linux-kernel - [PATCH 14/25] mm/nios2: Use mm_fault

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Date:   Mon, 15 Jun 2020 18:15:56 -0400
From:   Peter Xu <peterx@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Gerald Schaefer <gerald.schaefer@...ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>, peterx@...hat.com,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Ley Foon Tan <ley.foon.tan@...el.com>
Subject: [PATCH 14/25] mm/nios2: Use mm_fault_accounting()

Use the new mm_fault_accounting() helper for page fault accounting.

Avoid doing page fault accounting multiple times if the page fault is retried.
Also, the perf events for page faults will be accounted too when the config has
CONFIG_PERF_EVENTS defined.

CC: Ley Foon Tan <ley.foon.tan@...el.com>
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 arch/nios2/mm/fault.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c
index ec9d8a9c426f..48617960a07e 100644
--- a/arch/nios2/mm/fault.c
+++ b/arch/nios2/mm/fault.c
@@ -46,7 +46,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause,
 	struct task_struct *tsk = current;
 	struct mm_struct *mm = tsk->mm;
 	int code = SEGV_MAPERR;
-	vm_fault_t fault;
+	vm_fault_t fault, major = 0;
 	unsigned int flags = FAULT_FLAG_DEFAULT;
 
 	cause >>= 2;
@@ -132,6 +132,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause,
 	 * the fault.
 	 */
 	fault = handle_mm_fault(vma, address, flags);
+	major |= fault & VM_FAULT_MAJOR;
 
 	if (fault_signal_pending(fault, regs))
 		return;
@@ -146,16 +147,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause,
 		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;
 
@@ -170,6 +162,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause,
 	}
 
 	up_read(&mm->mmap_sem);
+	mm_fault_accounting(current, regs, address, major);
 	return;
 
 /*
-- 
2.26.2