From: Tejun Heo <tj@kernel.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Christoph Lameter <cl@linux.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] percpu: improve generic percpu modify-return implementation
Date: Thu, 22 Sep 2016 12:07:49 -0400 [thread overview]
Message-ID: <20160922160749.GD1892@htj.duckdns.org> (raw)
In-Reply-To: <20160922143500.21809b98@roar.ozlabs.ibm.com>
Hello,
On Thu, Sep 22, 2016 at 02:35:00PM +1000, Nicholas Piggin wrote:
> Well thank you, how about you?
Heh, can't complain. Hope to see you around sometime. It's been
forever.
> Trying a new mail client, sorry. It *seems* to be working now, how's
> this?
Hmm... Still encoded.
> From d0cb9052d6f4c31d24f999b7b0cecb34681eee9b Mon Sep 17 00:00:00 2001
> From: Nicholas Piggin <npiggin@gmail.com>
> Date: Wed, 21 Sep 2016 18:23:43 +1000
> Subject: [PATCH] percpu: improve generic percpu modify-return implementations
>
> Some architectures require an additional load to find the address of
> percpu pointers. In some implemenatations, the C aliasing rules do not
> allow the result of that load to be kept over the store that modifies
> the percpu variable, which causes additional loads.
>
> Work around this by finding the pointer first, then operating on that.
>
> It's also possible to mark things as restrict and those kind of games,
> but that can require larger and arch specific changes.
QP-decoded and applied to percpu/for-4.9.
Thanks.
--
tejun
next prev parent reply other threads:[~2016-09-22 16:07 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-21 8:51 [PATCH] percpu: improve generic percpu modify-return implementation Nicholas Piggin
2016-09-21 8:51 ` Nicholas Piggin
2016-09-21 10:25 ` kbuild test robot
2016-09-21 10:25 ` kbuild test robot
2016-09-21 10:30 ` kbuild test robot
2016-09-21 10:30 ` kbuild test robot
2016-09-21 10:30 ` kbuild test robot
2016-09-21 10:30 ` kbuild test robot
2016-09-21 10:57 ` Nicholas Piggin
2016-09-21 14:23 ` Tejun Heo
2016-09-21 14:23 ` Tejun Heo
2016-09-21 20:16 ` Christoph Lameter
2016-09-21 20:16 ` Christoph Lameter
2016-09-22 4:42 ` Nicholas Piggin
2016-09-22 4:35 ` Nicholas Piggin
2016-09-22 4:35 ` Nicholas Piggin
2016-09-22 16:07 ` Tejun Heo [this message]
2016-09-22 16:07 ` Tejun Heo
2016-09-23 7:33 ` Nicholas Piggin
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