2020-06-30 21:33:41

by Peter Xu

Subject: [PATCH v4 07/26] mm/hexagon: 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().

CC: Brian Cain <[email protected]>
CC: [email protected]
Signed-off-by: Peter Xu <[email protected]>
---
arch/hexagon/mm/vm_fault.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c
index f12f330e7946..ef32c5a84ff3 100644
--- a/arch/hexagon/mm/vm_fault.c
+++ b/arch/hexagon/mm/vm_fault.c
@@ -18,6 +18,7 @@
#include <linux/signal.h>
#include <linux/extable.h>
#include <linux/hardirq.h>
+#include <linux/perf_event.h>

/*
* Decode of hardware exception sends us to one of several
@@ -53,6 +54,8 @@ void do_page_fault(unsigned long address, long cause, 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);
@@ -88,7 +91,7 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
break;
}

- fault = handle_mm_fault(vma, address, flags, NULL);
+ fault = handle_mm_fault(vma, address, flags, regs);

if (fault_signal_pending(fault, regs))
return;
@@ -96,10 +99,6 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
/* The most common case -- we are done. */
if (likely(!(fault & VM_FAULT_ERROR))) {
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;
goto retry;
--
2.26.2

2020-06-30 22:58:07

by Brian Cain

Subject: RE: [PATCH v4 07/26] mm/hexagon: Use general page fault accounting

> -----Original Message-----
> From: [email protected] <linux-hexagon-
...

Acked-by: Brian Cain <[email protected]>

> CC: Brian Cain <[email protected]>
> CC: [email protected]
> Signed-off-by: Peter Xu <[email protected]>
> ---
> arch/hexagon/mm/vm_fault.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c
> index f12f330e7946..ef32c5a84ff3 100644
> --- a/arch/hexagon/mm/vm_fault.c
> +++ b/arch/hexagon/mm/vm_fault.c
> @@ -18,6 +18,7 @@
> #include <linux/signal.h>
> #include <linux/extable.h>
> #include <linux/hardirq.h>
> +#include <linux/perf_event.h>
>
> /*
> * Decode of hardware exception sends us to one of several @@ -53,6 +54,8
> @@ void do_page_fault(unsigned long address, long cause, 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);
> @@ -88,7 +91,7 @@ void do_page_fault(unsigned long address, long cause,
> struct pt_regs *regs)
> break;
> }
>
> - fault = handle_mm_fault(vma, address, flags, NULL);
> + fault = handle_mm_fault(vma, address, flags, regs);
>
> if (fault_signal_pending(fault, regs))
> return;
> @@ -96,10 +99,6 @@ void do_page_fault(unsigned long address, long cause,
> struct pt_regs *regs)
> /* The most common case -- we are done. */
> if (likely(!(fault & VM_FAULT_ERROR))) {
> 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;
> goto retry;
> --
> 2.26.2