* [PATCH v9 01/10] arm64/mm: add pte_set_huge() and pte_clear_huge()
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 21:30 ` Barry Song
2026-09-23 6:28 ` [PATCH v9 02/10] powerpc/8xx: add pte_set_huge() Wen Jiang
` (8 subsequent siblings)
9 siblings, 1 reply; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
vmap installs PTE-level block mappings (PTE_CONT on arm64) by reusing
set_huge_pte_at() and huge_ptep_get_and_clear(), which are HugeTLB
helpers gated by CONFIG_HUGETLB_PAGE. This makes the feature silently
unavailable on CONFIG_HUGETLB_PAGE=n kernels and couples mm/vmalloc.c to
HugeTLB internals it does not otherwise need.
Add pte_set_huge()/pte_clear_huge() to arm64, joining the existing
pmd_set_huge()/pud_set_huge() family in mm/mmu.c. They build on
__set_ptes() and __get_and_clear_full_ptes() directly, so they do not
depend on CONFIG_HUGETLB_PAGE.
There is no caller yet: mm/vmalloc.c is converted later in this series,
once the generic fallbacks are in place.
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
---
arch/arm64/include/asm/pgtable.h | 6 ++++++
arch/arm64/mm/mmu.c | 20 ++++++++++++++++++++
2 files changed, 26 insertions(+)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 6000905a2e865..9b762eb68cff0 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -1978,6 +1978,12 @@ static inline void clear_young_dirty_ptes(struct vm_area_struct *vma,
#endif /* CONFIG_ARM64_CONTPTE */
+#define __HAVE_ARCH_PTE_SET_HUGE
+void pte_set_huge(pte_t *ptep, unsigned long addr, phys_addr_t phys,
+ pgprot_t prot, unsigned long size);
+#define __HAVE_ARCH_PTE_CLEAR_HUGE
+pte_t pte_clear_huge(pte_t *ptep, unsigned long addr, unsigned long size);
+
#endif /* !__ASSEMBLER__ */
#endif /* __ASM_PGTABLE_H */
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 79d90226fd5dc..4a3d084bb7556 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1912,6 +1912,26 @@ int pmd_clear_huge(pmd_t *pmdp)
return 1;
}
+void pte_set_huge(pte_t *ptep, unsigned long addr, phys_addr_t phys,
+ pgprot_t prot, unsigned long size)
+{
+ unsigned long pfn = __phys_to_pfn(phys);
+ pte_t pte = pte_mkcont(pfn_pte(pfn, prot));
+ unsigned int nr = size >> PAGE_SHIFT;
+
+ VM_WARN_ON(!IS_ALIGNED(size, CONT_PTE_SIZE));
+ VM_WARN_ON(!IS_ALIGNED(addr, CONT_PTE_SIZE));
+ VM_WARN_ON(!IS_ALIGNED(pfn, CONT_PTES));
+
+ __set_ptes(&init_mm, addr, ptep, pte, nr);
+}
+
+pte_t pte_clear_huge(pte_t *ptep, unsigned long addr, unsigned long size)
+{
+ return __get_and_clear_full_ptes(&init_mm, addr, ptep,
+ size >> PAGE_SHIFT, 0);
+}
+
int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
{
pte_t *table;
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH v9 01/10] arm64/mm: add pte_set_huge() and pte_clear_huge()
2026-09-23 6:28 ` [PATCH v9 01/10] arm64/mm: add pte_set_huge() and pte_clear_huge() Wen Jiang
@ 2026-09-23 21:30 ` Barry Song
0 siblings, 0 replies; 15+ messages in thread
From: Barry Song @ 2026-09-23 21:30 UTC (permalink / raw)
To: Wen Jiang
Cc: akpm, catalin.marinas, linux-mm, urezki, will, Xueyuan.chen21,
ajd, anshuman.khandual, chleroy, david, dev.jain, jiangwen6,
leo.yan, linux-arm-kernel, linux-kernel, linuxppc-dev, maddy,
mpe, npiggin, rppt, ryan.roberts
On Wed, Sep 23, 2026 at 2:28 PM Wen Jiang <jiangwenxiaomi@gmail.com> wrote:
>
> vmap installs PTE-level block mappings (PTE_CONT on arm64) by reusing
> set_huge_pte_at() and huge_ptep_get_and_clear(), which are HugeTLB
> helpers gated by CONFIG_HUGETLB_PAGE. This makes the feature silently
> unavailable on CONFIG_HUGETLB_PAGE=n kernels and couples mm/vmalloc.c to
> HugeTLB internals it does not otherwise need.
>
> Add pte_set_huge()/pte_clear_huge() to arm64, joining the existing
> pmd_set_huge()/pud_set_huge() family in mm/mmu.c. They build on
> __set_ptes() and __get_and_clear_full_ptes() directly, so they do not
> depend on CONFIG_HUGETLB_PAGE.
>
> There is no caller yet: mm/vmalloc.c is converted later in this series,
> once the generic fallbacks are in place.
>
> Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
LGTM. Please see the comment below.
Reviewed-by: Barry Song <baohua@kernel.org>
[...]
> +void pte_set_huge(pte_t *ptep, unsigned long addr, phys_addr_t phys,
> + pgprot_t prot, unsigned long size)
> +{
> + unsigned long pfn = __phys_to_pfn(phys);
> + pte_t pte = pte_mkcont(pfn_pte(pfn, prot));
> + unsigned int nr = size >> PAGE_SHIFT;
> +
> + VM_WARN_ON(!IS_ALIGNED(size, CONT_PTE_SIZE));
> + VM_WARN_ON(!IS_ALIGNED(addr, CONT_PTE_SIZE));
> + VM_WARN_ON(!IS_ALIGNED(pfn, CONT_PTES));
> +
> + __set_ptes(&init_mm, addr, ptep, pte, nr);
You have patch 4 to revert the `clear_flush()` modification from
06fc959fcff ("arm64/mm: Support huge pte-mapped pages in vmap").
