| Message ID | 20200630204514.38711-1-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: Page fault accounting cleanups | expand |
On Tue, Jun 30, 2020 at 04:45:14PM -0400, Peter Xu 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. To do this, we pass pt_regs pointer into __do_page_fault(). > > CC: Catalin Marinas <catalin.marinas@arm.com> > CC: Will Deacon <will@kernel.org> > CC: linux-arm-kernel@lists.infradead.org > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > arch/arm64/mm/fault.c | 29 ++++++----------------------- > 1 file changed, 6 insertions(+), 23 deletions(-) > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index be29f4076fe3..f07333e86c2f 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -404,7 +404,8 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re > #define VM_FAULT_BADACCESS 0x020000 > > static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, > - unsigned int mm_flags, unsigned long vm_flags) > + unsigned int mm_flags, unsigned long vm_flags, > + struct pt_regs *regs) > { > struct vm_area_struct *vma = find_vma(mm, addr); > > @@ -428,7 +429,7 @@ static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, > */ > if (!(vma->vm_flags & vm_flags)) > return VM_FAULT_BADACCESS; > - return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, NULL); > + return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, regs); > } > > static bool is_el0_instruction_abort(unsigned int esr) > @@ -450,7 +451,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, > { > const struct fault_info *inf; > struct mm_struct *mm = current->mm; > - vm_fault_t fault, major = 0; > + vm_fault_t fault; > unsigned long vm_flags = VM_ACCESS_FLAGS; > unsigned int mm_flags = FAULT_FLAG_DEFAULT; > > @@ -516,8 +517,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, > #endif > } > > - fault = __do_page_fault(mm, addr, mm_flags, vm_flags); > - major |= fault & VM_FAULT_MAJOR; > + fault = __do_page_fault(mm, addr, mm_flags, vm_flags, regs); > > /* Quick path to respond to signals */ > if (fault_signal_pending(fault, regs)) { > @@ -538,25 +538,8 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, > * Handle the "normal" (no error) case first. > */ > if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | > - VM_FAULT_BADACCESS)))) { > - /* > - * Major/minor page fault accounting is only done > - * once. If we go through a retry, it is extremely > - * likely that the page will be found in page cache at > - * that point. > - */ > - if (major) { > - current->maj_flt++; > - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, > - addr); > - } else { > - current->min_flt++; > - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, > - addr); > - } > - > + VM_FAULT_BADACCESS)))) > return 0; > - } Thanks, looks good to me: Acked-by: Will Deacon <will@kernel.org> Will
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index be29f4076fe3..f07333e86c2f 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -404,7 +404,8 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re #define VM_FAULT_BADACCESS 0x020000 static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, - unsigned int mm_flags, unsigned long vm_flags) + unsigned int mm_flags, unsigned long vm_flags, + struct pt_regs *regs) { struct vm_area_struct *vma = find_vma(mm, addr); @@ -428,7 +429,7 @@ static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, */ if (!(vma->vm_flags & vm_flags)) return VM_FAULT_BADACCESS; - return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, NULL); + return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, regs); } static bool is_el0_instruction_abort(unsigned int esr) @@ -450,7 +451,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, { const struct fault_info *inf; struct mm_struct *mm = current->mm; - vm_fault_t fault, major = 0; + vm_fault_t fault; unsigned long vm_flags = VM_ACCESS_FLAGS; unsigned int mm_flags = FAULT_FLAG_DEFAULT; @@ -516,8 +517,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, #endif } - fault = __do_page_fault(mm, addr, mm_flags, vm_flags); - major |= fault & VM_FAULT_MAJOR; + fault = __do_page_fault(mm, addr, mm_flags, vm_flags, regs); /* Quick path to respond to signals */ if (fault_signal_pending(fault, regs)) { @@ -538,25 +538,8 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, * Handle the "normal" (no error) case first. */ if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | - VM_FAULT_BADACCESS)))) { - /* - * Major/minor page fault accounting is only done - * once. If we go through a retry, it is extremely - * likely that the page will be found in page cache at - * that point. - */ - if (major) { - current->maj_flt++; - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, - addr); - } else { - current->min_flt++; - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, - addr); - } - + VM_FAULT_BADACCESS)))) return 0; - } /* * If we are in kernel mode at this point, we have no context to
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. To do this, we pass pt_regs pointer into __do_page_fault(). CC: Catalin Marinas <catalin.marinas@arm.com> CC: Will Deacon <will@kernel.org> CC: linux-arm-kernel@lists.infradead.org Signed-off-by: Peter Xu <peterx@redhat.com> --- arch/arm64/mm/fault.c | 29 ++++++----------------------- 1 file changed, 6 insertions(+), 23 deletions(-)