From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wei Wang <wei.w.wang@intel.com>
Subject: Re: [PATCH v3 5/5] KVM/x86/lbr: lazy save the guest lbr stack
Date: Thu, 20 Sep 2018 20:58:16 +0800
Message-ID: <5BA39968.8030309@intel.com>
References: <1537437959-8751-1-git-send-email-wei.w.wang@intel.com> <1537437959-8751-6-git-send-email-wei.w.wang@intel.com> <20180920123753.GT24124@hirez.programming.kicks-ass.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        pbonzini@redhat.com, ak@linux.intel.com, kan.liang@intel.com,
        mingo@redhat.com, rkrcmar@redhat.com, like.xu@intel.com,
        jannh@google.com, arei.gonglei@huawei.com
To: Peter Zijlstra <peterz@infradead.org>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20180920123753.GT24124@hirez.programming.kicks-ass.net>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On 09/20/2018 08:37 PM, Peter Zijlstra wrote:
> On Thu, Sep 20, 2018 at 06:05:59PM +0800, Wei Wang wrote:
>>   /**
>> + * lbr_select_user_callstack - check if the user callstack mode is set
>> + *
>> + * @lbr_select: the lbr select msr
>> + *
>> + * Returns: true if the msr is configured to the user callstack mode.
>> + * Otherwise, false.
>> + *
>> + */
>> +bool lbr_select_user_callstack(u64 lbr_select)
>> +{
>> +	return !!(lbr_select & LBR_USER_CALLSTACK);
>> +}
>> +EXPORT_SYMBOL_GPL(lbr_select_user_callstack);
> That function is pure and tiny, wth is that an exported symbol and not
> an inline?
Thanks Peter for the comments.

Because this function uses the LBR_ macros which are defined in this 
lbr.c file.
Do you think it would be OK to move all the above LBR_ macros to 
asm/perf_event.h?

Best,
Wei