linux-kernel - [PATCH 04/25] mm/arc: Use mm_fault

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Message-Id: <20200615221607.7764-5-peterx@redhat.com>
Date:   Mon, 15 Jun 2020 18:15:46 -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>,
        Vineet Gupta <vgupta@...opsys.com>,
        linux-snps-arc@...ts.infradead.org
Subject: [PATCH 04/25] mm/arc: Use mm_fault_accounting()

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

The functional change here is that now we take the whole page fault as a major
fault as long as any of the retried page fault is a major fault.  Previously we
only considered the last fault.

CC: Vineet Gupta <vgupta@...opsys.com>
CC: linux-snps-arc@...ts.infradead.org
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 arch/arc/mm/fault.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index 92b339c7adba..bc89d4b9c59d 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -72,6 +72,7 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
 	int sig, si_code = SEGV_MAPERR;
 	unsigned int write = 0, exec = 0, mask;
 	vm_fault_t fault = VM_FAULT_SIGSEGV;	/* handle_mm_fault() output */
+	vm_fault_t major = 0;
 	unsigned int flags;			/* handle_mm_fault() input */
 
 	/*
@@ -132,6 +133,7 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
 	}
 
 	fault = handle_mm_fault(vma, address, flags);
+	major |= fault & VM_FAULT_MAJOR;
 
 	/* Quick path to respond to signals */
 	if (fault_signal_pending(fault, regs)) {
@@ -156,20 +158,9 @@ 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);
-		}
-
 		/* Normal return path: fault Handled Gracefully */
+		mm_fault_accounting(tsk, regs, address, major);
 		return;
 	}
 
-- 
2.26.2