I guess you may still need to guard against the case I mentioned in my
reply to patch 4:
https://lore.kernel.org/linux-mm/CAGsJ_4xiLScr2PrPu7Eem73GvPCtsuYd3J05kW3SC4QSs5Q4aQ@mail.gmail.com/
Something like this:
VM_WARN_ON (pte_valid(__ptep_get(ptep)));
Best Regards
Barry
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v9 02/10] powerpc/8xx: add pte_set_huge()
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
2026-09-23 6:28 ` [PATCH v9 01/10] arm64/mm: add pte_set_huge() and pte_clear_huge() Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 6:28 ` [PATCH v9 03/10] mm/vmalloc: use pte_set_huge()/pte_clear_huge() for PTE-level block mappings Wen Jiang
` (7 subsequent siblings)
9 siblings, 0 replies; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
vmap installs PTE-level block mappings (SZ_16K/SZ_512K on powerpc/8xx)
by reusing set_huge_pte_at(), a HugeTLB helper gated by
CONFIG_HUGETLB_PAGE. This makes the feature silently unavailable on
CONFIG_HUGETLB_PAGE=n kernels and couples mm/vmalloc.c to HugeTLB
internals it does not otherwise need.
Add pte_set_huge() to powerpc/8xx, next to the existing
pmd_clear_huge()/pud_clear_huge() in mm/nohash/8xx.c. It builds the huge
PTE and writes it into the backing cells directly, without going through
set_huge_pte_at(), so it does not depend on CONFIG_HUGETLB_PAGE.
No pte_clear_huge() is needed: 8xx does not implement
arch_vmap_pte_range_unmap_size(), so the vmap unmap path never takes the
PTE-clearing branch.
In practice PPC_8xx selects HUGETLBFS unconditionally, so
CONFIG_HUGETLB_PAGE=n does not occur there today; this is a decoupling
cleanup rather than a new configuration.
There is no caller yet: mm/vmalloc.c is converted later in this series,
once the generic fallbacks are in place.
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
---
arch/powerpc/include/asm/nohash/32/pte-8xx.h | 4 +++
arch/powerpc/mm/nohash/8xx.c | 29 ++++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
index e2ea8ba9f8cae..1ee3f8f0de974 100644
--- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
@@ -235,6 +235,10 @@ static inline pte_t ptep_get(pte_t *ptep)
}
#endif /* CONFIG_PPC_16K_PAGES */
+#define __HAVE_ARCH_PTE_SET_HUGE
+void pte_set_huge(pte_t *ptep, unsigned long addr, phys_addr_t phys,
+ pgprot_t prot, unsigned long size);
+
#endif
#endif /* __KERNEL__ */
diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
index a9d3f4729eada..2518d2a6bdb41 100644
--- a/arch/powerpc/mm/nohash/8xx.c
+++ b/arch/powerpc/mm/nohash/8xx.c
@@ -220,3 +220,32 @@ int pmd_clear_huge(pmd_t *pmd)
{
return 0;
}
+
+/*
+ * vmap PTE-level block mapping. Sets a present kernel mapping directly,
+ * so unlike set_huge_pte_at() it needs neither CONFIG_HUGETLB_PAGE nor
+ * set_pte_filter() (a no-op for non-exec kernel mappings).
+ */
+void pte_set_huge(pte_t *ptep, unsigned long addr, phys_addr_t phys,
+ pgprot_t prot, unsigned long size)
+{
+ pmd_t *pmdp = pmd_off(&init_mm, addr);
+ pte_t pte = pfn_pte(PHYS_PFN(phys), prot);
+ pte_basic_t val;
+ pte_basic_t *entry = (pte_basic_t *)ptep;
+ int num, i;
+
+ pte = arch_make_huge_pte(pte, ilog2(size), 0);
+ val = pte_val(pte);
+
+ /*
+ * Make sure hardware valid bit is not set. We don't do
+ * tlb flush for this update.
+ */
+ VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
+
+ num = number_of_cells_per_pte(pmdp, val, 1);
+
+ for (i = 0; i < num; i++, entry++, val += SZ_4K)
+ *entry = val;
+}
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* [PATCH v9 03/10] mm/vmalloc: use pte_set_huge()/pte_clear_huge() for PTE-level block mappings
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
2026-09-23 6:28 ` [PATCH v9 01/10] arm64/mm: add pte_set_huge() and pte_clear_huge() Wen Jiang
2026-09-23 6:28 ` [PATCH v9 02/10] powerpc/8xx: add pte_set_huge() Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 21:38 ` Barry Song
2026-09-23 6:28 ` [PATCH v9 04/10] arm64/hugetlb: drop the init_mm special case in clear_flush() Wen Jiang
` (6 subsequent siblings)
9 siblings, 1 reply; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
vmap installs PTE-level block mappings by reusing set_huge_pte_at() and
huge_ptep_get_and_clear() under #ifdef CONFIG_HUGETLB_PAGE. This makes
the feature silently unavailable on CONFIG_HUGETLB_PAGE=n kernels and
couples mm/vmalloc.c to HugeTLB internals it does not otherwise need.
Now that arm64 and powerpc/8xx provide pte_set_huge() and
pte_clear_huge(), add the generic fallbacks next to the existing
pmd/pud_set_huge() family and convert vmap_pte_range() and
vunmap_pte_range() to the new helpers. The CONFIG_HUGETLB_PAGE guards
around the block-mapping paths are dropped, so PTE-level block mappings
now also work on CONFIG_HUGETLB_PAGE=n kernels, and mm/vmalloc.c no
longer includes <linux/hugetlb.h>.
The fallbacks exist only to keep the build working on architectures
without PTE-level block mapping support. They are unreachable there:
the callers only run when arch_vmap_pte_range_map_size() or
arch_vmap_pte_range_unmap_size() return a size other than PAGE_SIZE,
which requires an arch implementation. BUILD_BUG() makes that
explicit rather than silently doing nothing.
