Re: [PATCH 04/15] arm64: switch to generic version of pte allocation
On Fri, May 03, 2019 at 11:05:09AM +0100, Mark Rutland wrote:
> Hi,
>
> On Thu, May 02, 2019 at 06:28:31PM +0300, Mike Rapoport wrote:
> > The PTE allocations in arm64 are identical to the generic ones modulo the
> > GFP flags.
> >
> > Using the generic pte_alloc_one() functions ensures that the user page
> > tables are allocated with __GFP_ACCOUNT set.
> >
> > The arm64 definition of PGALLOC_GFP is removed and replaced with
> > GFP_PGTABLE_USER for p[gum]d_alloc_one() and for KVM memory cache.
> >
> > The mappings created with create_pgd_mapping() are now using
> > GFP_PGTABLE_KERNEL.
> >
> > The conversion to the generic version of pte_free_kernel() removes the NULL
> > check for pte.
> >
> > The pte_free() version on arm64 is identical to the generic one and
> > can be simply dropped.
> >
> > Signed-off-by: Mike Rapoport
> > ---
> > arch/arm64/include/asm/pgalloc.h | 43
> >
> > arch/arm64/mm/mmu.c | 2 +-
> > arch/arm64/mm/pgd.c | 4 ++--
> > virt/kvm/arm/mmu.c | 2 +-
> > 4 files changed, 8 insertions(+), 43 deletions(-)
>
> [...]
>
> > diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c
> > index 289f911..2ef1a53 100644
> > --- a/arch/arm64/mm/pgd.c
> > +++ b/arch/arm64/mm/pgd.c
> > @@ -31,9 +31,9 @@ static struct kmem_cache *pgd_cache __ro_after_init;
> > pgd_t *pgd_alloc(struct mm_struct *mm)
> > {
> > if (PGD_SIZE == PAGE_SIZE)
> > - return (pgd_t *)__get_free_page(PGALLOC_GFP);
> > + return (pgd_t *)__get_free_page(GFP_PGTABLE_USER);
> > else
> > - return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
> > + return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_USER);
> > }
>
> In efi_virtmap_init() we use pgd_alloc() to allocate a pgd for EFI
> runtime services, which we map with a special kernel page table.
>
> I'm not sure if accounting that is problematic, as it's allocated in a
> kernel thread off the back of an early_initcall.
The accounting bypasses kernel threads so there should be no problem.
> Just to check, Is that sound, or do we need a pgd_alloc_kernel()?
>
> Thanks,
> Mark.
>
--
Sincerely yours,
Mike.
Re: [PATCH 04/15] arm64: switch to generic version of pte allocation
Hi,
On Thu, May 02, 2019 at 06:28:31PM +0300, Mike Rapoport wrote:
> The PTE allocations in arm64 are identical to the generic ones modulo the
> GFP flags.
>
> Using the generic pte_alloc_one() functions ensures that the user page
> tables are allocated with __GFP_ACCOUNT set.
>
> The arm64 definition of PGALLOC_GFP is removed and replaced with
> GFP_PGTABLE_USER for p[gum]d_alloc_one() and for KVM memory cache.
>
> The mappings created with create_pgd_mapping() are now using
> GFP_PGTABLE_KERNEL.
>
> The conversion to the generic version of pte_free_kernel() removes the NULL
> check for pte.
>
> The pte_free() version on arm64 is identical to the generic one and
> can be simply dropped.
>
> Signed-off-by: Mike Rapoport
> ---
> arch/arm64/include/asm/pgalloc.h | 43
>
> arch/arm64/mm/mmu.c | 2 +-
> arch/arm64/mm/pgd.c | 4 ++--
> virt/kvm/arm/mmu.c | 2 +-
> 4 files changed, 8 insertions(+), 43 deletions(-)
[...]
> diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c
> index 289f911..2ef1a53 100644
> --- a/arch/arm64/mm/pgd.c
> +++ b/arch/arm64/mm/pgd.c
> @@ -31,9 +31,9 @@ static struct kmem_cache *pgd_cache __ro_after_init;
> pgd_t *pgd_alloc(struct mm_struct *mm)
> {
> if (PGD_SIZE == PAGE_SIZE)
> - return (pgd_t *)__get_free_page(PGALLOC_GFP);
> + return (pgd_t *)__get_free_page(GFP_PGTABLE_USER);
> else
> - return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
> + return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_USER);
> }
In efi_virtmap_init() we use pgd_alloc() to allocate a pgd for EFI
runtime services, which we map with a special kernel page table.
I'm not sure if accounting that is problematic, as it's allocated in a
kernel thread off the back of an early_initcall.
Just to check, Is that sound, or do we need a pgd_alloc_kernel()?
