From: Peter Xu <peterx@redhat.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
peterx@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>,
David Rientjes <rientjes@google.com>,
John Hubbard <jhubbard@nvidia.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Russell King <linux@armlinux.org.uk>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 04/25] mm/arm: Use general page fault accounting
Date: Tue, 7 Jul 2020 18:50:00 -0400 [thread overview]
Message-ID: <20200707225021.200906-5-peterx@redhat.com> (raw)
In-Reply-To: <20200707225021.200906-1-peterx@redhat.com>
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.
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 | 25 ++++++-------------------
1 file changed, 6 insertions(+), 19 deletions(-)
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 01a8e0f8fef7..efa402025031 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -202,7 +202,8 @@ static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
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 @@ __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
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, unsigned int fsr, struct pt_regs *regs)
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 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
#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 @@ 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;
--
2.26.2
next prev parent reply other threads:[~2020-07-07 22:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 22:49 [PATCH v5 00/25] mm: Page fault accounting cleanups Peter Xu
2020-07-07 22:49 ` [PATCH v5 01/25] mm: Do page fault accounting in handle_mm_fault Peter Xu
2020-07-07 22:49 ` [PATCH v5 02/25] mm/alpha: Use general page fault accounting Peter Xu
2020-07-07 22:49 ` [PATCH v5 03/25] mm/arc: " Peter Xu
2020-07-07 22:50 ` Peter Xu [this message]
2020-07-07 22:50 ` [PATCH v5 05/25] mm/arm64: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 06/25] mm/csky: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 07/25] mm/hexagon: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 08/25] mm/ia64: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 09/25] mm/m68k: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 10/25] mm/microblaze: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 11/25] mm/mips: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 12/25] mm/nds32: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 13/25] mm/nios2: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 14/25] mm/openrisc: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 15/25] mm/parisc: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 16/25] mm/powerpc: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 17/25] mm/riscv: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 18/25] mm/s390: " Peter Xu
2020-07-08 5:49 ` Alexander Gordeev
2020-07-08 14:30 ` Peter Xu
2020-07-07 22:50 ` [PATCH v5 19/25] mm/sh: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 20/25] mm/sparc32: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 21/25] mm/sparc64: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 22/25] mm/x86: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 23/25] mm/xtensa: " Peter Xu
2020-07-07 22:50 ` [PATCH v5 24/25] mm: Clean up the last pieces of page fault accountings Peter Xu
2020-07-07 22:50 ` [PATCH v5 25/25] mm/gup: Remove task_struct pointer for all gup code Peter Xu
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