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
---
include/linux/pgtable.h | 29 +++++++++++++++++++++++++++++
mm/vmalloc.c | 19 ++++++-------------
2 files changed, 35 insertions(+), 13 deletions(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 8c093c119e5a8..a7fd51fec8a17 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -2204,6 +2204,35 @@ static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
}
#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+/*
+ * PTE-level block mappings for vmap.
+ *
+ * pte_set_huge() only has to be implemented by architectures whose
+ * arch_vmap_pte_range_map_size() can return a size other than PAGE_SIZE.
+ */
+#ifndef __HAVE_ARCH_PTE_SET_HUGE
+static inline void pte_set_huge(pte_t *ptep, unsigned long addr,
+ phys_addr_t phys, pgprot_t prot,
+ unsigned long size)
+{
+ BUILD_BUG();
+}
+#endif
+
+/*
+ * Likewise, pte_clear_huge() only has to be implemented by architectures
+ * whose arch_vmap_pte_range_unmap_size() can return a size other than
+ * PAGE_SIZE.
+ */
+#ifndef __HAVE_ARCH_PTE_CLEAR_HUGE
+static inline pte_t pte_clear_huge(pte_t *ptep, unsigned long addr,
+ unsigned long size)
+{
+ BUILD_BUG();
+ return __pte(0);
+}
+#endif
+
#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index bea9f76ed7e74..fb757d95bde25 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -38,7 +38,6 @@
#include <linux/rbtree_augmented.h>
#include <linux/overflow.h>
#include <linux/pgtable.h>
-#include <linux/hugetlb.h>
#include <linux/sched/mm.h>
#include <asm/tlbflush.h>
#include <asm/shmparam.h>
@@ -100,7 +99,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
pte_t *pte;
u64 pfn;
struct page *page;
- unsigned long size = PAGE_SIZE;
+ unsigned long size;
if (WARN_ON_ONCE(!PAGE_ALIGNED(end - addr)))
return -EINVAL;
@@ -121,17 +120,12 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
BUG();
}
-#ifdef CONFIG_HUGETLB_PAGE
size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
if (size != PAGE_SIZE) {
- pte_t entry = pfn_pte(pfn, prot);
-
- entry = arch_make_huge_pte(entry, ilog2(size), 0);
- set_huge_pte_at(&init_mm, addr, pte, entry, size);
+ pte_set_huge(pte, addr, PFN_PHYS(pfn), prot, size);
pfn += PFN_DOWN(size);
continue;
}
-#endif
set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
pfn++;
} while (pte += PFN_DOWN(size), addr += size, addr != end);
@@ -391,25 +385,24 @@ static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
{
pte_t *pte;
pte_t ptent;
- unsigned long size = PAGE_SIZE;
+ unsigned long size;
pte = pte_offset_kernel(pmd, addr);
lazy_mmu_mode_enable();
do {
-#ifdef CONFIG_HUGETLB_PAGE
size = arch_vmap_pte_range_unmap_size(addr, pte);
if (size != PAGE_SIZE) {
if (WARN_ON(!IS_ALIGNED(addr, size))) {
addr = ALIGN_DOWN(addr, size);
pte = PTR_ALIGN_DOWN(pte, sizeof(*pte) * (size >> PAGE_SHIFT));
}
- ptent = huge_ptep_get_and_clear(&init_mm, addr, pte, size);
+ ptent = pte_clear_huge(pte, addr, size);
if (WARN_ON(end - addr < size))
size = end - addr;
- } else
-#endif
+ } else {
ptent = ptep_get_and_clear(&init_mm, addr, pte);
+ }
WARN_ON(!pte_none(ptent) && !pte_present(ptent));
} while (pte += (size >> PAGE_SHIFT), addr += size, addr != end);
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH v9 03/10] mm/vmalloc: use pte_set_huge()/pte_clear_huge() for PTE-level block mappings
2026-09-23 6:28 ` [PATCH v9 03/10] mm/vmalloc: use pte_set_huge()/pte_clear_huge() for PTE-level block mappings Wen Jiang
@ 2026-09-23 21:38 ` Barry Song
2026-09-23 21:57 ` Christophe Leroy (CS GROUP)
0 siblings, 1 reply; 15+ messages in thread
From: Barry Song @ 2026-09-23 21:38 UTC (permalink / raw)
To: Wen Jiang
Cc: akpm, catalin.marinas, linux-mm, urezki, will, Xueyuan.chen21,
ajd, anshuman.khandual, chleroy, david, dev.jain, jiangwen6,
leo.yan, linux-arm-kernel, linux-kernel, linuxppc-dev, maddy,
mpe, npiggin, rppt, ryan.roberts
On Wed, Sep 23, 2026 at 2:28 PM Wen Jiang <jiangwenxiaomi@gmail.com> wrote:
>
> vmap installs PTE-level block mappings by reusing set_huge_pte_at() and
> huge_ptep_get_and_clear() under #ifdef CONFIG_HUGETLB_PAGE. This makes
> the feature silently unavailable on CONFIG_HUGETLB_PAGE=n kernels and
> couples mm/vmalloc.c to HugeTLB internals it does not otherwise need.
>
> Now that arm64 and powerpc/8xx provide pte_set_huge() and
> pte_clear_huge(), add the generic fallbacks next to the existing
> pmd/pud_set_huge() family and convert vmap_pte_range() and
> vunmap_pte_range() to the new helpers. The CONFIG_HUGETLB_PAGE guards
> around the block-mapping paths are dropped, so PTE-level block mappings
> now also work on CONFIG_HUGETLB_PAGE=n kernels, and mm/vmalloc.c no
> longer includes <linux/hugetlb.h>.
>
> The fallbacks exist only to keep the build working on architectures
> without PTE-level block mapping support. They are unreachable there:
Since this is a `BUILD_BUG`, can the compiler simply eliminate the call?
I guess the build would still pass even without the fallbacks, so this is
more of a build-time check than something needed to keep the build passing?
Am I missing something?
