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Date:   Wed, 16 Jan 2019 07:57:03 +0100
From:   Michal Hocko <mhocko@kernel.org>
To:     Anshuman Khandual <anshuman.khandual@arm.com>
Cc:     linux-mm@kvack.org, akpm@linux-foundation.org,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-arm-kernel@lists.infradead.org, linux-sh@vger.kernel.org,
        kvmarm@lists.cs.columbia.edu, linux-riscv@lists.infradead.org,
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        will.deacon@arm.com, mpe@ellerman.id.au, tglx@linutronix.de,
        mingo@redhat.com, dave.hansen@linux.intel.com,
        peterz@infradead.org, christoffer.dall@arm.com,
        marc.zyngier@arm.com, kirill@shutemov.name,
        rppt@linux.vnet.ibm.com, ard.biesheuvel@linaro.org,
        mark.rutland@arm.com, steve.capper@arm.com, james.morse@arm.com,
        robin.murphy@arm.com, aneesh.kumar@linux.ibm.com, vbabka@suse.cz,
        shakeelb@google.com, rientjes@google.com, palmer@sifive.com,
        greentime@andestech.com
Subject: Re: [PATCH V2] mm: Introduce GFP_PGTABLE
Message-ID: <20190116065703.GE24149@dhcp22.suse.cz>
References: <1547619692-7946-1-git-send-email-anshuman.khandual@arm.com>
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On Wed 16-01-19 11:51:32, Anshuman Khandual wrote:
> All architectures have been defining their own PGALLOC_GFP as (GFP_KERNEL |
> __GFP_ZERO) and using it for allocating page table pages. This causes some
> code duplication which can be easily avoided. GFP_KERNEL allocated and
> cleared out pages (__GFP_ZERO) are required for page tables on any given
> architecture. This creates a new generic GFP flag flag which can be used
> for any page table page allocation. Does not cause any functional change.
> 
> GFP_PGTABLE is being added into include/asm-generic/pgtable.h which is the
> generic page tabe header just to prevent it's potential misuse as a general
> allocation flag if included in include/linux/gfp.h.

I haven't reviewed the patch yet but I am wondering whether this is
really worth it without going all the way down to unify the common code
and remove much more code duplication. Or is this not possible for some
reason?

> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> Build tested on arm, arm64, powerpc, powerpc64le and x86.
> Boot tested on arm64 and x86.
> 
> Changes in V2:
> 
> - Moved GFP_PGTABLE into include/asm-generic/pgtable.h
> - On X86 added __GFP_ACCOUNT into GFP_PGTABLE at various places
> - Replaced possible flags on riscv and nds32 with GFP_PGTABLE
> 
> Original V1: https://lkml.org/lkml/2019/1/12/54 
> 
>  arch/arm/include/asm/pgalloc.h               |  8 +++-----
>  arch/arm/mm/mmu.c                            |  2 +-
>  arch/arm64/include/asm/pgalloc.h             |  9 ++++-----
>  arch/arm64/mm/mmu.c                          |  2 +-
>  arch/arm64/mm/pgd.c                          |  4 ++--
>  arch/nds32/include/asm/pgalloc.h             |  3 +--
>  arch/powerpc/include/asm/book3s/64/pgalloc.h |  6 +++---
>  arch/powerpc/include/asm/pgalloc.h           |  2 --
>  arch/powerpc/kvm/book3s_64_mmu_hv.c          |  2 +-
>  arch/powerpc/mm/pgtable-frag.c               |  4 ++--
>  arch/riscv/include/asm/pgalloc.h             |  8 +++-----
>  arch/sh/mm/pgtable.c                         |  6 ++----
>  arch/unicore32/include/asm/pgalloc.h         |  6 ++----
