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

Rich Felker
2020-07-20T21:25:24Z

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