> the callers only run when arch_vmap_pte_range_map_size() or
> arch_vmap_pte_range_unmap_size() return a size other than PAGE_SIZE,
> which requires an arch implementation. BUILD_BUG() makes that
> explicit rather than silently doing nothing.
>
> Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Nice to see that `#ifdef CONFIG_HUGETLB_PAGE` and
`#include <linux/hugetlb.h>` are no longer needed in `vmalloc`.
Nothing concerns me except for the changelog issue mentioned above.
Please double-check whether the changelog needs to be corrected.
Reviewed-by: Barry Song <baohua@kernel.org>
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH v9 03/10] mm/vmalloc: use pte_set_huge()/pte_clear_huge() for PTE-level block mappings
2026-09-23 21:38 ` Barry Song
@ 2026-09-23 21:57 ` Christophe Leroy (CS GROUP)
0 siblings, 0 replies; 15+ messages in thread
From: Christophe Leroy (CS GROUP) @ 2026-09-23 21:57 UTC (permalink / raw)
To: Barry Song, Wen Jiang
Cc: akpm, catalin.marinas, linux-mm, urezki, will, Xueyuan.chen21,
ajd, anshuman.khandual, david, dev.jain, jiangwen6, leo.yan,
linux-arm-kernel, linux-kernel, linuxppc-dev, maddy, mpe,
npiggin, rppt, ryan.roberts
Le 23/09/2026 à 23:38, Barry Song a écrit :
> On Wed, Sep 23, 2026 at 2:28 PM Wen Jiang <jiangwenxiaomi@gmail.com> wrote:
>>
>> vmap installs PTE-level block mappings by reusing set_huge_pte_at() and
>> huge_ptep_get_and_clear() under #ifdef CONFIG_HUGETLB_PAGE. This makes
>> the feature silently unavailable on CONFIG_HUGETLB_PAGE=n kernels and
>> couples mm/vmalloc.c to HugeTLB internals it does not otherwise need.
>>
>> Now that arm64 and powerpc/8xx provide pte_set_huge() and
>> pte_clear_huge(), add the generic fallbacks next to the existing
>> pmd/pud_set_huge() family and convert vmap_pte_range() and
>> vunmap_pte_range() to the new helpers. The CONFIG_HUGETLB_PAGE guards
>> around the block-mapping paths are dropped, so PTE-level block mappings
>> now also work on CONFIG_HUGETLB_PAGE=n kernels, and mm/vmalloc.c no
>> longer includes <linux/hugetlb.h>.
>>
>> The fallbacks exist only to keep the build working on architectures
>> without PTE-level block mapping support. They are unreachable there:
>
> Since this is a `BUILD_BUG`, can the compiler simply eliminate the call?
> I guess the build would still pass even without the fallbacks, so this is
> more of a build-time check than something needed to keep the build passing?
Yes and that's what the compiler does, it eliminates the call.
The BUILD_BUG() is there to make sure it does eliminates the call.
The build won't pass without at least a forward declaration of the fallback.
In the old days when BUILD_BUG() didn't exist, the trick was the declare
the function and never define it. But with that trick the problem is
only detected at link time. With BUILD_BUG() the problem is detected at
build time.
>
> Am I missing something?
>
>> the callers only run when arch_vmap_pte_range_map_size() or
>> arch_vmap_pte_range_unmap_size() return a size other than PAGE_SIZE,
>> which requires an arch implementation. BUILD_BUG() makes that
>> explicit rather than silently doing nothing.
>>
>> Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
>
> Nice to see that `#ifdef CONFIG_HUGETLB_PAGE` and
> `#include <linux/hugetlb.h>` are no longer needed in `vmalloc`.
>
> Nothing concerns me except for the changelog issue mentioned above.
> Please double-check whether the changelog needs to be corrected.
>
> Reviewed-by: Barry Song <baohua@kernel.org>
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v9 04/10] arm64/hugetlb: drop the init_mm special case in clear_flush()
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
` (2 preceding siblings ...)
2026-09-23 6:28 ` [PATCH v9 03/10] mm/vmalloc: use pte_set_huge()/pte_clear_huge() for PTE-level block mappings Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 21:23 ` Barry Song
2026-09-23 6:28 ` [PATCH v9 05/10] arm64/vmalloc: allow arch_vmap_pte_range_map_size() to batch multiple CONT_PTE Wen Jiang
` (5 subsequent siblings)
9 siblings, 1 reply; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
clear_flush() calls flush_tlb_kernel_range() when mm is &init_mm. This
was added by commit 06fc959fcff7 ("arm64/mm: Support huge pte-mapped
pages in vmap") because vmap called set_huge_pte_at(&init_mm, ...).
Now that vmap uses pte_set_huge()/pte_clear_huge(), mm/vmalloc.c is no
longer a caller of set_huge_pte_at() on arm64. The only remaining
callers passing &init_mm are in arch/powerpc, which uses its own
implementation. Remove the dead branch.
No functional change.
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
---
arch/arm64/mm/hugetlbpage.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 8e799c1fe0aa6..ce247b06fe03d 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -206,10 +206,7 @@ static void clear_flush(struct mm_struct *mm,
for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
__ptep_get_and_clear_anysz(mm, addr, ptep, pgsize);
- if (mm == &init_mm)
- flush_tlb_kernel_range(saddr, addr);
- else
- __flush_hugetlb_tlb_range(&vma, saddr, addr, pgsize, TLBF_NOWALKCACHE);
+ __flush_hugetlb_tlb_range(&vma, saddr, addr, pgsize, TLBF_NOWALKCACHE);
}
void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [PATCH v9 04/10] arm64/hugetlb: drop the init_mm special case in clear_flush()
2026-09-23 6:28 ` [PATCH v9 04/10] arm64/hugetlb: drop the init_mm special case in clear_flush() Wen Jiang
@ 2026-09-23 21:23 ` Barry Song
0 siblings, 0 replies; 15+ messages in thread
From: Barry Song @ 2026-09-23 21:23 UTC (permalink / raw)
To: Wen Jiang
Cc: akpm, catalin.marinas, linux-mm, urezki, will, Xueyuan.chen21,
ajd, anshuman.khandual, chleroy, david, dev.jain, jiangwen6,
leo.yan, linux-arm-kernel, linux-kernel, linuxppc-dev, maddy,
mpe, npiggin, rppt, ryan.roberts
On Wed, Sep 23, 2026 at 2:29 PM Wen Jiang <jiangwenxiaomi@gmail.com> wrote:
>
> clear_flush() calls flush_tlb_kernel_range() when mm is &init_mm. This
> was added by commit 06fc959fcff7 ("arm64/mm: Support huge pte-mapped
> pages in vmap") because vmap called set_huge_pte_at(&init_mm, ...).
