From: Arnd Bergmann <arnd@arndb.de>
To: Jason Gunthorpe <jgg@mellanox.com>
Cc: Qian Cai <cai@lca.pw>,
"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>
Subject: Re: [PATCH] mm/debug: add a cast to u64 for atomic64_read()
Date: Mon, 11 Mar 2019 15:00:50 +0100 [thread overview]
Message-ID: <CAK8P3a1PpgjRKFemEi7mLuECh1srs8bbzoc07RSrFsx+febjaQ@mail.gmail.com> (raw)
In-Reply-To: <20190311122100.GF22862@mellanox.com>
On Mon, Mar 11, 2019 at 1:21 PM Jason Gunthorpe <jgg@mellanox.com> wrote:
> On Sun, Mar 10, 2019 at 08:58:15PM -0700, Davidlohr Bueso wrote:
> > On Sun, 10 Mar 2019, Qian Cai wrote:
> >
> > Acked-by: Davidlohr Bueso <dbueso@suse.de>
>
> 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.
Agreed in principle, but I'd note that it's not just ppc64, but almost all
64-bit architectures. x86-64 and arm64 changed over last year
from returning 'long' to 'long long', apparently as an unintended
side effect of commits 8bf705d13039 ("locking/atomic/x86: Switch
atomic.h to use atomic-instrumented.h") and c0df10812835 ("arm64,
locking/atomics: Use instrumented atomics").
It would be nice to just do the instrumented atomics on all 64-bit
architectures for consistency, but that would be a lot of work, and
would not actually give us additional instrumentation on most of them,
since they don't support KASAN (except s390).
Arnd
prev parent reply other threads:[~2019-03-11 14:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-10 18:30 [PATCH] mm/debug: add a cast to u64 for atomic64_read() Qian Cai
2019-03-11 3:58 ` Davidlohr Bueso
2019-03-11 12:21 ` Jason Gunthorpe
2019-03-11 14:00 ` Qian Cai
2019-03-11 14:20 ` Arnd Bergmann
2019-03-13 9:18 ` Peter Zijlstra
2019-03-13 13:46 ` Arnd Bergmann
2019-03-13 14:21 ` Peter Zijlstra
2019-03-13 14:24 ` Peter Zijlstra
2019-03-13 14:35 ` Mark Rutland
2019-03-13 14:57 ` Arnd Bergmann
2019-03-13 16:29 ` Mark Rutland
2019-03-11 14:00 ` Arnd Bergmann [this message]
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