On Fri, 26 Jun 2020 15:36:25 PDT (-0700), pet...@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.walms...@sifive.com> CC: Palmer Dabbelt <pal...@dabbelt.com> CC: Albert Ou <a...@eecs.berkeley.edu> CC: linux-ri...@lists.infradead.org Signed-off-by: Peter Xu <pet...@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 <palmerdabb...@google.com> Thanks!
