagetable_dtor_free(ptdesc);
+ pagetable_free(ptdesc);
}
#endif
@@ -213,7 +213,7 @@ static inline void __pud_free(struct mm_struct *mm, pud_t *pud)
struct ptdesc *ptdesc = virt_to_ptdesc(pud);
BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
- pagetable_dtor_free(ptdesc);
+ pagetable_free(ptdesc);
}
#ifndef __HAVE_ARCH_PUD_FREE
@@ -261,7 +261,7 @@ static inline void __p4d_free(struct mm_struct *mm, p4d_t *p4d)
struct ptdesc *ptdesc = virt_to_ptdesc(p4d);
BUG_ON((unsigned long)p4d & (PAGE_SIZE-1));
- pagetable_dtor_free(ptdesc);
+ pagetable_free(ptdesc);
}
#ifndef __HAVE_ARCH_P4D_FREE
@@ -300,7 +300,7 @@ static inline void __pgd_free(struct mm_struct *mm, pgd_t *pgd)
struct ptdesc *ptdesc = virt_to_ptdesc(pgd);
BUG_ON((unsigned long)pgd & (PAGE_SIZE-1));
- pagetable_dtor_free(ptdesc);
+ pagetable_free(ptdesc);
}
#ifndef __HAVE_ARCH_PGD_FREE
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index fbe1114e9a44..b38b262bff5f 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -202,7 +202,7 @@ static inline void __tlb_remove_table(void *table)
{
struct ptdesc *ptdesc = (struct ptdesc *)table;
- pagetable_dtor_free(ptdesc);
+ pagetable_free(ptdesc);
}
#endif
diff --git a/include/linux/mm.h b/include/linux/mm.h
index cb993a1d0728..26b1ad5998d9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4083,12 +4083,6 @@ static inline void pagetable_free(struct ptdesc *pt)
}
}
-static inline void pagetable_dtor_free(struct ptdesc *ptdesc)
-{
- pagetable_dtor(ptdesc);
- pagetable_free(ptdesc);
-}
-
static inline bool pagetable_pte_ctor(struct mm_struct *mm,
struct ptdesc *ptdesc)
{
--
2.54.0
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 1/2] mm: remove pagetable_dtor_free()
2026-10-30 8:37 ` [PATCH 1/2] mm: remove pagetable_dtor_free() Muchun Song
@ 2026-10-30 9:39 ` Geert Uytterhoeven
0 siblings, 0 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2026-10-30 9:39 UTC (permalink / raw)
To: Muchun Song
Cc: Andrew Morton, David Hildenbrand, Oscar Salvador,
Alistair Popple, Will Deacon, Aneesh Kumar K . V, Arnd Bergmann,
Madhavan Srinivasan, Alexander Gordeev, Gerald Schaefer,
Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz,
David S . Miller, Andreas Larsson, Dave Hansen, x86, linux-m68k,
linuxppc-dev, linux-s390, linux-sh, sparclinux, linux-arch,
linux-mm, linux-kernel, Muchun Song
On Fri, 30 Oct 2026 at 09:38, Muchun Song <songmuchun@bytedance.com> wrote:
> pagetable_free() now runs pagetable_dtor() for pages that have gone
> through a page-table constructor, so pagetable_dtor_free() no longer
> provides distinct behavior.
>
> Use pagetable_free() directly at the remaining call sites and remove
> the redundant helper. This keeps the decision to run the destructor in
> the common free path.
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> ---
> arch/m68k/include/asm/mcf_pgalloc.h | 4 ++--
> arch/m68k/mm/motorola.c | 2 +-
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/2] mm: remove redundant pagetable_dtor() calls
2026-10-30 8:37 [PATCH 0/2] mm: Remove pagetable_dtor_free() Muchun Song
2026-10-30 8:37 ` [PATCH 1/2] mm: remove pagetable_dtor_free() Muchun Song
@ 2026-10-30 8:38 ` Muchun Song
2026-10-30 9:39 ` Geert Uytterhoeven
2026-10-30 13:48 ` [PATCH 0/2] mm: Remove pagetable_dtor_free() Vishal Moola (Fractile)
2 siblings, 1 reply; 6+ messages in thread
From: Muchun Song @ 2026-10-30 8:38 UTC (permalink / raw)
To: Andrew Morton
Cc: David Hildenbrand, Oscar Salvador, Alistair Popple, Will Deacon,
Aneesh Kumar K . V, Arnd Bergmann, Geert Uytterhoeven,
Madhavan Srinivasan, Alexander Gordeev, Gerald Schaefer,
Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz,
David S . Miller, Andreas Larsson, Dave Hansen, x86, linux-m68k,
linuxppc-dev, linux-s390, linux-sh, sparclinux, linux-arch,
linux-mm, linux-kernel, Muchun Song, Muchun Song
pagetable_free() now runs pagetable_dtor() for constructed page
tables. Calling the destructor immediately before freeing the page table
therefore duplicates the lifecycle handling at each caller.
