[PATCH 20/25] mm/sh: Use mm_fault_accounting()

[PATCH 20/25] mm/sh: Use mm_fault_accounting()

[Peter Xu]

Use the new mm_fault_accounting() helper for page fault accounting.

Avoid doing page fault accounting multiple times if the page fault is retried.

CC: Yoshinori Sato <ysato@users.sourceforge.jp>
CC: Rich Felker <dalias@libc.org>
CC: linux-sh@vger.kernel.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 arch/sh/mm/fault.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index 5f23d7907597..06b232973488 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -379,7 +379,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	struct task_struct *tsk;
 	struct mm_struct *mm;
 	struct vm_area_struct * vma;
-	vm_fault_t fault;
+	vm_fault_t fault, major = 0;
 	unsigned int flags = FAULT_FLAG_DEFAULT;
 
 	tsk = current;
@@ -412,8 +412,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	if ((regs->sr & SR_IMASK) != SR_IMASK)
 		local_irq_enable();
 
-	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
-
 	/*
 	 * If we're in an interrupt, have no user context or are running
 	 * with pagefaults disabled then we must not take the fault:
@@ -465,21 +463,13 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	 * the fault.
 	 */
 	fault = handle_mm_fault(vma, address, flags);
+	major |= fault & VM_FAULT_MAJOR;
 
 	if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
 		if (mm_fault_error(regs, error_code, address, fault))
 			return;
 
 	if (flags & FAULT_FLAG_ALLOW_RETRY) {
-		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);
-		}
 		if (fault & VM_FAULT_RETRY) {
 			flags |= FAULT_FLAG_TRIED;
 
@@ -493,4 +483,5 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	}
 
 	up_read(&mm->mmap_sem);
+	mm_fault_accounting(tsk, regs, address, major);
 }
-- 
2.26.2

Re: [PATCH 20/25] mm/sh: Use mm_fault_accounting()

[Rich Felker]

On Mon, Jun 15, 2020 at 06:23:06PM -0400, Peter Xu wrote:
> Use the new mm_fault_accounting() helper for page fault accounting.
> 
> Avoid doing page fault accounting multiple times if the page fault is retried.
> 
> CC: Yoshinori Sato <ysato@users.sourceforge.jp>
> CC: Rich Felker <dalias@libc.org>
> CC: linux-sh@vger.kernel.org
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  arch/sh/mm/fault.c | 15 +++------------
>  1 file changed, 3 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
> index 5f23d7907597..06b232973488 100644
> --- a/arch/sh/mm/fault.c
> +++ b/arch/sh/mm/fault.c
> @@ -379,7 +379,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
>  	struct task_struct *tsk;
>  	struct mm_struct *mm;
>  	struct vm_area_struct * vma;
> -	vm_fault_t fault;
> +	vm_fault_t fault, major = 0;
>  	unsigned int flags = FAULT_FLAG_DEFAULT;
>  
>  	tsk = current;
> @@ -412,8 +412,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
>  	if ((regs->sr & SR_IMASK) != SR_IMASK)
>  		local_irq_enable();
>  
> -	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
> -
>  	/*
>  	 * If we're in an interrupt, have no user context or are running
>  	 * with pagefaults disabled then we must not take the fault:
> @@ -465,21 +463,13 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
>  	 * the fault.
>  	 */
>  	fault = handle_mm_fault(vma, address, flags);
> +	major |= fault & VM_FAULT_MAJOR;
>  
>  	if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
>  		if (mm_fault_error(regs, error_code, address, fault))
>  			return;
>  
>  	if (flags & FAULT_FLAG_ALLOW_RETRY) {
> -		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);
> -		}
>  		if (fault & VM_FAULT_RETRY) {
>  			flags |= FAULT_FLAG_TRIED;
>  
> @@ -493,4 +483,5 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
>  	}
>  
>  	up_read(&mm->mmap_sem);
> +	mm_fault_accounting(tsk, regs, address, major);
>  }
> -- 
> 2.26.2

What's the status on the rest of this series? Do you need any action
from my side (arch/sh) at this time?

Rich

Re: [PATCH 20/25] mm/sh: Use mm_fault_accounting()

[Peter Xu]

Hi, Rich,

On Mon, Jul 20, 2020 at 05:25:24PM -0400, Rich Felker wrote:
> What's the status on the rest of this series? Do you need any action
> from my side (arch/sh) at this time?

This series should have been queued by Andrew in -next.  So iiuc no further
action is needed.

Thanks for asking,

-- 
Peter Xu