From: Peter Xu <peterx@xxxxxxxxxx> Subject: mm/nios2: use general page fault accounting 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. Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too. Note, the other two perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in handle_mm_fault(). Link: http://lkml.kernel.org/r/20200707225021.200906-14-peterx@xxxxxxxxxx Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> Cc: Ley Foon Tan <ley.foon.tan@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/nios2/mm/fault.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) --- a/arch/nios2/mm/fault.c~mm-nios2-use-general-page-fault-accounting +++ a/arch/nios2/mm/fault.c @@ -24,6 +24,7 @@ #include <linux/mm.h> #include <linux/extable.h> #include <linux/uaccess.h> +#include <linux/perf_event.h> #include <asm/mmu_context.h> #include <asm/traps.h> @@ -83,6 +84,8 @@ asmlinkage void do_page_fault(struct pt_ if (user_mode(regs)) flags |= FAULT_FLAG_USER; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); + if (!mmap_read_trylock(mm)) { if (!user_mode(regs) && !search_exception_tables(regs->ea)) goto bad_area_nosemaphore; @@ -131,7 +134,7 @@ good_area: * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags, NULL); + fault = handle_mm_fault(vma, address, flags, regs); if (fault_signal_pending(fault, regs)) return; @@ -146,16 +149,7 @@ good_area: 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) - current->maj_flt++; - else - current->min_flt++; if (fault & VM_FAULT_RETRY) { flags |= FAULT_FLAG_TRIED; _
