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

From: Peter Xu
Date: Tue Jul 07 2020 - 18:51:11 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.

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@xxxxxxxxxx>
CC: Max Filippov <jcmvbkbc@xxxxxxxxx>
CC: linux-xtensa@xxxxxxxxxxxxxxxx
Acked-by: Max Filippov <jcmvbkbc@xxxxxxxxx>
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
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