>  arch/x86/kernel/espfix_64.c                  |  6 ++----
>  arch/x86/mm/pgtable.c                        | 15 +++++++--------
>  include/asm-generic/pgtable.h                |  2 ++
>  virt/kvm/arm/mmu.c                           |  2 +-
>  17 files changed, 37 insertions(+), 50 deletions(-)
> 
> diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
> index 17ab72f..72be6f5 100644
> --- a/arch/arm/include/asm/pgalloc.h
> +++ b/arch/arm/include/asm/pgalloc.h
> @@ -57,8 +57,6 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
>  extern pgd_t *pgd_alloc(struct mm_struct *mm);
>  extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
>  
> -#define PGALLOC_GFP	(GFP_KERNEL | __GFP_ZERO)
> -
>  static inline void clean_pte_table(pte_t *pte)
>  {
>  	clean_dcache_area(pte + PTE_HWTABLE_PTRS, PTE_HWTABLE_SIZE);
> @@ -85,7 +83,7 @@ pte_alloc_one_kernel(struct mm_struct *mm)
>  {
>  	pte_t *pte;
>  
> -	pte = (pte_t *)__get_free_page(PGALLOC_GFP);
> +	pte = (pte_t *)__get_free_page(GFP_PGTABLE);
>  	if (pte)
>  		clean_pte_table(pte);
>  
> @@ -98,9 +96,9 @@ pte_alloc_one(struct mm_struct *mm)
>  	struct page *pte;
>  
>  #ifdef CONFIG_HIGHPTE
> -	pte = alloc_pages(PGALLOC_GFP | __GFP_HIGHMEM, 0);
> +	pte = alloc_pages(GFP_PGTABLE | __GFP_HIGHMEM, 0);
>  #else
> -	pte = alloc_pages(PGALLOC_GFP, 0);
> +	pte = alloc_pages(GFP_PGTABLE, 0);
>  #endif
>  	if (!pte)
>  		return NULL;
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index f5cc1cc..6d47784 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -733,7 +733,7 @@ static void __init *early_alloc(unsigned long sz)
>  
>  static void *__init late_alloc(unsigned long sz)
>  {
> -	void *ptr = (void *)__get_free_pages(PGALLOC_GFP, get_order(sz));
> +	void *ptr = (void *)__get_free_pages(GFP_PGTABLE, get_order(sz));
>  
>  	if (!ptr || !pgtable_page_ctor(virt_to_page(ptr)))
>  		BUG();
> diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
> index 52fa47c..d5c75bf 100644
> --- a/arch/arm64/include/asm/pgalloc.h
> +++ b/arch/arm64/include/asm/pgalloc.h
> @@ -26,14 +26,13 @@
>  
>  #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);
>  }
>  
>  static inline void pmd_free(struct mm_struct *mm, pmd_t *pmdp)
> @@ -62,7 +61,7 @@ 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);
>  }
>  
>  static inline void pud_free(struct mm_struct *mm, pud_t *pudp)
> @@ -93,7 +92,7 @@ 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);
> +	return (pte_t *)__get_free_page(GFP_PGTABLE);
>  }
>  
>  static inline pgtable_t
> @@ -101,7 +100,7 @@ pte_alloc_one(struct mm_struct *mm)
>  {
>  	struct page *pte;
>  
> -	pte = alloc_pages(PGALLOC_GFP, 0);
> +	pte = alloc_pages(GFP_PGTABLE, 0);
>  	if (!pte)
>  		return NULL;
>  	if (!pgtable_page_ctor(pte)) {
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index b6f5aa5..07b1c0f 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -372,7 +372,7 @@ 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);
>  	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..5b28e2b 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);
>  	else
> -		return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
> +		return kmem_cache_alloc(pgd_cache, GFP_PGTABLE);
>  }
>  
>  void pgd_free(struct mm_struct *mm, pgd_t *pgd)
> diff --git a/arch/nds32/include/asm/pgalloc.h b/arch/nds32/include/asm/pgalloc.h
