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From:   Peter Xu <peterx@redhat.com>
To:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc:     Peter Xu <peterx@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Gerald Schaefer <gerald.schaefer@de.ibm.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Will Deacon <will@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        "James E . J . Bottomley" <James.Bottomley@HansenPartnership.com>,
        Helge Deller <deller@gmx.de>, linux-parisc@vger.kernel.org
Subject: [PATCH 15/26] mm/parisc: Use general page fault accounting
Date:   Fri, 26 Jun 2020 18:36:20 -0400
Message-Id: <20200626223620.199717-1-peterx@redhat.com>
In-Reply-To: <20200626223130.199227-1-peterx@redhat.com>
References: <20200626223130.199227-1-peterx@redhat.com>
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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.

Add the missing PERF_COUNT_SW_PAGE_FAULTS perf events too.  Note, the other two
perf events (PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]) were done in handle_mm_fault().

CC: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
CC: Helge Deller <deller@gmx.de>
CC: linux-parisc@vger.kernel.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 arch/parisc/mm/fault.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index c10908ea8803..65661e22678e 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -18,6 +18,7 @@
 #include <linux/extable.h>
 #include <linux/uaccess.h>
 #include <linux/hugetlb.h>
+#include <linux/perf_event.h>
 
 #include <asm/traps.h>
 
@@ -281,6 +282,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
 	acc_type = parisc_acctyp(code, regs->iir);
 	if (acc_type & VM_WRITE)
 		flags |= FAULT_FLAG_WRITE;
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 retry:
 	down_read(&mm->mmap_sem);
 	vma = find_vma_prev(mm, address, &prev_vma);
@@ -302,7 +304,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
 	 * fault.
 	 */
 
-	fault = handle_mm_fault(vma, address, flags, NULL);
+	fault = handle_mm_fault(vma, address, flags, regs);
 
 	if (fault_signal_pending(fault, regs))
 		return;
@@ -323,10 +325,6 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
 		BUG();
 	}
 	if (flags & FAULT_FLAG_ALLOW_RETRY) {
-		if (fault & VM_FAULT_MAJOR)
-			current->maj_flt++;
-		else
-			current->min_flt++;
 		if (fault & VM_FAULT_RETRY) {
 			/*
 			 * No need to up_read(&mm->mmap_sem) as we would
-- 
2.26.2