From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1754584AbdH2Oje (ORCPT <rfc822;w@1wt.eu>);
        Tue, 29 Aug 2017 10:39:34 -0400
Received: from mail.skyhub.de ([5.9.137.197]:45370 "EHLO mail.skyhub.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1752791AbdH2Ojc (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 29 Aug 2017 10:39:32 -0400
Date: Tue, 29 Aug 2017 16:39:09 +0200
From: Borislav Petkov <bp@alien8.de>
To: Yang Zhang <yang.zhang.wz@gmail.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        wanpeng.li@hotmail.com, mst@redhat.com, pbonzini@redhat.com,
        tglx@linutronix.de, rkrcmar@redhat.com, dmatlack@google.com,
        agraf@suse.de, peterz@infradead.org, linux-doc@vger.kernel.org,
        Quan Xu <quan.xu0@gmail.com>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        Kyle Huey <me@kylehuey.com>, Andy Lutomirski <luto@kernel.org>,
        Len Brown <len.brown@intel.com>
Subject: Re: [RFC PATCH v2 3/7] sched/idle: Add poll before enter real idle
 path
Message-ID: <20170829143909.thgizi4myouyt3ch@pd.tnic>
References: <1504007201-12904-1-git-send-email-yang.zhang.wz@gmail.com>
 <1504007201-12904-4-git-send-email-yang.zhang.wz@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <1504007201-12904-4-git-send-email-yang.zhang.wz@gmail.com>
User-Agent: NeoMutt/20170113 (1.7.2)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, Aug 29, 2017 at 11:46:37AM +0000, Yang Zhang wrote:
> Add poll in do_idle. For UP VM, if there are running task, it will not
> goes into idle path, so we only enable poll in SMP VM.
> 
> Signed-off-by: Yang Zhang <yang.zhang.wz@gmail.com>
> Signed-off-by: Quan Xu <quan.xu0@gmail.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: x86@kernel.org
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Kyle Huey <me@kylehuey.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Len Brown <len.brown@intel.com>
> Cc: linux-kernel@vger.kernel.org
> ---
>  arch/x86/kernel/process.c | 7 +++++++
>  kernel/sched/idle.c       | 2 ++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> index 3ca1980..def4113 100644
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -332,6 +332,13 @@ void arch_cpu_idle(void)
>  	x86_idle();
>  }
>  
> +#if defined(CONFIG_SMP) && defined(CONFIG_PARAVIRT)
> +void arch_cpu_idle_poll(void)
> +{
> +	paravirt_idle_poll();
> +}
> +#endif

So this will get called on any system which has CONFIG_PARAVIRT enabled
*even* if they're not running any guests.

Huh?

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.