>
> Now that vmap uses pte_set_huge()/pte_clear_huge(), mm/vmalloc.c is no
> longer a caller of set_huge_pte_at() on arm64. The only remaining
> callers passing &init_mm are in arch/powerpc, which uses its own
> implementation. Remove the dead branch.
>
> No functional change.
>
> Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
LGTM. Please see the comments below.
Reviewed-by: Barry Song <baohua@kernel.org>
> ---
> arch/arm64/mm/hugetlbpage.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index 8e799c1fe0aa6..ce247b06fe03d 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -206,10 +206,7 @@ static void clear_flush(struct mm_struct *mm,
> for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
> __ptep_get_and_clear_anysz(mm, addr, ptep, pgsize);
>
> - if (mm == &init_mm)
> - flush_tlb_kernel_range(saddr, addr);
> - else
> - __flush_hugetlb_tlb_range(&vma, saddr, addr, pgsize, TLBF_NOWALKCACHE);
> + __flush_hugetlb_tlb_range(&vma, saddr, addr, pgsize, TLBF_NOWALKCACHE);
For the vmap case, we are not mapping over a valid mapping, so there is no
case where `pte_present()` can be true. But I guess we can strengthen the
check in patch 1 by adding a `VM_WARN_ON()` for `pte_valid()` and some
comments.
/* For vmap, there is no valid -> valid transition */
VM_WARN_ON (pte_valid(__ptep_get(ptep)));
Best Regards
Barry
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v9 05/10] arm64/vmalloc: allow arch_vmap_pte_range_map_size() to batch multiple CONT_PTE
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
` (3 preceding siblings ...)
2026-09-23 6:28 ` [PATCH v9 04/10] arm64/hugetlb: drop the init_mm special case in clear_flush() Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 6:28 ` [PATCH v9 06/10] mm/vmalloc: extract vmap_set_ptes() to consolidate PTE mapping logic Wen Jiang
` (4 subsequent siblings)
9 siblings, 0 replies; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
From: "Barry Song (Xiaomi)" <baohua@kernel.org>
Allow arch_vmap_pte_range_map_size to batch across multiple CONT_PTE
blocks, reducing both PTE setup and TLB flush iterations.
For CONT_PTE_SIZE-aligned ranges, return a mapping size that may cover
multiple CONT_PTE blocks, capped below PMD_SIZE. These sizes are vmalloc
mapping spans, not HugeTLB hstate sizes.
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
Tested-by: Leo Yan <leo.yan@arm.com>
---
arch/arm64/include/asm/vmalloc.h | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index 4ec1acd3c1b34..4053b1ec1902e 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h
@@ -23,10 +23,14 @@ static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr,
unsigned long end, u64 pfn,
unsigned int max_page_shift)
{
+ unsigned long size;
+
/*
* If the block is at least CONT_PTE_SIZE in size, and is naturally
* aligned in both virtual and physical space, then we can pte-map the
* block using the PTE_CONT bit for more efficient use of the TLB.
+ * The returned mapping size may cover multiple CONT_PTE_SIZE blocks,
+ * capped below PMD_SIZE.
*/
if (max_page_shift < CONT_PTE_SHIFT)
return PAGE_SIZE;
@@ -40,7 +44,9 @@ static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr,
if (!IS_ALIGNED(PFN_PHYS(pfn), CONT_PTE_SIZE))
return PAGE_SIZE;
- return CONT_PTE_SIZE;
+ size = min3(end - addr, 1UL << max_page_shift, PMD_SIZE >> 1);
+ size = round_down(size, CONT_PTE_SIZE);
+ return size;
}
#define arch_vmap_pte_range_unmap_size arch_vmap_pte_range_unmap_size
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* [PATCH v9 06/10] mm/vmalloc: extract vmap_set_ptes() to consolidate PTE mapping logic
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
` (4 preceding siblings ...)
2026-09-23 6:28 ` [PATCH v9 05/10] arm64/vmalloc: allow arch_vmap_pte_range_map_size() to batch multiple CONT_PTE Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 6:28 ` [PATCH v9 07/10] mm/vmalloc: extend page table walk to support larger page_shift sizes and eliminate page table rewalk Wen Jiang
` (3 subsequent siblings)
9 siblings, 0 replies; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
Extract the common PTE mapping logic from vmap_pte_range() into a
shared helper vmap_set_ptes(). This handles both CONT_PTE and regular
PTE mappings in a single function, preparing for the next patch which
will extend vmap_pages_pte_range() to also use this helper.
No functional change.
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
Tested-by: Leo Yan <leo.yan@arm.com>
---
mm/vmalloc.c | 36 +++++++++++++++++++++++++++---------
1 file changed, 27 insertions(+), 9 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index fb757d95bde25..d475e52110e4a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -92,6 +92,29 @@ struct vfree_deferred {
static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
/*** Page table manipulation functions ***/
+
+/*
+ * Try contiguous mappings at the PTE level for arches which support them, and if
+ * requested by the caller. Fall back to PAGE_SIZE mappings otherwise.
+ *
+ * Return: mapping size.
