mm/mips: Use general page fault accounting

PATCH Superseded Peter Xu 1 participant 1 message Jun 30, 2020

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Memory management MIPS

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Peter Xu

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2020-06-30 20:45 UTC #0 lore raw

PATCH v4 11/26 mm/mips: 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.

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

CC Thomas Bogendoerfer <[email protected]>

CC [email protected]

Acked-by Thomas Bogendoerfer <[email protected]>

Signed-off-by Peter Xu <[email protected]>

---
 arch/mips/mm/fault.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

arch/mips/mm/fault.c +3 ~~-11~~

index b1db39784db9..7c871b14e74a 100644
@@ -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;

Signature · 1 line

2.26.2