From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
peterx@redhat.com, John Hubbard <jhubbard@nvidia.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Will Deacon <will@kernel.org>, Nick Hu <nickhu@andestech.com>,
Greentime Hu <green.hu@gmail.com>,
Vincent Chen <deanbo422@gmail.com>
Subject: [PATCH v4 12/26] mm/nds32: Use general page fault accounting
Date: Tue, 30 Jun 2020 16:45:33 -0400 [thread overview]
Message-ID: <20200630204533.39053-1-peterx@redhat.com> (raw)
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.
Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries, by
moving it before taking mmap_sem.
CC: Nick Hu <nickhu@andestech.com>
CC: Greentime Hu <green.hu@gmail.com>
CC: Vincent Chen <deanbo422@gmail.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
arch/nds32/mm/fault.c | 19 +++----------------
1 file changed, 3 insertions(+), 16 deletions(-)
diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c
index d0ecc8fb5b23..f02524eb6d56 100644
--- a/arch/nds32/mm/fault.c
+++ b/arch/nds32/mm/fault.c
@@ -121,6 +121,8 @@ void do_page_fault(unsigned long entry, unsigned long addr,
if (unlikely(faulthandler_disabled() || !mm))
goto no_context;
+ 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,
@@ -206,7 +208,7 @@ void do_page_fault(unsigned long entry, unsigned long addr,
* the fault.
*/
- fault = handle_mm_fault(vma, addr, flags, NULL);
+ fault = handle_mm_fault(vma, addr, flags, regs);
/*
* If we need to retry but a fatal signal is pending, handle the
@@ -228,22 +230,7 @@ void do_page_fault(unsigned long entry, unsigned long addr,
goto bad_area;
}
- /*
- * 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 (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;
--
2.26.2
reply other threads:[~2020-06-30 20:45 UTC|newest]
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