Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20190310183051.87303-1-cai@lca.pw> <20190311035815.kq7ftc6vphy6vwen@linux-r8p5>
 <20190311122100.GF22862@mellanox.com> <1552312822.7087.11.camel@lca.pw>
In-Reply-To: <1552312822.7087.11.camel@lca.pw>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 11 Mar 2019 15:20:04 +0100
Message-ID: <CAK8P3a0QB7+oPz4sfbW_g2EGZZmC=LMEnkMNLCW_FD=fEZoQPA@mail.gmail.com>
Subject: Re: [PATCH] mm/debug: add a cast to u64 for atomic64_read()
To:     Qian Cai <cai@lca.pw>
Cc:     Jason Gunthorpe <jgg@mellanox.com>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Mark Rutland <mark.rutland@arm.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Mar 11, 2019 at 3:00 PM Qian Cai <cai@lca.pw> wrote:
>
> On Mon, 2019-03-11 at 12:21 +0000, Jason Gunthorpe wrote:
> > On Sun, Mar 10, 2019 at 08:58:15PM -0700, Davidlohr Bueso wrote:
> > > On Sun, 10 Mar 2019, Qian Cai wrote:
> >
> > Not saying this patch shouldn't go ahead..
> >
> > But is there a special reason the atomic64*'s on ppc don't use the u64
> > type like other archs? Seems like a better thing to fix than adding
> > casts all over the place.
> >
>
> A bit of history here,
>
> https://patchwork.kernel.org/patch/7344011/#15495901

Ah, I had already forgotten about that discussion.

At least the atomic_long part we discussed there has been resolved now
as part of commit b5d47ef9ea5c ("locking/atomics: Switch to generated
atomic-long").

Adding Mark Rutland to Cc, maybe he has some ideas of how to use
the infrastructure he added to use consistent types for atomic64()
on the remaining 64-bit architectures.

     Arnd