> index 3c5fee5..e1137ce 100644
> --- a/arch/nds32/include/asm/pgalloc.h
> +++ b/arch/nds32/include/asm/pgalloc.h
> @@ -27,8 +27,7 @@ static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
>  	pte_t *pte;
>  
>  	pte =
> -	    (pte_t *) __get_free_page(GFP_KERNEL | __GFP_RETRY_MAYFAIL |
> -				      __GFP_ZERO);
> +	    (pte_t *) __get_free_page(GFP_PGTABLE | __GFP_RETRY_MAYFAIL);
>  
>  	return pte;
>  }
> diff --git a/arch/powerpc/include/asm/book3s/64/pgalloc.h b/arch/powerpc/include/asm/book3s/64/pgalloc.h
> index 9c11732..71704e5 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgalloc.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h
> @@ -52,11 +52,11 @@ void pte_frag_destroy(void *pte_frag);
>  static inline pgd_t *radix__pgd_alloc(struct mm_struct *mm)
>  {
>  #ifdef CONFIG_PPC_64K_PAGES
> -	return (pgd_t *)__get_free_page(pgtable_gfp_flags(mm, PGALLOC_GFP));
> +	return (pgd_t *)__get_free_page(pgtable_gfp_flags(mm, GFP_PGTABLE));
>  #else
>  	struct page *page;
> -	page = alloc_pages(pgtable_gfp_flags(mm, PGALLOC_GFP | __GFP_RETRY_MAYFAIL),
> -				4);
> +	page = alloc_pages(pgtable_gfp_flags(mm, GFP_PGTABLE |
> +				__GFP_RETRY_MAYFAIL), 4);
>  	if (!page)
>  		return NULL;
>  	return (pgd_t *) page_address(page);
> diff --git a/arch/powerpc/include/asm/pgalloc.h b/arch/powerpc/include/asm/pgalloc.h
> index e11f030..3b11e8b 100644
> --- a/arch/powerpc/include/asm/pgalloc.h
> +++ b/arch/powerpc/include/asm/pgalloc.h
> @@ -18,8 +18,6 @@ static inline gfp_t pgtable_gfp_flags(struct mm_struct *mm, gfp_t gfp)
>  }
>  #endif /* MODULE */
>  
> -#define PGALLOC_GFP (GFP_KERNEL | __GFP_ZERO)
> -
>  #ifdef CONFIG_PPC_BOOK3S
>  #include <asm/book3s/pgalloc.h>
>  #else
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> index bd2dcfb..b419878 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> @@ -97,7 +97,7 @@ int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order)
>  	}
>  
>  	if (!hpt)
> -		hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_RETRY_MAYFAIL
> +		hpt = __get_free_pages(GFP_PGTABLE | __GFP_RETRY_MAYFAIL
>  				       |__GFP_NOWARN, order - PAGE_SHIFT);
>  
>  	if (!hpt)
> diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
> index a7b0521..211aaa7 100644
> --- a/arch/powerpc/mm/pgtable-frag.c
> +++ b/arch/powerpc/mm/pgtable-frag.c
> @@ -58,7 +58,7 @@ static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int kernel)
>  	struct page *page;
>  
>  	if (!kernel) {
> -		page = alloc_page(PGALLOC_GFP | __GFP_ACCOUNT);
> +		page = alloc_page(GFP_PGTABLE | __GFP_ACCOUNT);
>  		if (!page)
>  			return NULL;
>  		if (!pgtable_page_ctor(page)) {
> @@ -66,7 +66,7 @@ static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int kernel)
>  			return NULL;
>  		}
>  	} else {
> -		page = alloc_page(PGALLOC_GFP);
> +		page = alloc_page(GFP_PGTABLE);
>  		if (!page)
>  			return NULL;
>  	}
> diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
> index 94043cf..7ff1cd7 100644
> --- a/arch/riscv/include/asm/pgalloc.h
> +++ b/arch/riscv/include/asm/pgalloc.h
> @@ -69,8 +69,7 @@ static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
>  
>  static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
>  {
> -	return (pmd_t *)__get_free_page(
> -		GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
> +	return (pmd_t *)__get_free_page(GFP_PGTABLE | __GFP_RETRY_MAYFAIL);
