linux-kernel - Re: [PATCH 07/25] mm/csky: Use mm_fault

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Message-ID: <CAJF2gTSVSXO=phc1eeb-ZmDMrSDjSSLd3tN6ng_8n-pCSZh5zw@mail.gmail.com>
Date:   Wed, 17 Jun 2020 15:04:49 +0800
From:   Guo Ren <guoren@...nel.org>
To:     Peter Xu <peterx@...hat.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Gerald Schaefer <gerald.schaefer@...ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        linux-csky@...r.kernel.org
Subject: Re: [PATCH 07/25] mm/csky: Use mm_fault_accounting()

Hi Peter,

On Tue, Jun 16, 2020 at 6:16 AM Peter Xu <peterx@...hat.com> wrote:
>
> Use the new mm_fault_accounting() helper for page fault accounting.
> Also, move the accounting to be after release of mmap_sem.
>
> CC: Guo Ren <guoren@...nel.org>
> CC: linux-csky@...r.kernel.org
> Signed-off-by: Peter Xu <peterx@...hat.com>
> ---
>  arch/csky/mm/fault.c | 13 +------------
>  1 file changed, 1 insertion(+), 12 deletions(-)
>
> diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
> index 4e6dc68f3258..8f8d34d27eca 100644
> --- a/arch/csky/mm/fault.c
> +++ b/arch/csky/mm/fault.c
> @@ -111,8 +111,6 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
>                 return;
>         }
>  #endif
> -
> -       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
>         /*
>          * If we're in an interrupt or have no user
>          * context, we must not take the fault..
> @@ -160,17 +158,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
>                         goto bad_area;
>                 BUG();
>         }
> -       if (fault & VM_FAULT_MAJOR) {
> -               tsk->maj_flt++;
> -               perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
> -                             address);
> -       } else {
> -               tsk->min_flt++;
> -               perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
> -                             address);
> -       }
> -
>         up_read(&mm->mmap_sem);
> +       mm_fault_accounting(tsk, regs, address, fault & VM_FAULT_MAJOR);
>         return;
>
>         /*
> --
> 2.26.2
>
I notice that you move it out of mm->mmap_sem's area, all archs should
follow the rule ? Can you give me a clarification and put it into de
commit log ?
Thx
-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/