Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162850AbbKTObb (ORCPT ); Fri, 20 Nov 2015 09:31:31 -0500 Received: from smtp.citrix.com ([66.165.176.89]:5182 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760035AbbKTOb3 (ORCPT ); Fri, 20 Nov 2015 09:31:29 -0500 X-IronPort-AV: E=Sophos;i="5.20,323,1444694400"; d="scan'208";a="313653184" Date: Fri, 20 Nov 2015 14:31:02 +0000 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Stefano Stabellini CC: , , , , , , Ian Campbell , , , , , Christopher Covington , Ian Campbell , , Subject: Re: [PATCH v11 3/5] arm: introduce CONFIG_PARAVIRT, PARAVIRT_TIME_ACCOUNTING and pv_time_ops In-Reply-To: Message-ID: References: <1446737696-9749-3-git-send-email-stefano.stabellini@eu.citrix.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5742 Lines: 177 On Tue, 10 Nov 2015, Stefano Stabellini wrote: > On Thu, 5 Nov 2015, Stefano Stabellini wrote: > > Introduce CONFIG_PARAVIRT and PARAVIRT_TIME_ACCOUNTING on ARM. > > > > The only paravirt interface supported is pv_time_ops.steal_clock, so no > > runtime pvops patching needed. > > > > This allows us to make use of steal_account_process_tick for stolen > > ticks accounting. > > > > Signed-off-by: Stefano Stabellini > > Acked-by: Christopher Covington > > Acked-by: Ian Campbell > > CC: linux@arm.linux.org.uk > > CC: will.deacon@arm.com > > CC: nico@linaro.org > > CC: marc.zyngier@arm.com > > CC: cov@codeaurora.org > > CC: arnd@arndb.de > > CC: olof@lixom.net > > > Russell, > are you OK with this patch? Russell, I am going to drop this patch and add a small #ifdef to arch/arm/xen/enlighten.c to be able to use this functionality on arm64. If you change your mind let me know. > > > > > > Changes in v10: > > - replace "---help---" with "help" > > > > Changes in v7: > > - ifdef CONFIG_PARAVIRT the content of paravirt.h. > > > > Changes in v3: > > - improve commit description and Kconfig help text; > > - no need to initialize pv_time_ops; > > - add PARAVIRT_TIME_ACCOUNTING. > > --- > > arch/arm/Kconfig | 20 ++++++++++++++++++++ > > arch/arm/include/asm/paravirt.h | 20 ++++++++++++++++++++ > > arch/arm/kernel/Makefile | 1 + > > arch/arm/kernel/paravirt.c | 25 +++++++++++++++++++++++++ > > 4 files changed, 66 insertions(+) > > create mode 100644 arch/arm/include/asm/paravirt.h > > create mode 100644 arch/arm/kernel/paravirt.c > > > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > > index f1ed110..60be104 100644 > > --- a/arch/arm/Kconfig > > +++ b/arch/arm/Kconfig > > @@ -1823,6 +1823,25 @@ config SWIOTLB > > config IOMMU_HELPER > > def_bool SWIOTLB > > > > +config PARAVIRT > > + bool "Enable paravirtualization code" > > + help > > + This changes the kernel so it can modify itself when it is run > > + under a hypervisor, potentially improving performance significantly > > + over full virtualization. > > + > > +config PARAVIRT_TIME_ACCOUNTING > > + bool "Paravirtual steal time accounting" > > + select PARAVIRT > > + default n > > + help > > + Select this option to enable fine granularity task steal time > > + accounting. Time spent executing other tasks in parallel with > > + the current vCPU is discounted from the vCPU power. To account for > > + that, there can be a small performance impact. > > + > > + If in doubt, say N here. > > + > > config XEN_DOM0 > > def_bool y > > depends on XEN > > @@ -1836,6 +1855,7 @@ config XEN > > select ARCH_DMA_ADDR_T_64BIT > > select ARM_PSCI > > select SWIOTLB_XEN > > + select PARAVIRT > > help > > Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. > > > > diff --git a/arch/arm/include/asm/paravirt.h b/arch/arm/include/asm/paravirt.h > > new file mode 100644 > > index 0000000..8435ff59 > > --- /dev/null > > +++ b/arch/arm/include/asm/paravirt.h > > @@ -0,0 +1,20 @@ > > +#ifndef _ASM_ARM_PARAVIRT_H > > +#define _ASM_ARM_PARAVIRT_H > > + > > +#ifdef CONFIG_PARAVIRT > > +struct static_key; > > +extern struct static_key paravirt_steal_enabled; > > +extern struct static_key paravirt_steal_rq_enabled; > > + > > +struct pv_time_ops { > > + unsigned long long (*steal_clock)(int cpu); > > +}; > > +extern struct pv_time_ops pv_time_ops; > > + > > +static inline u64 paravirt_steal_clock(int cpu) > > +{ > > + return pv_time_ops.steal_clock(cpu); > > +} > > +#endif > > + > > +#endif > > diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile > > index af9e59b..3e6e937 100644 > > --- a/arch/arm/kernel/Makefile > > +++ b/arch/arm/kernel/Makefile > > @@ -81,6 +81,7 @@ obj-$(CONFIG_VDSO) += vdso.o > > ifneq ($(CONFIG_ARCH_EBSA110),y) > > obj-y += io.o > > endif > > +obj-$(CONFIG_PARAVIRT) += paravirt.o > > > > head-y := head$(MMUEXT).o > > obj-$(CONFIG_DEBUG_LL) += debug.o > > diff --git a/arch/arm/kernel/paravirt.c b/arch/arm/kernel/paravirt.c > > new file mode 100644 > > index 0000000..53f371e > > --- /dev/null > > +++ b/arch/arm/kernel/paravirt.c > > @@ -0,0 +1,25 @@ > > +/* > > + * This program is free software; you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License version 2 as > > + * published by the Free Software Foundation. > > + * > > + * This program is distributed in the hope that it will be useful, > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > + * GNU General Public License for more details. > > + * > > + * Copyright (C) 2013 Citrix Systems > > + * > > + * Author: Stefano Stabellini > > + */ > > + > > +#include > > +#include > > +#include > > +#include > > + > > +struct static_key paravirt_steal_enabled; > > +struct static_key paravirt_steal_rq_enabled; > > + > > +struct pv_time_ops pv_time_ops; > > +EXPORT_SYMBOL_GPL(pv_time_ops); > > -- > > 1.7.10.4 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/