linux-kernel - [PATCH v4 17/26] mm/riscv: Use general page fault accounting

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Message-Id: <20200630204545.39293-1-peterx@redhat.com>
Date:   Tue, 30 Jun 2020 16:45:45 -0400
From:   Peter Xu <peterx@...hat.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Andrew Morton <akpm@...ux-foundation.org>, peterx@...hat.com,
        John Hubbard <jhubbard@...dia.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Gerald Schaefer <gerald.schaefer@...ibm.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Will Deacon <will@...nel.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv@...ts.infradead.org
Subject: [PATCH v4 17/26] mm/riscv: 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.

CC: Paul Walmsley <paul.walmsley@...ive.com>
CC: Palmer Dabbelt <palmer@...belt.com>
CC: Albert Ou <aou@...s.berkeley.edu>
CC: linux-riscv@...ts.infradead.org
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 arch/riscv/mm/fault.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 50a952a68433..e72cec09d55b 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -110,7 +110,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
-	fault = handle_mm_fault(vma, addr, flags, NULL);
+	fault = handle_mm_fault(vma, addr, flags, regs);
 
 	/*
 	 * If we need to retry but a fatal signal is pending, handle the
@@ -128,21 +128,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 		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) {
-			tsk->maj_flt++;
-			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
-				      1, regs, addr);
-		} else {
-			tsk->min_flt++;
-			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
-				      1, regs, addr);
-		}
 		if (fault & VM_FAULT_RETRY) {
 			flags |= FAULT_FLAG_TRIED;
 
-- 
2.26.2