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From:   Mao Han <han_mao@c-sky.com>
To:     guoren@kernel.org
Cc:     linux-kernel@vger.kernel.org, Mao Han <han_mao@c-sky.com>
Subject: [PATCH 1/1] csky: add page fault perf event support
Date:   Thu, 18 Apr 2019 14:20:40 +0800
Message-Id: <46349332f41f16896afde240973764c385d78cd3.1555568371.git.han_mao@c-sky.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This patch add support for page fault count, major fault count
and minorfault count. Without this patch page faults are not
sampled for perf event.

 Performance counter stats for '/usr/lib/perf-test/callchain_test':
                 0      page-faults               #    0.000 K/sec

Signed-off-by: Mao Han <han_mao@c-sky.com>
---
 arch/csky/mm/fault.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
index e1725f8..d07141d 100644
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -17,6 +17,7 @@
 #include <linux/vt_kern.h>
 #include <linux/extable.h>
 #include <linux/uaccess.h>
+#include <linux/perf_event.h>
 
 #include <asm/hardirq.h>
 #include <asm/mmu_context.h>
@@ -106,6 +107,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
 		return;
 	}
 #endif
+
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 	/*
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
@@ -153,10 +156,15 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
 			goto bad_area;
 		BUG();
 	}
-	if (fault & VM_FAULT_MAJOR)
+	if (fault & VM_FAULT_MAJOR) {
 		tsk->maj_flt++;
-	else
+		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);
+	}
 
 	up_read(&mm->mmap_sem);
 	return;
-- 
2.7.4