lkml.org 
[lkml]   [2020]   [Jul]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH 17/26] mm/riscv: Use general page fault accounting
From
On Fri, 26 Jun 2020 15:36:25 PDT (-0700), peterx@redhat.com wrote:
> Use the general page fault accounting by passing regs into handle_mm_fault().
> It naturally solve the issue of multiple page fault accounting when page fault
> retry happened.
>
> CC: Paul Walmsley <paul.walmsley@sifive.com>
> CC: Palmer Dabbelt <palmer@dabbelt.com>
> CC: Albert Ou <aou@eecs.berkeley.edu>
> CC: linux-riscv@lists.infradead.org
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
> arch/riscv/mm/fault.c | 16 +---------------
> 1 file changed, 1 insertion(+), 15 deletions(-)
>
> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> index 677ee1bb11ac..e796ba02b572 100644
> --- a/arch/riscv/mm/fault.c
> +++ b/arch/riscv/mm/fault.c
> @@ -110,7 +110,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
> * make sure we exit gracefully rather than endlessly redo
> * the fault.
> */
> - fault = handle_mm_fault(vma, addr, flags, NULL);
> + fault = handle_mm_fault(vma, addr, flags, regs);
>
> /*
> * If we need to retry but a fatal signal is pending, handle the
> @@ -128,21 +128,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
> BUG();
> }
>
> - /*
> - * Major/minor page fault accounting is only done on the
> - * initial attempt. If we go through a retry, it is extremely
> - * likely that the page will be found in page cache at that point.
> - */
> 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, addr);
> - } else {
> - tsk->min_flt++;
> - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
> - 1, regs, addr);
> - }
> if (fault & VM_FAULT_RETRY) {
> flags |= FAULT_FLAG_TRIED;

This still slightly changes the accounting numbers, but I don't think it does
so in a way that's meaningful enough to care about. SIGBUS is the only one
that might happen frequently enough to notice, I doubt anyone cares about
whether faults are accounted for during OOM.

Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>

Thanks!

\
 
 \ /
  Last update: 2020-07-11 21:44    [W:1.433 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site