[PATCH 09/26] mm/m68k: Use general page fault accounting

From: Peter Xu
Date: Fri Jun 26 2020 - 18:32:09 EST


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: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
CC: linux-m68k@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
arch/m68k/mm/fault.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index 2db38dfbc00c..983054d209bc 100644
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -12,6 +12,7 @@
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/uaccess.h>
+#include <linux/perf_event.h>

#include <asm/setup.h>
#include <asm/traps.h>
@@ -85,6 +86,8 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,

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);

@@ -135,7 +138,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
* the fault.
*/

- fault = handle_mm_fault(vma, address, flags, NULL);
+ fault = handle_mm_fault(vma, address, flags, regs);
pr_debug("handle_mm_fault returns %x\n", fault);

if (fault_signal_pending(fault, regs))
@@ -151,16 +154,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
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)
- current->maj_flt++;
- else
- current->min_flt++;
if (fault & VM_FAULT_RETRY) {
flags |= FAULT_FLAG_TRIED;

--
2.26.2