From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marc Zyngier <marc.zyngier@arm.com>
Subject: Re: [PATCH v13 01/20] ARM64: Move PMU register related defines to
 asm/perf_event.h
Date: Mon, 29 Feb 2016 13:07:23 +0000
Message-ID: <56D4428B.5000505@arm.com>
References: <1456290520-10012-1-git-send-email-zhaoshenglong@huawei.com>
 <1456290520-10012-2-git-send-email-zhaoshenglong@huawei.com>
 <20160224175247.GE12471@arm.com> <56CE6098.8070001@huawei.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Cc: kvmarm@lists.cs.columbia.edu, christoffer.dall@linaro.org,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
	wei@redhat.com, cov@codeaurora.org, shannon.zhao@linaro.org,
	peter.huangpeng@huawei.com, hangaohuai@huawei.com
To: Shannon Zhao <zhaoshenglong@huawei.com>,
	Will Deacon <will.deacon@arm.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from foss.arm.com ([217.140.101.70]:44273 "EHLO foss.arm.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1750723AbcB2NH1 (ORCPT <rfc822;kvm@vger.kernel.org>);
	Mon, 29 Feb 2016 08:07:27 -0500
In-Reply-To: <56CE6098.8070001@huawei.com>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

Shannon,

On 25/02/16 02:02, Shannon Zhao wrote:
> 
> 
> On 2016/2/25 1:52, Will Deacon wrote:
>> On Wed, Feb 24, 2016 at 01:08:21PM +0800, Shannon Zhao wrote:
>>> From: Shannon Zhao <shannon.zhao@linaro.org>
>>>
>>> To use the ARMv8 PMU related register defines from the KVM code, we move
>>> the relevant definitions to asm/perf_event.h header file and rename them
>>> with prefix ARMV8_PMU_.
>>>
>>> Signed-off-by: Anup Patel <anup.patel@linaro.org>
>>> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
>>> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
>>> Reviewed-by: Andrew Jones <drjones@redhat.com>
>>> ---
>>>  arch/arm64/include/asm/perf_event.h | 35 +++++++++++++++++++
>>>  arch/arm64/kernel/perf_event.c      | 68 ++++++++++---------------------------
>>>  2 files changed, 52 insertions(+), 51 deletions(-)
>>
>> Looks fine to me, but we're going to get some truly horrible conflicts
>> in -next.
>>
>> I'm open to suggestions on the best way to handle this, but one way
>> would be:
>>
>>   1. Duplicate all the #defines privately in KVM (queue via kvm tree)
> This way seems not proper I think.
> 
>>   2. Rebase this patch onto my perf/updates branch [1] (queue via me)
> While to this series, it really relies on the perf_event.h to compile
> and test, so maybe for KVM-ARM and KVM maintainers it's not proper.
> 
>>   3. Patch at -rc1 dropping the #defines from (1) and moving to the new
>>      perf_event.h stuff
>>
> I vote for this way. Since the patch in [1] is small and nothing else
> relies on them, I think it would be simple to rebase them onto this series.
> 
>> Thoughts?
>>
> Anyway, there are only 3 lines which have conflicts. I'm not sure
> whether we could handle this when we merge them.

I think you're missing the point:

- We want both the arm64 perf and KVM trees to be easy to merge
- The conflicts are not that simple to resolve
- We want these conflicts to be solved before it hits Linus' tree

With that in mind, here's what I'm suggesting we merge as a first patch:

https://git.kernel.org/cgit/linux/kernel/git/kvmarm/kvmarm.git/commit/?h=queue&id=2029b4b02691ec6ebba3d281068e783353d7e108

Once this and the perf/updates branch are merged, we can add one last
patch reverting this hack and actually doing the renaming work (Will has
posted a resolution for most of the new things).

Thoughts?

	M.
-- 
Jazz is not dead. It just smells funny...