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: Vineet Gupta <vgu...@synopsys.com>
CC: linux-snps-arc@lists.infradead.org
Signed-off-by: Peter Xu <pet...@redhat.com>
---
 arch/arc/mm/fault.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index 587dea524e6b..f5657cb68e4f 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -105,6 +105,7 @@ void do_page_fault(unsigned long address, struct pt_regs 
*regs)
        if (write)
                flags |= FAULT_FLAG_WRITE;
 
+       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 retry:
        mmap_read_lock(mm);
 
@@ -130,7 +131,7 @@ void do_page_fault(unsigned long address, struct pt_regs 
*regs)
                goto bad_area;
        }
 
-       fault = handle_mm_fault(vma, address, flags, NULL);
+       fault = handle_mm_fault(vma, address, flags, regs);
 
        /* Quick path to respond to signals */
        if (fault_signal_pending(fault, regs)) {
@@ -155,22 +156,9 @@ void do_page_fault(unsigned long address, struct pt_regs 
*regs)
         * Major/minor page fault accounting
         * (in case of retry we only land here once)
         */
-       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
-
-       if (likely(!(fault & VM_FAULT_ERROR))) {
-               if (fault & VM_FAULT_MAJOR) {
-                       tsk->maj_flt++;
-                       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
-                                     regs, address);
-               } else {
-                       tsk->min_flt++;
-                       perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
-                                     regs, address);
-               }
-
+       if (likely(!(fault & VM_FAULT_ERROR)))
                /* Normal return path: fault Handled Gracefully */
                return;
-       }
 
        if (!user_mode(regs))
                goto no_context;
-- 
2.26.2


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