From: Michael Ellerman <mpe@ellerman.id.au>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Peter Xu <peterx@redhat.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
openrisc@lists.librecores.org,
linux-arch <linux-arch@vger.kernel.org>,
Alexander Gordeev <agordeev@linux.ibm.com>,
linux-s390 <linux-s390@vger.kernel.org>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 00/25] mm: Page fault accounting cleanups
Date: Wed, 17 Jun 2020 10:55:14 +1000 [thread overview]
Message-ID: <87imfqecjx.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <CAHk-=wiTjaXHu+uxMi0xCZQOm4KVr0MucECAK=Zm4p4YZZ1XEg@mail.gmail.com>
Linus Torvalds <torvalds@linux-foundation.org> writes:
> On Mon, Jun 15, 2020 at 3:16 PM Peter Xu <peterx@redhat.com> wrote:
>> This series tries to address all of them by introducing mm_fault_accounting()
>> first, so that we move all the page fault accounting into the common code base,
>> then call it properly from arch pf handlers just like handle_mm_fault().
>
> Hmm.
>
> So having looked at this a bit more, I'd actually like to go even
> further, and just get rid of the per-architecture code _entirely_.
<snip>
> One detail worth noting: I do wonder if we should put the
>
> perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
>
> just in the arch code at the top of the fault handling, and consider
> it entirely unrelated to the major/minor fault handling. The
> major/minor faults fundamnetally are about successes. But the plain
> PERF_COUNT_SW_PAGE_FAULTS could be about things that fail, including
> things that never even get to this point at all.
Yeah I think we should keep it in the arch code at roughly the top.
If it's moved to the end you could have a process spinning taking bad
page faults (and fixing them up), and see no sign of it from the perf
page fault counters.
cheers
next prev parent reply other threads:[~2020-06-17 0:54 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
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 [this message]
2020-06-17 8:04 ` Will Deacon
2020-06-17 16:10 ` Peter Xu
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