linux-kernel - Re: [PATCH 14/15] um: switch to generic version of pte allocation

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Message-ID: <3fddc076-1843-ee84-febb-44c8d317489f@cambridgegreys.com>
Date:   Fri, 3 May 2019 14:28:56 +0100
From:   Anton Ivanov <anton.ivanov@...bridgegreys.com>
To:     Mike Rapoport <rppt@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Michal Hocko <mhocko@...e.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Palmer Dabbelt <palmer@...ive.com>, linux-mips@...r.kernel.org,
        Guo Ren <guoren@...nel.org>, linux-hexagon@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-arch@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        Helge Deller <deller@....de>, x86@...nel.org,
        Russell King <linux@...linux.org.uk>,
        Matthew Wilcox <willy@...radead.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Matt Turner <mattst88@...il.com>,
        Sam Creasey <sammy@...my.net>, Arnd Bergmann <arnd@...db.de>,
        linux-um@...ts.infradead.org, Richard Weinberger <richard@....at>,
        linux-m68k@...ts.linux-m68k.org, Greentime Hu <green.hu@...il.com>,
        nios2-dev@...ts.rocketboards.org, Guan Xuetao <gxt@....edu.cn>,
        linux-arm-kernel@...ts.infradead.org, linux-parisc@...r.kernel.org,
        linux-kernel@...r.kernel.org, Richard Kuo <rkuo@...eaurora.org>,
        Paul Burton <paul.burton@...s.com>,
        linux-alpha@...r.kernel.org, Ley Foon Tan <lftan@...era.com>,
        linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH 14/15] um: switch to generic version of pte allocation



On 02/05/2019 16:28, Mike Rapoport wrote:
> um allocates PTE pages with __get_free_page() and uses
> GFP_KERNEL | __GFP_ZERO for the allocations.
> 
> Switch it to the generic version that does exactly the same thing for the
> kernel page tables and adds __GFP_ACCOUNT for the user PTEs.
> 
> The pte_free() and pte_free_kernel() versions are identical to the generic
> ones and can be simply dropped.
> 
> Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
> ---
>   arch/um/include/asm/pgalloc.h | 16 ++--------------
>   arch/um/kernel/mem.c          | 22 ----------------------
>   2 files changed, 2 insertions(+), 36 deletions(-)
> 
> diff --git a/arch/um/include/asm/pgalloc.h b/arch/um/include/asm/pgalloc.h
> index 99eb568..d7b282e 100644
> --- a/arch/um/include/asm/pgalloc.h
> +++ b/arch/um/include/asm/pgalloc.h
> @@ -10,6 +10,8 @@
>   
>   #include <linux/mm.h>
>   
> +#include <asm-generic/pgalloc.h>	/* for pte_{alloc,free}_one */
> +
>   #define pmd_populate_kernel(mm, pmd, pte) \
>   	set_pmd(pmd, __pmd(_PAGE_TABLE + (unsigned long) __pa(pte)))
>   
> @@ -25,20 +27,6 @@
>   extern pgd_t *pgd_alloc(struct mm_struct *);
>   extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
>   
> -extern pte_t *pte_alloc_one_kernel(struct mm_struct *);
> -extern pgtable_t pte_alloc_one(struct mm_struct *);
> -
> -static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
> -{
> -	free_page((unsigned long) pte);
> -}
> -
> -static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
> -{
> -	pgtable_page_dtor(pte);
> -	__free_page(pte);
> -}
> -
>   #define __pte_free_tlb(tlb,pte, address)		\
>   do {							\
>   	pgtable_page_dtor(pte);				\
> diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
> index 99aa11b..2280374 100644
> --- a/arch/um/kernel/mem.c
> +++ b/arch/um/kernel/mem.c
> @@ -215,28 +215,6 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd)
>   	free_page((unsigned long) pgd);
>   }
>   
> -pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
> -{
> -	pte_t *pte;
> -
> -	pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
> -	return pte;
> -}
> -
> -pgtable_t pte_alloc_one(struct mm_struct *mm)
> -{
> -	struct page *pte;
> -
> -	pte = alloc_page(GFP_KERNEL|__GFP_ZERO);
> -	if (!pte)
> -		return NULL;
> -	if (!pgtable_page_ctor(pte)) {
> -		__free_page(pte);
> -		return NULL;
> -	}
> -	return pte;
> -}
> -
>   #ifdef CONFIG_3_LEVEL_PGTABLES
>   pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
>   {
> 


Reviewed-by: Anton Ivanov <anton.ivanov@...bridgegreys.com>
Acked-by: Anton Ivanov <anton.ivanov@...bridgegreys.com>

-- 
Anton R. Ivanov
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