>  }
>  
>  static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
> @@ -84,15 +83,14 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
>  
>  static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
>  {
> -	return (pte_t *)__get_free_page(
> -		GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
> +	return (pte_t *)__get_free_page(GFP_PGTABLE | __GFP_RETRY_MAYFAIL);
>  }
>  
>  static inline struct page *pte_alloc_one(struct mm_struct *mm)
>  {
>  	struct page *pte;
>  
> -	pte = alloc_page(GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
> +	pte = alloc_page(GFP_PGTABLE | __GFP_RETRY_MAYFAIL);
>  	if (likely(pte != NULL))
>  		pgtable_page_ctor(pte);
>  	return pte;
> diff --git a/arch/sh/mm/pgtable.c b/arch/sh/mm/pgtable.c
> index 5c8f924..324732dc5 100644
> --- a/arch/sh/mm/pgtable.c
> +++ b/arch/sh/mm/pgtable.c
> @@ -2,8 +2,6 @@
>  #include <linux/mm.h>
>  #include <linux/slab.h>
>  
> -#define PGALLOC_GFP GFP_KERNEL | __GFP_ZERO
> -
>  static struct kmem_cache *pgd_cachep;
>  #if PAGETABLE_LEVELS > 2
>  static struct kmem_cache *pmd_cachep;
> @@ -32,7 +30,7 @@ void pgtable_cache_init(void)
>  
>  pgd_t *pgd_alloc(struct mm_struct *mm)
>  {
> -	return kmem_cache_alloc(pgd_cachep, PGALLOC_GFP);
> +	return kmem_cache_alloc(pgd_cachep, GFP_PGTABLE);
>  }
>  
>  void pgd_free(struct mm_struct *mm, pgd_t *pgd)
> @@ -48,7 +46,7 @@ void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
>  
>  pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
>  {
> -	return kmem_cache_alloc(pmd_cachep, PGALLOC_GFP);
> +	return kmem_cache_alloc(pmd_cachep, GFP_PGTABLE);
>  }
>  
>  void pmd_free(struct mm_struct *mm, pmd_t *pmd)
> diff --git a/arch/unicore32/include/asm/pgalloc.h b/arch/unicore32/include/asm/pgalloc.h
> index 7cceabe..a3506e5 100644
> --- a/arch/unicore32/include/asm/pgalloc.h
> +++ b/arch/unicore32/include/asm/pgalloc.h
> @@ -28,8 +28,6 @@ extern void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd);
>  #define pgd_alloc(mm)			get_pgd_slow(mm)
>  #define pgd_free(mm, pgd)		free_pgd_slow(mm, pgd)
>  
> -#define PGALLOC_GFP	(GFP_KERNEL | __GFP_ZERO)
> -
>  /*
>   * Allocate one PTE table.
>   */
> @@ -38,7 +36,7 @@ pte_alloc_one_kernel(struct mm_struct *mm)
>  {
>  	pte_t *pte;
>  
> -	pte = (pte_t *)__get_free_page(PGALLOC_GFP);
> +	pte = (pte_t *)__get_free_page(GFP_PGTABLE);
>  	if (pte)
>  		clean_dcache_area(pte, PTRS_PER_PTE * sizeof(pte_t));
>  
> @@ -50,7 +48,7 @@ pte_alloc_one(struct mm_struct *mm)
>  {
>  	struct page *pte;
>  
> -	pte = alloc_pages(PGALLOC_GFP, 0);
> +	pte = alloc_pages(GFP_PGTABLE, 0);
>  	if (!pte)
>  		return NULL;
>  	if (!PageHighMem(pte)) {
> diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c
> index aebd0d5..dae28cc 100644
> --- a/arch/x86/kernel/espfix_64.c
> +++ b/arch/x86/kernel/espfix_64.c
> @@ -57,8 +57,6 @@
>  # error "Need more virtual address space for the ESPFIX hack"
>  #endif
>  
> -#define PGALLOC_GFP (GFP_KERNEL | __GFP_ZERO)
> -
>  /* This contains the *bottom* address of the espfix stack */
>  DEFINE_PER_CPU_READ_MOSTLY(unsigned long, espfix_stack);
>  DEFINE_PER_CPU_READ_MOSTLY(unsigned long, espfix_waddr);
> @@ -172,7 +170,7 @@ void init_espfix_ap(int cpu)
>  	pud_p = &espfix_pud_page[pud_index(addr)];
>  	pud = *pud_p;
>  	if (!pud_present(pud)) {
> -		struct page *page = alloc_pages_node(node, PGALLOC_GFP, 0);
