linux-kernel - [PATCH 12/25] mm/mips: Use mm_fault

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Date:   Mon, 15 Jun 2020 18:15:54 -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>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        linux-mips@...r.kernel.org
Subject: [PATCH 12/25] mm/mips: 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.
Since at it, move the accouting out of mmap_sem because not needed.

CC: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
CC: linux-mips@...r.kernel.org
Signed-off-by: Peter Xu <peterx@...hat.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 f8d62cd83b36..0b937fb12614 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -43,7 +43,7 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
 	struct mm_struct *mm = tsk->mm;
 	const int field = sizeof(unsigned long) * 2;
 	int si_code;
-	vm_fault_t fault;
+	vm_fault_t fault, major = 0;
 	unsigned int flags = FAULT_FLAG_DEFAULT;
 
 	static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
@@ -153,11 +153,11 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
 	 * the fault.
 	 */
 	fault = handle_mm_fault(vma, address, flags);
+	major |= fault & VM_FAULT_MAJOR;
 
 	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 +168,6 @@ 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;
 
@@ -191,6 +182,7 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
 	}
 
 	up_read(&mm->mmap_sem);
+	mm_fault_accounting(tsk, regs, address, major);
 	return;
 
 /*
-- 
2.26.2