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Subject[PATCH 05/25] mm/arm: Use mm_fault_accounting()
Date
Use the new mm_fault_accounting() helper for page fault accounting.

Avoid doing page fault accounting multiple times if the page fault is retried.
Meanwhile, take the page fault as a major fault as long as any of the retried
page fault is a major fault.

CC: Russell King <linux@armlinux.org.uk>
CC: Will Deacon <will@kernel.org>
CC: linux-arm-kernel@lists.infradead.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
arch/arm/mm/fault.c | 21 ++++-----------------
1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 2dd5c41cbb8d..92d4436e74da 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -240,7 +240,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
struct task_struct *tsk;
struct mm_struct *mm;
int sig, code;
- vm_fault_t fault;
+ vm_fault_t fault, major = 0;
unsigned int flags = FAULT_FLAG_DEFAULT;

if (kprobe_page_fault(regs, fsr))
@@ -290,6 +290,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
}

fault = __do_page_fault(mm, addr, fsr, flags, tsk);
+ major |= fault & VM_FAULT_MAJOR;

/* If we need to retry but a fatal signal is pending, handle the
* signal first. We do not need to release the mmap_sem because
@@ -301,23 +302,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
return 0;
}

- /*
- * 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.
- */
-
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
if (!(fault & VM_FAULT_ERROR) && flags & FAULT_FLAG_ALLOW_RETRY) {
- if (fault & VM_FAULT_MAJOR) {
- tsk->maj_flt++;
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
- regs, addr);
- } else {
- tsk->min_flt++;
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
- regs, addr);
- }
if (fault & VM_FAULT_RETRY) {
flags |= FAULT_FLAG_TRIED;
goto retry;
@@ -326,6 +311,8 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)

up_read(&mm->mmap_sem);

+ mm_fault_accounting(tsk, regs, addr, major);
+
/*
* Handle the "normal" case first - VM_FAULT_MAJOR
*/
--
2.26.2
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