linux-kernel - Re: [PATCH 1/1] csky: add page fault perf event support

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Date:   Fri, 19 Apr 2019 19:18:25 +0800
From:   Guo Ren <guoren@...nel.org>
To:     Mao Han <han_mao@...ky.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] csky: add page fault perf event support

Looks good, nice Job, Maomao

On Thu, Apr 18, 2019 at 02:20:40PM +0800, Mao Han wrote:
> This patch add support for page fault count, major fault count
> and minorfault count. Without this patch page faults are not
> sampled for perf event.
> 
>  Performance counter stats for '/usr/lib/perf-test/callchain_test':
>                  0      page-faults               #    0.000 K/sec
> 
> Signed-off-by: Mao Han <han_mao@...ky.com>
> ---
>  arch/csky/mm/fault.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
> index e1725f8..d07141d 100644
> --- a/arch/csky/mm/fault.c
> +++ b/arch/csky/mm/fault.c
> @@ -17,6 +17,7 @@
>  #include <linux/vt_kern.h>
>  #include <linux/extable.h>
>  #include <linux/uaccess.h>
> +#include <linux/perf_event.h>
>  
>  #include <asm/hardirq.h>
>  #include <asm/mmu_context.h>
> @@ -106,6 +107,8 @@ 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..
> @@ -153,10 +156,15 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
>  			goto bad_area;
>  		BUG();
>  	}
> -	if (fault & VM_FAULT_MAJOR)
> +	if (fault & VM_FAULT_MAJOR) {
>  		tsk->maj_flt++;
> -	else
> +		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);
>  	return;
> -- 
> 2.7.4
>