Remove the redundant calls and let pagetable_free() handle the
destructor. No functional change is intended.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
arch/m68k/include/asm/mcf_pgalloc.h | 1 -
arch/powerpc/mm/book3s64/mmu_context.c | 1 -
arch/powerpc/mm/book3s64/pgtable.c | 1 -
arch/powerpc/mm/pgtable-frag.c | 2 --
arch/s390/include/asm/pgalloc.h | 4 ----
arch/sparc/mm/init_64.c | 1 -
arch/x86/mm/pgtable.c | 1 -
7 files changed, 11 deletions(-)
diff --git a/arch/m68k/include/asm/mcf_pgalloc.h b/arch/m68k/include/asm/mcf_pgalloc.h
index 27c3b91ac0b8..f607d239ce16 100644
--- a/arch/m68k/include/asm/mcf_pgalloc.h
+++ b/arch/m68k/include/asm/mcf_pgalloc.h
@@ -62,7 +62,6 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
{
struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);
- pagetable_dtor(ptdesc);
pagetable_free(ptdesc);
}
diff --git a/arch/powerpc/mm/book3s64/mmu_context.c b/arch/powerpc/mm/book3s64/mmu_context.c
index 2fe787e6c2dc..36ce18e625cc 100644
--- a/arch/powerpc/mm/book3s64/mmu_context.c
+++ b/arch/powerpc/mm/book3s64/mmu_context.c
@@ -249,7 +249,6 @@ static void pmd_frag_destroy(void *pmd_frag)
count = ((unsigned long)pmd_frag & ~PAGE_MASK) >> PMD_FRAG_SIZE_SHIFT;
/* We allow PTE_FRAG_NR fragments from a PTE page */
if (atomic_sub_and_test(PMD_FRAG_NR - count, &ptdesc->pt_frag_refcount)) {
- pagetable_dtor(ptdesc);
pagetable_free(ptdesc);
}
}
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 85ab6723c8f2..4ff471775f2d 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -450,7 +450,6 @@ void pmd_fragment_free(unsigned long *pmd)
BUG_ON(atomic_read(&ptdesc->pt_frag_refcount) <= 0);
if (atomic_dec_and_test(&ptdesc->pt_frag_refcount)) {
- pagetable_dtor(ptdesc);
pagetable_free(ptdesc);
}
}
diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
index ae742564a3d5..2568bb514181 100644
--- a/arch/powerpc/mm/pgtable-frag.c
+++ b/arch/powerpc/mm/pgtable-frag.c
@@ -26,7 +26,6 @@ void pte_frag_destroy(void *pte_frag)
/* We allow PTE_FRAG_NR fragments from a PTE page */
if (atomic_sub_and_test(PTE_FRAG_NR - count, &ptdesc->pt_frag_refcount)) {
folio_clear_active(ptdesc_folio(ptdesc));
- pagetable_dtor(ptdesc);
pagetable_free(ptdesc);
}
}
@@ -110,7 +109,6 @@ static void pte_free_now(struct rcu_head *head)
struct ptdesc *ptdesc;
ptdesc = container_of(head, struct ptdesc, pt_rcu_head);
- pagetable_dtor(ptdesc);
pagetable_free(ptdesc);
}
diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
index a5de9e61ea9e..d554c475c61f 100644
--- a/arch/s390/include/asm/pgalloc.h
+++ b/arch/s390/include/asm/pgalloc.h
@@ -66,7 +66,6 @@ static inline void p4d_free(struct mm_struct *mm, p4d_t *p4d)
if (mm_p4d_folded(mm))
return;
- pagetable_dtor(virt_to_ptdesc(p4d));
crst_table_free(mm, (unsigned long *) p4d);
}
@@ -88,7 +87,6 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud)
if (mm_pud_folded(mm))
return;
- pagetable_dtor(virt_to_ptdesc(pud));
crst_table_free(mm, (unsigned long *) pud);
}
@@ -111,7 +109,6 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
{
if (mm_pmd_folded(mm))
return;
- pagetable_dtor(virt_to_ptdesc(pmd));
crst_table_free(mm, (unsigned long *) pmd);
}
@@ -144,7 +141,6 @@ static inline pgd_t *pgd_alloc_noprof(struct mm_struct *mm)
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
- pagetable_dtor(virt_to_ptdesc(pgd));
crst_table_free(mm, (unsigned long *) pgd);
}
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 9bbccb5d23a8..9f3cb7883f3f 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2840,7 +2840,6 @@ static void __pte_free(pgtable_t pte)