+ */
+static __always_inline unsigned long vmap_set_ptes(pte_t *ptep,
+ unsigned long addr, unsigned long end, u64 pfn,
+ pgprot_t prot, unsigned int max_page_shift)
+{
+ unsigned long size;
+
+ size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
+ if (size != PAGE_SIZE) {
+ pte_set_huge(ptep, addr, PFN_PHYS(pfn), prot, size);
+ return size;
+ }
+
+ set_pte_at(&init_mm, addr, ptep, pfn_pte(pfn, prot));
+ return PAGE_SIZE;
+}
+
static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift, pgtbl_mod_mask *mask)
@@ -100,6 +123,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
u64 pfn;
struct page *page;
unsigned long size;
+ unsigned int steps;
if (WARN_ON_ONCE(!PAGE_ALIGNED(end - addr)))
return -EINVAL;
@@ -120,15 +144,9 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
BUG();
}
- size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
- if (size != PAGE_SIZE) {
- pte_set_huge(pte, addr, PFN_PHYS(pfn), prot, size);
- pfn += PFN_DOWN(size);
- continue;
- }
- set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
- pfn++;
- } while (pte += PFN_DOWN(size), addr += size, addr != end);
+ size = vmap_set_ptes(pte, addr, end, pfn, prot, max_page_shift);
+ steps = PFN_DOWN(size);
+ } while (pte += steps, pfn += steps, addr += size, addr != end);
lazy_mmu_mode_disable();
*mask |= PGTBL_PTE_MODIFIED;
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* [PATCH v9 07/10] mm/vmalloc: extend page table walk to support larger page_shift sizes and eliminate page table rewalk
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
` (5 preceding siblings ...)
2026-09-23 6:28 ` [PATCH v9 06/10] mm/vmalloc: extract vmap_set_ptes() to consolidate PTE mapping logic Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 6:28 ` [PATCH v9 08/10] mm/vmalloc: extract vm_shift() to consolidate mapping shift selection Wen Jiang
` (2 subsequent siblings)
9 siblings, 0 replies; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
From: "Barry Song (Xiaomi)" <baohua@kernel.org>
vmap_pages_range_noflush_walk() (formerly vmap_small_pages_range_noflush())
provides a clean interface by taking struct page **pages and mapping them
via direct PTE iteration. This avoids the page table rewalk seen when
using vmap_range_noflush() for page_shift values other than PAGE_SHIFT.
Extend it to support larger page_shift values, and add PMD- and
contiguous-PTE mappings as well.
Rename it to vmap_pages_range_noflush_walk() since it now handles
more than just small pages.
For vmalloc() allocations with VM_ALLOW_HUGE_VMAP, we no longer need to
iterate over pages one by one via vmap_range_noflush(), which would
otherwise lead to page table rewalk. The code is now unified with the
PAGE_SHIFT case by simply calling vmap_pages_range_noflush_walk().
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
---
mm/vmalloc.c | 84 +++++++++++++++++++++++++++++++---------------------
1 file changed, 50 insertions(+), 34 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d475e52110e4a..6e0dec73107a7 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -558,8 +558,10 @@ void vunmap_range(unsigned long addr, unsigned long end)
static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr,
- pgtbl_mod_mask *mask)
+ pgtbl_mod_mask *mask, unsigned int shift)
{
+ unsigned long pfn, size;
+ unsigned int steps;
int err = 0;
pte_t *pte;
@@ -590,9 +592,10 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
break;
}
- set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
- (*nr)++;
- } while (pte++, addr += PAGE_SIZE, addr != end);
+ pfn = page_to_pfn(page);
+ size = vmap_set_ptes(pte, addr, end, pfn, prot, shift);
+ steps = PFN_DOWN(size);
+ } while (pte += steps, *nr += steps, addr += size, addr != end);
lazy_mmu_mode_disable();
*mask |= PGTBL_PTE_MODIFIED;
@@ -602,60 +605,88 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr,
- pgtbl_mod_mask *mask)
+ pgtbl_mod_mask *mask, unsigned int shift)
{
pmd_t *pmd;
unsigned long next;
+ int err;
pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
if (!pmd)
return -ENOMEM;
do {
next = pmd_addr_end(addr, end);
- if (vmap_pages_pte_range(pmd, addr, next, prot, pages, nr, mask))
- return -ENOMEM;
+
+ if (shift >= PMD_SHIFT) {
+ struct page *page = pages[*nr];
+ phys_addr_t phys_addr;
+
+ if (WARN_ON(!page))
+ return -ENOMEM;
+ if (WARN_ON(!pfn_valid(page_to_pfn(page))))
+ return -EINVAL;
+
+ phys_addr = page_to_phys(page);
+
+ if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot, shift)) {
+ *mask |= PGTBL_PMD_MODIFIED;
+ *nr += 1 << (PMD_SHIFT - PAGE_SHIFT);
+ continue;
+ }
+ }
+ err = vmap_pages_pte_range(pmd, addr, next, prot, pages, nr, mask, shift);
+ if (err)
+ return err;
} while (pmd++, addr = next, addr != end);
return 0;
}
static int vmap_pages_pud_range(p4d_t *p4d, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr,
- pgtbl_mod_mask *mask)
+ pgtbl_mod_mask *mask, unsigned int shift)
{
pud_t *pud;
unsigned long next;
+ int err;
pud = pud_alloc_track(&init_mm, p4d, addr, mask);
if (!pud)
return -ENOMEM;
do {
next = pud_addr_end(addr, end);
- if (vmap_pages_pmd_range(pud, addr, next, prot, pages, nr, mask))
- return -ENOMEM;
+ err = vmap_pages_pmd_range(pud, addr, next, prot, pages, nr, mask, shift);
+ if (err)
+ return err;
} while (pud++, addr = next, addr != end);
return 0;
}
static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr,
unsigned long end, pgprot_t prot, struct page **pages, int *nr,
- pgtbl_mod_mask *mask)
+ pgtbl_mod_mask *mask, unsigned int shift)
{
p4d_t *p4d;
unsigned long next;
+ int err;
p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
if (!p4d)
return -ENOMEM;
do {
next = p4d_addr_end(addr, end);
- if (vmap_pages_pud_range(p4d, addr, next, prot, pages, nr, mask))
- return -ENOMEM;
+ err = vmap_pages_pud_range(p4d, addr, next, prot, pages, nr, mask, shift);
+ if (err)
+ return err;
} while (p4d++, addr = next, addr != end);
return 0;
}
-static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end,
- pgprot_t prot, struct page **pages)
+/*
+ * It can take an array of pages which are not all contiguous, but it
+ * may have contiguous chunks, as hinted by @shift.
