From: Will Deacon <will@kernel.org>
To: Peter Xu <peterx@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 06/25] mm/arm64: Use mm_fault_accounting()
Date: Tue, 16 Jun 2020 08:43:08 +0100 [thread overview]
Message-ID: <20200616074307.GA1637@willie-the-truck> (raw)
In-Reply-To: <20200615221607.7764-7-peterx@redhat.com>
On Mon, Jun 15, 2020 at 06:15:48PM -0400, Peter Xu wrote:
> Use the new mm_fault_accounting() helper for page fault accounting.
>
> 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 | 17 ++---------------
> 1 file changed, 2 insertions(+), 15 deletions(-)
>
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index c9cedc0432d2..09af7d7a60ec 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -484,8 +484,6 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
> addr, esr, regs);
> }
>
> - 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,
> @@ -535,20 +533,9 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
> 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.
> + * once.
> */
> - 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);
> - }
> -
> + mm_fault_accounting(current, regs, address, major);
Please can you explain why it's ok to move the PERF_COUNT_SW_PAGE_FAULTS
update like this? Seems like a user-visible change to me, so some
justification would really help.
Will
next prev parent reply other threads:[~2020-06-16 7:43 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 22:15 [PATCH 00/25] mm: Page fault accounting cleanups Peter Xu
2020-06-15 22:15 ` [PATCH 01/25] mm/um: Fix extra accounting for page fault retries Peter Xu
2020-06-15 22:15 ` [PATCH 02/25] mm: Introduce mm_fault_accounting() Peter Xu
2020-06-15 22:32 ` Linus Torvalds
2020-06-15 23:19 ` Peter Xu
2020-06-16 19:00 ` Andrew Morton
2020-06-17 16:26 ` Peter Xu
2020-06-15 22:15 ` [PATCH 03/25] mm/alpha: Use mm_fault_accounting() Peter Xu
2020-06-15 22:15 ` [PATCH 04/25] mm/arc: " Peter Xu
2020-06-15 22:15 ` [PATCH 05/25] mm/arm: " Peter Xu
2020-06-15 22:15 ` [PATCH 06/25] mm/arm64: " Peter Xu
2020-06-16 7:43 ` Will Deacon [this message]
2020-06-16 15:59 ` Peter Xu
2020-06-15 22:15 ` [PATCH 07/25] mm/csky: " Peter Xu
2020-06-17 7:04 ` Guo Ren
2020-06-17 15:49 ` Peter Xu
2020-06-17 17:53 ` Linus Torvalds
2020-06-17 19:58 ` Peter Xu
2020-06-17 20:15 ` Linus Torvalds
2020-06-18 14:38 ` Peter Xu
2020-06-18 17:15 ` Linus Torvalds
2020-06-18 21:24 ` Peter Xu
2020-06-18 22:28 ` Peter Xu
2020-06-18 22:59 ` Linus Torvalds
2020-06-15 22:15 ` [PATCH 08/25] mm/hexagon: " Peter Xu
2020-06-15 22:15 ` [PATCH 09/25] mm/ia64: " Peter Xu
2020-06-15 22:15 ` [PATCH 10/25] mm/m68k: " Peter Xu
2020-06-15 22:15 ` [PATCH 11/25] mm/microblaze: " Peter Xu
2020-06-15 22:15 ` [PATCH 12/25] mm/mips: " Peter Xu
2020-06-15 22:15 ` [PATCH 13/25] mm/nds32: " Peter Xu
2020-06-17 1:05 ` Greentime Hu
2020-06-15 22:15 ` [PATCH 14/25] mm/nios2: " Peter Xu
2020-06-15 22:15 ` [PATCH 15/25] mm/openrisc: " Peter Xu
2020-06-16 18:11 ` Stafford Horne
2020-06-15 22:15 ` [PATCH 16/25] mm/parisc: " Peter Xu
2020-06-15 22:15 ` [PATCH 17/25] mm/powerpc: " Peter Xu
2020-06-15 22:16 ` [PATCH 18/25] mm/riscv: " Peter Xu
2020-06-18 23:49 ` Palmer Dabbelt
2020-06-19 0:12 ` Peter Xu
2020-06-15 22:23 ` [PATCH 19/25] mm/s390: " Peter Xu
2020-06-16 15:59 ` Alexander Gordeev
2020-06-16 16:35 ` Peter Xu
2020-06-17 6:19 ` Christian Borntraeger
2020-06-17 16:06 ` Peter Xu
2020-06-17 16:14 ` Christian Borntraeger
2020-06-17 16:44 ` Peter Xu
2020-06-15 22:23 ` [PATCH 20/25] mm/sh: " Peter Xu
2020-07-20 21:25 ` Rich Felker
2020-07-20 22:05 ` Peter Xu
2020-06-15 22:23 ` [PATCH 21/25] mm/sparc32: " Peter Xu
2020-06-15 22:23 ` [PATCH 22/25] mm/sparc64: " Peter Xu
2020-06-15 22:23 ` [PATCH 23/25] mm/unicore32: " Peter Xu
2020-06-15 22:23 ` [PATCH 24/25] mm/x86: " Peter Xu
2020-06-15 22:23 ` [PATCH 25/25] mm/xtensa: " Peter Xu
2020-06-15 23:13 ` Max Filippov
2020-06-16 18:55 ` [PATCH 00/25] mm: Page fault accounting cleanups Linus Torvalds
2020-06-16 21:03 ` Peter Xu
2020-06-17 0:55 ` Michael Ellerman
2020-06-17 8:04 ` Will Deacon
2020-06-17 16:10 ` Peter Xu
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