mm/m68k: 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().

Signed-off-by: Peter Xu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

Author: xzpeter

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>
@@ -84,6 +85,8 @@ 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:
 	mmap_read_lock(mm);
 
@@ -134,7 +137,7 @@ 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))
@@ -150,16 +153,7 @@ 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;