From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4517FECDE43 for ; Mon, 22 Oct 2018 01:56:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0F6B20652 for ; Mon, 22 Oct 2018 01:56:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0F6B20652 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727227AbeJVKMy (ORCPT ); Mon, 22 Oct 2018 06:12:54 -0400 Received: from mga18.intel.com ([134.134.136.126]:19932 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727182AbeJVKMx (ORCPT ); Mon, 22 Oct 2018 06:12:53 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Oct 2018 18:56:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,410,1534834800"; d="scan'208";a="83314595" Received: from yisun1-ubuntu.bj.intel.com (HELO localhost) ([10.238.156.104]) by orsmga008.jf.intel.com with ESMTP; 21 Oct 2018 18:56:25 -0700 Date: Mon, 22 Oct 2018 09:53:42 +0800 From: Yi Sun To: Juergen Gross Cc: linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de, chao.p.peng@intel.com, chao.gao@intel.com, isaku.yamahata@intel.com, michael.h.kelley@microsoft.com, tianyu.lan@microsoft.com, "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger Subject: Re: [PATCH v1 2/2] x86/hyperv: make HvNotifyLongSpinWait hypercall Message-ID: <20181022015342.GK11769@yi.y.sun> References: <1539954835-34035-1-git-send-email-yi.y.sun@linux.intel.com> <1539954835-34035-3-git-send-email-yi.y.sun@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18-10-19 16:20:52, Juergen Gross wrote: > On 19/10/2018 15:13, Yi Sun wrote: [...] > > diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h > > index 0130e48..9e88c7e 100644 > > --- a/kernel/locking/qspinlock_paravirt.h > > +++ b/kernel/locking/qspinlock_paravirt.h > > @@ -7,6 +7,8 @@ > > #include > > #include > > > > +#include > > + > > /* > > * Implement paravirt qspinlocks; the general idea is to halt the vcpus instead > > * of spinning them. > > @@ -305,6 +307,10 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev) > > wait_early = true; > > break; > > } > > +#if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) && IS_ENABLED(CONFIG_HYPERV) > > + if (!hv_notify_long_spin_wait(SPIN_THRESHOLD - loop)) > > + break; > > +#endif > > I don't like that. Why should a KVM or Xen guest call into a hyperv > specific function? > > Can't you move this to existing hyperv specific paravirt hooks? > hv_notify_long_spin_wait() must be called in this loop but it seems there is no appropriate existing paravirt hook here. So, can I add one more hook in pv_lock_ops to do this notification? > > Juergen