{
struct ptdesc *ptdesc = virt_to_ptdesc(pte);
- pagetable_dtor(ptdesc);
pagetable_free(ptdesc);
}
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 81b3bb9a197a..9929d7d55d72 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -156,7 +156,6 @@ static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
if (pmds[i]) {
ptdesc = virt_to_ptdesc(pmds[i]);
- pagetable_dtor(ptdesc);
pagetable_free(ptdesc);
mm_dec_nr_pmds(mm);
}
--
2.54.0
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 2/2] mm: remove redundant pagetable_dtor() calls
2026-10-30 8:38 ` [PATCH 2/2] mm: remove redundant pagetable_dtor() calls Muchun Song
@ 2026-10-30 9:39 ` Geert Uytterhoeven
0 siblings, 0 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2026-10-30 9:39 UTC (permalink / raw)
To: Muchun Song
Cc: Andrew Morton, David Hildenbrand, Oscar Salvador,
Alistair Popple, Will Deacon, Aneesh Kumar K . V, Arnd Bergmann,
Madhavan Srinivasan, Alexander Gordeev, Gerald Schaefer,
Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz,
David S . Miller, Andreas Larsson, Dave Hansen, x86, linux-m68k,
linuxppc-dev, linux-s390, linux-sh, sparclinux, linux-arch,
linux-mm, linux-kernel, Muchun Song
On Fri, 30 Oct 2026 at 09:38, Muchun Song <songmuchun@bytedance.com> wrote:
> pagetable_free() now runs pagetable_dtor() for constructed page
> tables. Calling the destructor immediately before freeing the page table
> therefore duplicates the lifecycle handling at each caller.
>
> Remove the redundant calls and let pagetable_free() handle the
> destructor. No functional change is intended.
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> ---
> arch/m68k/include/asm/mcf_pgalloc.h | 1 -
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/2] mm: Remove pagetable_dtor_free()
2026-10-30 8:37 [PATCH 0/2] mm: Remove pagetable_dtor_free() Muchun Song
2026-10-30 8:37 ` [PATCH 1/2] mm: remove pagetable_dtor_free() Muchun Song
2026-10-30 8:38 ` [PATCH 2/2] mm: remove redundant pagetable_dtor() calls Muchun Song
@ 2026-10-30 13:48 ` Vishal Moola (Fractile)
2 siblings, 0 replies; 6+ messages in thread
From: Vishal Moola (Fractile) @ 2026-10-30 13:48 UTC (permalink / raw)
To: Muchun Song
Cc: Andrew Morton, David Hildenbrand, Oscar Salvador,
Alistair Popple, Will Deacon, Aneesh Kumar K . V, Arnd Bergmann,
Geert Uytterhoeven, Madhavan Srinivasan, Alexander Gordeev,
Gerald Schaefer, Yoshinori Sato, Rich Felker,
John Paul Adrian Glaubitz, David S . Miller, Andreas Larsson,
Dave Hansen, x86, linux-m68k, linuxppc-dev, linux-s390, linux-sh,
sparclinux, linux-arch, linux-mm, linux-kernel, Muchun Song
On Fri, Oct 30, 2026 at 04:37:58PM +0800, Muchun Song wrote:
> This is a follow-up cleanup to the page-table teardown fixes [1].
>
> pagetable_free() now invokes pagetable_dtor() for constructed page tables.
> This makes pagetable_dtor_free() redundant and leaves explicit destructor
> calls immediately before pagetable_free() duplicating lifecycle handling.
>
> Remove pagetable_dtor_free() and convert its callers to pagetable_free(),
> then remove the remaining redundant pagetable_dtor() calls. This keeps the
> destructor decision in the common free path. No functional change is
> intended.
>
> [1] https://lore.kernel.org/r/20261023063428.3658761-1-songmuchun@bytedance.com
>
> Muchun Song (2):
> mm: remove pagetable_dtor_free()
> mm: remove redundant pagetable_dtor() calls
For the series:
Acked-by: Vishal Moola (Fractile) <vishal.moola@gmail.com>
^ permalink raw reply [flat|nested] 6+ messages in thread