The patch titled
Subject: mm/arm: use general page fault accounting
has been added to the -mm tree. Its filename is
mm-arm-use-general-page-fault-accounting.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-arm-use-general-page-fault-accounting.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-arm-use-general-page-fault-accounting.patch
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there every 3-4 working days
------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/arm: 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. To do this, we need to pass
the pt_regs pointer into __do_page_fault().
Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries,
by moving it before taking mmap_sem.
Link: http://lkml.kernel.org/r/20200707225021.200906-5-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm/mm/fault.c | 25 ++++++-------------------
1 file changed, 6 insertions(+), 19 deletions(-)
--- a/arch/arm/mm/fault.c~mm-arm-use-general-page-fault-accounting
+++ a/arch/arm/mm/fault.c
@@ -202,7 +202,8 @@ static inline bool access_error(unsigned
static vm_fault_t __kprobes
__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
- unsigned int flags, struct task_struct *tsk)
+ unsigned int flags, struct task_struct *tsk,
+ struct pt_regs *regs)
{
struct vm_area_struct *vma;
vm_fault_t fault;
@@ -224,7 +225,7 @@ good_area:
goto out;
}
- return handle_mm_fault(vma, addr & PAGE_MASK, flags, NULL);
+ return handle_mm_fault(vma, addr & PAGE_MASK, flags, regs);
check_stack:
/* Don't allow expansion below FIRST_USER_ADDRESS */
@@ -266,6 +267,8 @@ do_page_fault(unsigned long addr, unsign
if ((fsr & FSR_WRITE) && !(fsr & FSR_CM))
flags |= FAULT_FLAG_WRITE;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
+
/*
* As per x86, we may deadlock here. However, since the kernel only
* validly references user space from well defined areas of the code,
@@ -290,7 +293,7 @@ retry:
#endif
}
- fault = __do_page_fault(mm, addr, fsr, flags, tsk);
+ fault = __do_page_fault(mm, addr, fsr, flags, tsk, regs);
/* If we need to retry but a fatal signal is pending, handle the
* signal first. We do not need to release the mmap_lock because
@@ -302,23 +305,7 @@ retry:
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;
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-do-page-fault-accounting-in-handle_mm_fault.patch
mm-alpha-use-general-page-fault-accounting.patch
mm-arc-use-general-page-fault-accounting.patch
mm-arm-use-general-page-fault-accounting.patch
mm-arm64-use-general-page-fault-accounting.patch
mm-csky-use-general-page-fault-accounting.patch
mm-hexagon-use-general-page-fault-accounting.patch
mm-ia64-use-general-page-fault-accounting.patch
mm-m68k-use-general-page-fault-accounting.patch
mm-microblaze-use-general-page-fault-accounting.patch
mm-mips-use-general-page-fault-accounting.patch
mm-nds32-use-general-page-fault-accounting.patch
mm-nios2-use-general-page-fault-accounting.patch
mm-openrisc-use-general-page-fault-accounting.patch
mm-parisc-use-general-page-fault-accounting.patch
mm-powerpc-use-general-page-fault-accounting.patch
mm-riscv-use-general-page-fault-accounting.patch
mm-s390-use-general-page-fault-accounting.patch
mm-sh-use-general-page-fault-accounting.patch
mm-sparc32-use-general-page-fault-accounting.patch
mm-sparc64-use-general-page-fault-accounting.patch
mm-x86-use-general-page-fault-accounting.patch
mm-xtensa-use-general-page-fault-accounting.patch
mm-clean-up-the-last-pieces-of-page-fault-accountings.patch
mm-gup-remove-task_struct-pointer-for-all-gup-code.patch
