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Date:   Mon, 11 Jan 2021 13:03:29 -0800 (PST)
From:   Hugh Dickins <hughd@google.com>
To:     Will Deacon <will@kernel.org>
cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Vinayak Menon <vinmenon@codeaurora.org>,
        Hugh Dickins <hughd@google.com>,
        Android Kernel Team <kernel-team@android.com>
Subject: Re: [PATCH v2 0/3] Create 'old' ptes for faultaround mappings on
 arm64 with hardware access flag
In-Reply-To: <20210111133007.GA7642@willie-the-truck>
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References: <20210108171517.5290-1-will@kernel.org> <CAHk-=wg3UkUdiTbqWFx3zBLXv9VJHuNZAa5QyDvXiSmD4gX94A@mail.gmail.com> <20210111133007.GA7642@willie-the-truck>
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On Mon, 11 Jan 2021, Will Deacon wrote:
> On Fri, Jan 08, 2021 at 11:34:08AM -0800, Linus Torvalds wrote:
> > On Fri, Jan 8, 2021 at 9:15 AM Will Deacon <will@kernel.org> wrote:
> > >
> > > The big difference in this version is that I have reworked it based on
> > > Kirill's patch which he posted as a follow-up to the original. However,
> > > I can't tell where we've landed on that -- Linus seemed to like it, but
> > > Hugh was less enthusiastic.
> > 
> > Yeah, I like it, but I have to admit that it had a disturbingly high
> > number of small details wrong for several versions. I hope you picked
> > up the final version of the code.
> 
> I picked the version from here:
> 
>   https://lore.kernel.org/r/20201229132819.najtavneutnf7ajp@box
> 
> and actually, I just noticed that willy spotted a typo in a comment, so
> I'll fix that locally as well as adding the above to a 'Link:' tag for
> reference.
> 
> > At the same time, I do think that the "disturbingly high number of
> > issues" was primarily exactly _because_ the old code was so
> > incomprehensible, and I think the end result is much cleaner, so I
> > still like it.

Just to report that I gave this v2 set a spin on a few (x86_64 and i386)
machines, and found nothing objectionable this time around.

And the things that I'm unenthusiastic about are exactly those details
that you and Kirill and Linus find unsatisfactory, but awkward to
eliminate: expect no new insights from me!

Hugh