+ */
+static int vmap_pages_range_noflush_walk(unsigned long addr, unsigned long end,
+ pgprot_t prot, struct page **pages, unsigned int shift)
{
unsigned long start = addr;
pgd_t *pgd;
@@ -670,7 +701,7 @@ static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end,
next = pgd_addr_end(addr, end);
if (pgd_bad(*pgd))
mask |= PGTBL_PGD_MODIFIED;
- err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask);
+ err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask, shift);
if (err)
break;
} while (pgd++, addr = next, addr != end);
@@ -693,27 +724,12 @@ static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end,
int __vmap_pages_range_noflush(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift)
{
- unsigned int i, nr = (end - addr) >> PAGE_SHIFT;
-
WARN_ON(page_shift < PAGE_SHIFT);
- if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC) ||
- page_shift == PAGE_SHIFT)
- return vmap_small_pages_range_noflush(addr, end, prot, pages);
+ if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC))
+ page_shift = PAGE_SHIFT;
- for (i = 0; i < nr; i += 1U << (page_shift - PAGE_SHIFT)) {
- int err;
-
- err = vmap_range_noflush(addr, addr + (1UL << page_shift),
- page_to_phys(pages[i]), prot,
- page_shift);
- if (err)
- return err;
-
- addr += 1UL << page_shift;
- }
-
- return 0;
+ return vmap_pages_range_noflush_walk(addr, end, prot, pages, page_shift);
}
int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* [PATCH v9 08/10] mm/vmalloc: extract vm_shift() to consolidate mapping shift selection
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
` (6 preceding siblings ...)
2026-09-23 6:28 ` [PATCH v9 07/10] mm/vmalloc: extend page table walk to support larger page_shift sizes and eliminate page table rewalk Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 6:28 ` [PATCH v9 09/10] mm/vmalloc: map contiguous pages in batches for vmap() if possible Wen Jiang
2026-09-23 6:28 ` [PATCH v9 10/10] mm/vmalloc: align vm_area so vmap() can batch mappings Wen Jiang
9 siblings, 0 replies; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
Extract the vmalloc mapping shift selection from
__vmalloc_node_range_noprof() into vm_shift(), preparing for reuse by the
vmap batching path.
No functional change.
Suggested-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
Tested-by: Leo Yan <leo.yan@arm.com>
---
mm/vmalloc.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 6e0dec73107a7..a43965016eb4d 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3568,6 +3568,14 @@ void vunmap(const void *addr)
}
EXPORT_SYMBOL(vunmap);
+static inline unsigned int vm_shift(pgprot_t prot, unsigned long size)
+{
+ if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE)
+ return PMD_SHIFT;
+
+ return arch_vmap_pte_supported_shift(size);
+}
+
/**
* vmap - map an array of pages into virtually contiguous space
* @pages: array of page pointers
@@ -4079,11 +4087,7 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align,
* supporting them.
*/
- if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE)
- shift = PMD_SHIFT;
- else
- shift = arch_vmap_pte_supported_shift(size);
-
+ shift = vm_shift(prot, size);
align = max(original_align, 1UL << shift);
}
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* [PATCH v9 09/10] mm/vmalloc: map contiguous pages in batches for vmap() if possible
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
` (7 preceding siblings ...)
2026-09-23 6:28 ` [PATCH v9 08/10] mm/vmalloc: extract vm_shift() to consolidate mapping shift selection Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
2026-09-23 6:28 ` [PATCH v9 10/10] mm/vmalloc: align vm_area so vmap() can batch mappings Wen Jiang
9 siblings, 0 replies; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
From: "Barry Song (Xiaomi)" <baohua@kernel.org>
In many cases, the pages passed to vmap() may include high-order
pages. For example, the systemheap often allocates pages in descending
order: order 8, then 4, then 0. Currently, vmap() iterates over every
page individually—even pages inside a high-order block are handled
one by one.
This patch detects physically contiguous pages (regardless of whether
they are compound or non-compound) by scanning with
num_pages_contiguous(), and maps them as a single contiguous block
whenever possible. The mapping order is determined by taking the
minimum of the contiguous page count and the pfn alignment, allowing
graceful degradation when pfn alignment is less than the contiguous
range.
Pages with the same page_shift are coalesced and mapped via
vmap_pages_range_noflush_walk() to avoid page table rewalk.
As users typically allocate memory in descending orders (e.g.
8 → 4 → 0), once an order-0 page is encountered, we stop scanning
for contiguous pages since subsequent pages are likely order-0 as well.
