2020-06-30 21:34:51

by Peter Xu

Subject: [PATCH v4 18/26] mm/s390: 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.

CC: Heiko Carstens <[email protected]>
CC: Vasily Gorbik <[email protected]>
CC: Christian Borntraeger <[email protected]>
CC: [email protected]
Signed-off-by: Peter Xu <[email protected]>
---
arch/s390/mm/fault.c | 16 +---------------
1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index fc14df0b4d6e..9aa201df2e94 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -478,7 +478,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access)
* 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)) {
fault = VM_FAULT_SIGNAL;
if (flags & FAULT_FLAG_RETRY_NOWAIT)
@@ -488,21 +488,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access)
if (unlikely(fault & VM_FAULT_ERROR))
goto out_up;

- /*
- * 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) {
- tsk->maj_flt++;
- 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);
- }
if (fault & VM_FAULT_RETRY) {
if (IS_ENABLED(CONFIG_PGSTE) && gmap &&
(flags & FAULT_FLAG_RETRY_NOWAIT)) {
--
2.26.2

2020-07-01 14:54:23

by Gerald Schaefer

Subject: Re: [PATCH v4 18/26] mm/s390: Use general page fault accounting

On Tue, 30 Jun 2020 16:45:48 -0400
Peter Xu <[email protected]> wrote:

> 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.
>
> CC: Heiko Carstens <[email protected]>
> CC: Vasily Gorbik <[email protected]>
> CC: Christian Borntraeger <[email protected]>
> CC: [email protected]
> Signed-off-by: Peter Xu <[email protected]>
> ---
> arch/s390/mm/fault.c | 16 +---------------
> 1 file changed, 1 insertion(+), 15 deletions(-)

Reviewed-by: Gerald Schaefer <[email protected]>
Acked-by: Gerald Schaefer <[email protected]>