[PATCH v5 11/25] mm/mips: Use general page fault accounting

[Peter Xu]

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.

Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries, by
moving it before taking mmap_sem.

CC: Thomas Bogendoerfer <tsbog...@alpha.franken.de>
CC: linux-m...@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbog...@alpha.franken.de>
Signed-off-by: Peter Xu <pet...@redhat.com>
---
 arch/mips/mm/fault.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
index b1db39784db9..7c871b14e74a 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -96,6 +96,8 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, 
unsigned long write,
 
        if (user_mode(regs))
                flags |= FAULT_FLAG_USER;
+
+       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 retry:
        mmap_read_lock(mm);
        vma = find_vma(mm, address);
@@ -152,12 +154,11 @@ static void __kprobes __do_page_fault(struct pt_regs 
*regs, unsigned long write,
         * 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;
 
-       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
        if (unlikely(fault & VM_FAULT_ERROR)) {
                if (fault & VM_FAULT_OOM)
                        goto out_of_memory;
@@ -168,15 +169,6 @@ static void __kprobes __do_page_fault(struct pt_regs 
*regs, unsigned long write,
                BUG();
        }
        if (flags & FAULT_FLAG_ALLOW_RETRY) {
-               if (fault & VM_FAULT_MAJOR) {
-                       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
-                                                 regs, address);
-                       tsk->maj_flt++;
-               } else {
-                       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
-                                                 regs, address);
-                       tsk->min_flt++;
-               }
                if (fault & VM_FAULT_RETRY) {
                        flags |= FAULT_FLAG_TRIED;
 
-- 
2.26.2