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
Co-developed-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
Tested-by: Leo Yan <leo.yan@arm.com>
---
mm/vmalloc.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 80 insertions(+), 2 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a43965016eb4d..37cddb7f45a4f 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3576,6 +3576,85 @@ static inline unsigned int vm_shift(pgprot_t prot, unsigned long size)
return arch_vmap_pte_supported_shift(size);
}
+static inline int get_vmap_batch_order(struct page **pages,
+ pgprot_t prot, unsigned int nr_pages)
+{
+ unsigned long pfn;
+ unsigned int nr_contig;
+ int order;
+
+ if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP))
+ return 0;
+
+ /* Limit nr_pages by pfn alignment */
+ pfn = page_to_pfn(*pages);
+ if (pfn > 0)
+ nr_pages = min_t(size_t, nr_pages, 1UL << __ffs(pfn));
+
+ nr_contig = num_pages_contiguous(pages, nr_pages);
+ if (nr_contig < 2)
+ return 0;
+
+ order = ilog2(nr_contig);
+
+ if (vm_shift(prot, PAGE_SIZE << order) == PAGE_SHIFT)
+ return 0;
+
+ return order;
+}
+
+static int vmap_pages_range_batched(unsigned long addr, unsigned long end,
+ pgprot_t prot, struct page **pages)
+{
+ const unsigned int nr_pages = (end - addr) >> PAGE_SHIFT;
+ unsigned int prev_shift = 0, batch_idx = 0;
+ unsigned long batch_start = addr, batch_end = addr;
+ int err;
+
+ err = kmsan_vmap_pages_range_noflush(addr, end, prot, pages,
+ PAGE_SHIFT, GFP_KERNEL);
+
+ if (err)
+ goto out;
+
+ for (unsigned int i = 0; i < nr_pages; ) {
+ unsigned int shift = PAGE_SHIFT +
+ get_vmap_batch_order(pages + i, prot, nr_pages - i);
+
+ if (!i)
+ prev_shift = shift;
+
+ if (shift != prev_shift) {
+ err = vmap_pages_range_noflush_walk(batch_start, batch_end,
+ prot, pages + batch_idx, prev_shift);
+ if (err)
+ goto out;
+ prev_shift = shift;
+ batch_start = batch_end;
+ batch_idx = i;
+ }
+
+ /*
+ * Once we fail to batch pages, we expect to fail batching
+ * for all remaining pages, so just give up.
+ */
+ if (shift == PAGE_SHIFT)
+ break;
+
+ batch_end += 1UL << shift;
+ i += 1U << (shift - PAGE_SHIFT);
+ }
+
+ /* Remaining */
+ if (batch_start < end)
+ err = vmap_pages_range_noflush_walk(batch_start, end, prot,
+ pages + batch_idx, prev_shift);
+
+out:
+ flush_cache_vmap(addr, end);
+ return err;
+}
+
/**
* vmap - map an array of pages into virtually contiguous space
* @pages: array of page pointers
@@ -3619,8 +3698,7 @@ void *vmap(struct page **pages, unsigned int count,
return NULL;
addr = (unsigned long)area->addr;
- if (vmap_pages_range(addr, addr + size, pgprot_nx(prot),
- pages, PAGE_SHIFT) < 0) {
+ if (vmap_pages_range_batched(addr, addr + size, pgprot_nx(prot), pages) < 0) {
vunmap(area->addr);
return NULL;
}
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread* [PATCH v9 10/10] mm/vmalloc: align vm_area so vmap() can batch mappings
2026-09-23 6:28 [PATCH v9 00/10] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
` (8 preceding siblings ...)
2026-09-23 6:28 ` [PATCH v9 09/10] mm/vmalloc: map contiguous pages in batches for vmap() if possible Wen Jiang
@ 2026-09-23 6:28 ` Wen Jiang
9 siblings, 0 replies; 15+ messages in thread
From: Wen Jiang @ 2026-09-23 6:28 UTC (permalink / raw)
To: akpm, catalin.marinas, linux-mm, urezki, will
Cc: Xueyuan.chen21, ajd, anshuman.khandual, baohua, chleroy, david,
dev.jain, jiangwen6, leo.yan, linux-arm-kernel, linux-kernel,
linuxppc-dev, maddy, mpe, npiggin, rppt, ryan.roberts
From: "Barry Song (Xiaomi)" <baohua@kernel.org>
Try to align the vmap virtual address to PMD_SHIFT or a
larger PTE mapping size hinted by the architecture, so
contiguous pages can be batch-mapped when setting PMD or
PTE entries. We do not expect any significant overhead for
this.
Add __get_vm_area_node_aligned_caller() as a wrapper over
__get_vm_area_node() to simplify repeated calls with fixed
arguments.
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
---
mm/vmalloc.c | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 37cddb7f45a4f..1a3b191885024 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3328,6 +3328,14 @@ struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
NUMA_NO_NODE, GFP_KERNEL, caller);
}
+static struct vm_struct *__get_vm_area_node_aligned_caller(unsigned long size,
+ unsigned long align, unsigned long flags, const void *caller)
+{
+ return __get_vm_area_node(size, align, PAGE_SHIFT, flags,
+ VMALLOC_START, VMALLOC_END,
+ NUMA_NO_NODE, GFP_KERNEL, caller);
+}
+
/**
* find_vm_area - find a continuous kernel virtual area
* @addr: base address
@@ -3655,6 +3663,30 @@ static int vmap_pages_range_batched(unsigned long addr, unsigned long end,
return err;
}
+static struct vm_struct *vmap_get_aligned_vm_area(unsigned long size,
+ unsigned long flags, pgprot_t prot, const void *caller)
+{
+ struct vm_struct *vm_area;
+ unsigned int shift;
+
+ if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE) {
+ vm_area = __get_vm_area_node_aligned_caller(size, PMD_SIZE,
+ flags, caller);
+ if (vm_area)
+ return vm_area;
+ }
+
+ shift = arch_vmap_pte_supported_shift(size);
+ if (shift > PAGE_SHIFT) {
+ vm_area = __get_vm_area_node_aligned_caller(size, 1UL << shift,
+ flags, caller);
+ if (vm_area)
+ return vm_area;
+ }
+
+ return __get_vm_area_node_aligned_caller(size, PAGE_SIZE, flags, caller);
+}
+
/**
* vmap - map an array of pages into virtually contiguous space
* @pages: array of page pointers
@@ -3693,7 +3725,8 @@ void *vmap(struct page **pages, unsigned int count,
return NULL;
size = (unsigned long)count << PAGE_SHIFT;
- area = get_vm_area_caller(size, flags, __builtin_return_address(0));
+ area = vmap_get_aligned_vm_area(size, flags, prot,
+ __builtin_return_address(0));
if (!area)
return NULL;
--
2.34.1
^ permalink raw reply [flat|nested] 15+ messages in thread