Thanks,
Mark.
[PATCH 04/15] arm64: switch to generic version of pte allocation
The PTE allocations in arm64 are identical to the generic ones modulo the
GFP flags.
Using the generic pte_alloc_one() functions ensures that the user page
tables are allocated with __GFP_ACCOUNT set.
The arm64 definition of PGALLOC_GFP is removed and replaced with
GFP_PGTABLE_USER for p[gum]d_alloc_one() and for KVM memory cache.
The mappings created with create_pgd_mapping() are now using
GFP_PGTABLE_KERNEL.
The conversion to the generic version of pte_free_kernel() removes the NULL
check for pte.
The pte_free() version on arm64 is identical to the generic one and
can be simply dropped.
Signed-off-by: Mike Rapoport
---
arch/arm64/include/asm/pgalloc.h | 43
arch/arm64/mm/mmu.c | 2 +-
arch/arm64/mm/pgd.c | 4 ++--
virt/kvm/arm/mmu.c | 2 +-
4 files changed, 8 insertions(+), 43 deletions(-)
diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 52fa47c..3293b8b 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -24,16 +24,17 @@
#include
#include
+#include/* for pte_{alloc,free}_one */
+
#define check_pgt_cache() do { } while (0)
-#define PGALLOC_GFP(GFP_KERNEL | __GFP_ZERO)
#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
#if CONFIG_PGTABLE_LEVELS > 2
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
{
- return (pmd_t *)__get_free_page(PGALLOC_GFP);
+ return (pmd_t *)__get_free_page(GFP_PGTABLE_USER);
}
static inline void pmd_free(struct mm_struct *mm, pmd_t *pmdp)
@@ -62,7 +63,7 @@ static inline void __pud_populate(pud_t *pudp, phys_addr_t
pmdp, pudval_t prot)
static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
{
- return (pud_t *)__get_free_page(PGALLOC_GFP);
+ return (pud_t *)__get_free_page(GFP_PGTABLE_USER);
}
static inline void pud_free(struct mm_struct *mm, pud_t *pudp)
@@ -90,42 +91,6 @@ static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t
pudp, pgdval_t prot)
extern pgd_t *pgd_alloc(struct mm_struct *mm);
extern void pgd_free(struct mm_struct *mm, pgd_t *pgdp);
-static inline pte_t *
-pte_alloc_one_kernel(struct mm_struct *mm)
-{
- return (pte_t *)__get_free_page(PGALLOC_GFP);
-}
-
-static inline pgtable_t
-pte_alloc_one(struct mm_struct *mm)
-{
- struct page *pte;
-
- pte = alloc_pages(PGALLOC_GFP, 0);
- if (!pte)
- return NULL;
- if (!pgtable_page_ctor(pte)) {
- __free_page(pte);
- return NULL;
- }
- return pte;
-}
-
-/*
- * Free a PTE table.
- */
-static inline void pte_free_kernel(struct mm_struct *mm, pte_t *ptep)
-{
- if (ptep)
- free_page((unsigned long)ptep);
-}
-
-static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
-{
- pgtable_page_dtor(pte);
- __free_page(pte);
-}
-
static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t ptep,
pmdval_t prot)
{
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index e97f018..d5178c5 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -373,7 +373,7 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t
phys,
static phys_addr_t pgd_pgtable_alloc(void)
{
- void *ptr = (void *)__get_free_page(PGALLOC_GFP);
+ void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
if (!ptr || !pgtable_page_ctor(virt_to_page(ptr)))
BUG();
diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c
index 289f911..2ef1a53 100644
--- a/arch/arm64/mm/pgd.c
+++ b/arch/arm64/mm/pgd.c
@@ -31,9 +31,9 @@ static struct kmem_cache *pgd_cache __ro_after_init;
pgd_t *pgd_alloc(struct mm_struct *mm)
{
if (PGD_SIZE == PAGE_SIZE)
- return (pgd_t *)__get_free_page(PGALLOC_GFP);
+ return (pgd_t *)__get_free_page(GFP_PGTABLE_USER);
else
- return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
+ return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_USER);
}
void pgd_free(struct mm_struct *mm, pgd_t *pgd)
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 27c9583..9f6f638 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -141,7 +141,7 @@ static int mmu_topup_memory_cache(struct
kvm_mmu_memory_cache *cache,
if (cache->nobjs >= min)
return 0;
while (cache->nobjs < max) {
- page = (void *)__get_free_page(PGALLOC_GFP);
+ page = (void *)__get_free_page(GFP_PGTABLE_USER);
if (!page)
return -ENOMEM;
cache->objects[cache->nobjs++] = page;
--
2.7.4
