linux-kernel - [PATCH 20/25] mm/sh: Use mm_fault

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Date:   Mon, 15 Jun 2020 18:23:06 -0400
From:   Peter Xu <peterx@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     Peter Xu <peterx@...hat.com>,
        Gerald Schaefer <gerald.schaefer@...ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>, linux-sh@...r.kernel.org
Subject: [PATCH 20/25] mm/sh: 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.

CC: Yoshinori Sato <ysato@...rs.sourceforge.jp>
CC: Rich Felker <dalias@...c.org>
CC: linux-sh@...r.kernel.org
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 arch/sh/mm/fault.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index 5f23d7907597..06b232973488 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -379,7 +379,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	struct task_struct *tsk;
 	struct mm_struct *mm;
 	struct vm_area_struct * vma;
-	vm_fault_t fault;
+	vm_fault_t fault, major = 0;
 	unsigned int flags = FAULT_FLAG_DEFAULT;
 
 	tsk = current;
@@ -412,8 +412,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	if ((regs->sr & SR_IMASK) != SR_IMASK)
 		local_irq_enable();
 
-	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
-
 	/*
 	 * If we're in an interrupt, have no user context or are running
 	 * with pagefaults disabled then we must not take the fault:
@@ -465,21 +463,13 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	 * the fault.
 	 */
 	fault = handle_mm_fault(vma, address, flags);
+	major |= fault & VM_FAULT_MAJOR;
 
 	if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
 		if (mm_fault_error(regs, error_code, address, fault))
 			return;
 
 	if (flags & FAULT_FLAG_ALLOW_RETRY) {
-		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 (fault & VM_FAULT_RETRY) {
 			flags |= FAULT_FLAG_TRIED;
 
@@ -493,4 +483,5 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	}
 
 	up_read(&mm->mmap_sem);
+	mm_fault_accounting(tsk, regs, address, major);
 }
-- 
2.26.2