> +		struct page *page = alloc_pages_node(node, GFP_PGTABLE, 0);
>  
>  		pmd_p = (pmd_t *)page_address(page);
>  		pud = __pud(__pa(pmd_p) | (PGTABLE_PROT & ptemask));
> @@ -184,7 +182,7 @@ void init_espfix_ap(int cpu)
>  	pmd_p = pmd_offset(&pud, addr);
>  	pmd = *pmd_p;
>  	if (!pmd_present(pmd)) {
> -		struct page *page = alloc_pages_node(node, PGALLOC_GFP, 0);
> +		struct page *page = alloc_pages_node(node, GFP_PGTABLE, 0);
>  
>  		pte_p = (pte_t *)page_address(page);
>  		pmd = __pmd(__pa(pte_p) | (PGTABLE_PROT & ptemask));
> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
> index 7bd0170..a5b1672 100644
> --- a/arch/x86/mm/pgtable.c
> +++ b/arch/x86/mm/pgtable.c
> @@ -13,19 +13,17 @@ phys_addr_t physical_mask __ro_after_init = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
>  EXPORT_SYMBOL(physical_mask);
>  #endif
>  
> -#define PGALLOC_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
> -
>  #ifdef CONFIG_HIGHPTE
>  #define PGALLOC_USER_GFP __GFP_HIGHMEM
>  #else
>  #define PGALLOC_USER_GFP 0
>  #endif
>  
> -gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP;
> +gfp_t __userpte_alloc_gfp = GFP_PGTABLE | __GFP_ACCOUNT | PGALLOC_USER_GFP;
>  
>  pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
>  {
> -	return (pte_t *)__get_free_page(PGALLOC_GFP & ~__GFP_ACCOUNT);
> +	return (pte_t *)__get_free_page(GFP_PGTABLE);
>  }
>  
>  pgtable_t pte_alloc_one(struct mm_struct *mm)
> @@ -235,7 +233,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
>  {
>  	int i;
>  	bool failed = false;
> -	gfp_t gfp = PGALLOC_GFP;
> +	gfp_t gfp = GFP_PGTABLE | __GFP_ACCOUNT;
>  
>  	if (mm == &init_mm)
>  		gfp &= ~__GFP_ACCOUNT;
> @@ -401,14 +399,14 @@ static inline pgd_t *_pgd_alloc(void)
>  	 * We allocate one page for pgd.
>  	 */
>  	if (!SHARED_KERNEL_PMD)
> -		return (pgd_t *)__get_free_pages(PGALLOC_GFP,
> +		return (pgd_t *)__get_free_pages(GFP_PGTABLE | __GFP_ACCOUNT,
>  						 PGD_ALLOCATION_ORDER);
>  
>  	/*
>  	 * Now PAE kernel is not running as a Xen domain. We can allocate
>  	 * a 32-byte slab for pgd to save memory space.
>  	 */
> -	return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
> +	return kmem_cache_alloc(pgd_cache, GFP_PGTABLE | __GFP_ACCOUNT);
>  }
>  
>  static inline void _pgd_free(pgd_t *pgd)
> @@ -422,7 +420,8 @@ static inline void _pgd_free(pgd_t *pgd)
>  
>  static inline pgd_t *_pgd_alloc(void)
>  {
> -	return (pgd_t *)__get_free_pages(PGALLOC_GFP, PGD_ALLOCATION_ORDER);
> +	return (pgd_t *)__get_free_pages(GFP_PGTABLE | __GFP_ACCOUNT,
> +						PGD_ALLOCATION_ORDER);
>  }
>  
>  static inline void _pgd_free(pgd_t *pgd)
> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
> index 05e61e6..3d9cde6 100644
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -1186,4 +1186,6 @@ static inline bool arch_has_pfn_modify_check(void)
>  #define mm_pmd_folded(mm)	__is_defined(__PAGETABLE_PMD_FOLDED)
>  #endif
>  
> +#define GFP_PGTABLE	(GFP_KERNEL | __GFP_ZERO)
> +
>  #endif /* _ASM_GENERIC_PGTABLE_H */
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index fbdf3ac..f60a5b8 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -143,7 +143,7 @@ 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);
>  		if (!page)
>  			return -ENOMEM;
>  		cache->objects[cache->nobjs++] = page;
> -- 
> 2.7.4
> 

-- 
Michal Hocko
SUSE Labs