[PATCH v5 23/25] mm/xtensa: Use general page fault accounting

From: Peter Xu <peterx@redhat.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	peterx@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
	Will Deacon <will@kernel.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	David Rientjes <rientjes@google.com>,
	John Hubbard <jhubbard@nvidia.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Chris Zankel <chris@zankel.net>,
	Max Filippov <jcmvbkbc@gmail.com>,
	linux-xtensa@linux-xtensa.org
Subject: [PATCH v5 23/25] mm/xtensa: Use general page fault accounting
Date: Tue,  7 Jul 2020 18:50:19 -0400	[thread overview]
Message-ID: <20200707225021.200906-24-peterx@redhat.com> (raw)
In-Reply-To: <20200707225021.200906-1-peterx@redhat.com>

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.

Remove the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] perf events because it's now
also done in handle_mm_fault().

Move the PERF_COUNT_SW_PAGE_FAULTS event higher before taking mmap_sem for the
fault, then it'll match with the rest of the archs.

CC: Chris Zankel <chris@zankel.net>
CC: Max Filippov <jcmvbkbc@gmail.com>
CC: linux-xtensa@linux-xtensa.org
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 arch/xtensa/mm/fault.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c
index e72c8c1359a6..7666408ce12a 100644
--- a/arch/xtensa/mm/fault.c
+++ b/arch/xtensa/mm/fault.c
@@ -72,6 +72,9 @@ void do_page_fault(struct pt_regs *regs)
 
 	if (user_mode(regs))
 		flags |= FAULT_FLAG_USER;
+
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+
 retry:
 	mmap_read_lock(mm);
 	vma = find_vma(mm, address);
@@ -107,7 +110,7 @@ void do_page_fault(struct pt_regs *regs)
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
-	fault = handle_mm_fault(vma, address, flags, NULL);
+	fault = handle_mm_fault(vma, address, flags, regs);
 
 	if (fault_signal_pending(fault, regs))
 		return;
@@ -122,10 +125,6 @@ void do_page_fault(struct pt_regs *regs)
 		BUG();
 	}
 	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;
 
@@ -139,12 +138,6 @@ void do_page_fault(struct pt_regs *regs)
 	}
 
 	mmap_read_unlock(mm);
-	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
-	if (flags & VM_FAULT_MAJOR)
-		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address);
-	else
-		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address);
-
 	return;
 
 	/* Something tried to access memory that isn't in our memory map..
-- 
2.26.2

