[PATCH 05/26] mm/arm64: Use general page fault accounting

Peter Xu
2020-06-19T16:07:22Z

retry happened. To do this, we pass pt_regs pointer into __do_page_fault().

CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will@kernel.org>
CC: linux-arm-kernel@lists.infradead.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
arch/arm64/mm/fault.c | 29 ++++++-----------------------
1 file changed, 6 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 5f6607b951b8..09b206521559 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -398,7 +398,8 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re
#define VM_FAULT_BADACCESS 0x020000

static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr,
- unsigned int mm_flags, unsigned long vm_flags)
+ unsigned int mm_flags, unsigned long vm_flags,
+ struct pt_regs *regs)
{
struct vm_area_struct *vma = find_vma(mm, addr);

@@ -422,7 +423,7 @@ static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr,
*/
if (!(vma->vm_flags & vm_flags))
return VM_FAULT_BADACCESS;
- return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, NULL);
+ return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, regs);
}

static bool is_el0_instruction_abort(unsigned int esr)
@@ -444,7 +445,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
{
const struct fault_info *inf;
struct mm_struct *mm = current->mm;
- vm_fault_t fault, major = 0;
+ vm_fault_t fault;
unsigned long vm_flags = VM_ACCESS_FLAGS;
unsigned int mm_flags = FAULT_FLAG_DEFAULT;

@@ -510,8 +511,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
#endif
}

- fault = __do_page_fault(mm, addr, mm_flags, vm_flags);
- major |= fault & VM_FAULT_MAJOR;
+ fault = __do_page_fault(mm, addr, mm_flags, vm_flags, regs);

/* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) {
@@ -532,25 +532,8 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
* Handle the "normal" (no error) case first.
*/
if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
- VM_FAULT_BADACCESS)))) {
- /*
- * Major/minor page fault accounting is only done
- * once. If we go through a retry, it is extremely
- * likely that the page will be found in page cache at
- * that point.
- */
- if (major) {
- current->maj_flt++;
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs,
- addr);
- } else {
- current->min_flt++;
- perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs,
- addr);
- }
-
+ VM_FAULT_BADACCESS))))
return 0;
- }

/*
* If we are in kernel mode at this point, we have no context to
--
2.26.2