linux-kernel - [PATCH 07/26] mm/hexagon: Use general page fault accounting

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Message-Id: <20200619160538.8641-8-peterx@redhat.com>
Date:   Fri, 19 Jun 2020 12:05:19 -0400
From:   Peter Xu <peterx@...hat.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     Gerald Schaefer <gerald.schaefer@...ibm.com>, peterx@...hat.com,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Will Deacon <will@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Brian Cain <bcain@...eaurora.org>,
        linux-hexagon@...r.kernel.org
Subject: [PATCH 07/26] mm/hexagon: 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.

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: Brian Cain <bcain@...eaurora.org>
CC: linux-hexagon@...r.kernel.org
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 arch/hexagon/mm/vm_fault.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c
index f04cd0a6d905..1b1802f30862 100644
--- a/arch/hexagon/mm/vm_fault.c
+++ b/arch/hexagon/mm/vm_fault.c
@@ -19,6 +19,7 @@
 #include <linux/signal.h>
 #include <linux/extable.h>
 #include <linux/hardirq.h>
+#include <linux/perf_event.h>
 
 /*
  * Decode of hardware exception sends us to one of several
@@ -54,6 +55,8 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
 
 	if (user_mode(regs))
 		flags |= FAULT_FLAG_USER;
+
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 retry:
 	down_read(&mm->mmap_sem);
 	vma = find_vma(mm, address);
@@ -89,7 +92,7 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
 		break;
 	}
 
-	fault = handle_mm_fault(vma, address, flags, NULL);
+	fault = handle_mm_fault(vma, address, flags, regs);
 
 	if (fault_signal_pending(fault, regs))
 		return;
@@ -97,10 +100,6 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
 	/* The most common case -- we are done. */
 	if (likely(!(fault & VM_FAULT_ERROR))) {
 		if (flags & FAULT_FLAG_ALLOW_RETRY) {
-			if (fault & VM_FAULT_MAJOR)
-				current->maj_flt++;
-			else
-				current->min_flt++;
 			if (fault & VM_FAULT_RETRY) {
 				flags |= FAULT_FLAG_TRIED;
 				goto retry;
-- 
2.26.2