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From:   Pekka Enberg <penberg@gmail.com>
Date:   Tue, 14 Jul 2020 18:12:14 +0300
Message-ID: <CAOJsxLHOMCtoty49+8u9+5EA2H76nE5-MAbyPSzP4gvYAfG+2A@mail.gmail.com>
Subject: Re: [PATCH 17/26] mm/riscv: Use general page fault accounting
To:     Palmer Dabbelt <palmer@dabbelt.com>
Cc:     Peter Xu <peterx@redhat.com>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Gerald Schaefer <gerald.schaefer@de.ibm.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Will Deacon <will@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-riscv <linux-riscv@lists.infradead.org>
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Hi Palmer,

On Sat, Jul 11, 2020 at 10:43 PM Palmer Dabbelt <palmer@dabbelt.com> wrote:
> This still slightly changes the accounting numbers, but I don't think it does
> so in a way that's meaningful enough to care about.  SIGBUS is the only one
> that might happen frequently enough to notice, I doubt anyone cares about
> whether faults are accounted for during OOM.

What do you mean?

AFAICT, this patch _fixes_ the accounting to be correct on page fault
restarts. I sent a patch to fix this up some time ago, but of course
this generic solutions is better:

http://lists.infradead.org/pipermail/linux-riscv/2020-June/000775.html

- Pekka