Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757333AbbGGMzL (ORCPT ); Tue, 7 Jul 2015 08:55:11 -0400 Received: from mail-wg0-f48.google.com ([74.125.82.48]:34507 "EHLO mail-wg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757266AbbGGMyr (ORCPT ); Tue, 7 Jul 2015 08:54:47 -0400 Date: Tue, 7 Jul 2015 14:54:42 +0200 From: Ingo Molnar To: Vitaly Kuznetsov Cc: x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , linux-kernel@vger.kernel.org, Radim =?utf-8?B?S3LEjW3DocWZ?= , Andrew Jones Subject: Re: [PATCH] x86/irq: hide HYP in /proc/interrupts when not on Xen/Hyper-V Message-ID: <20150707125441.GA20480@gmail.com> References: <1435922834-417-1-git-send-email-vkuznets@redhat.com> <20150704082653.GA13934@gmail.com> <87k2uc16p9.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87k2uc16p9.fsf@vitty.brq.redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2985 Lines: 80 * Vitaly Kuznetsov wrote: > Ingo Molnar writes: > > > * Vitaly Kuznetsov wrote: > > > >> Hypervisor callback interrupts are only accounted on Xen/Hyper-V and we > >> detect hypervisor's type in early boot. There is no point in having > >> always-zero HYP: line on other hypervisors or bare metal. > >> > >> Suggested-by: Radim Krčmář > >> Signed-off-by: Vitaly Kuznetsov > >> --- > >> arch/x86/kernel/irq.c | 13 +++++++++---- > >> 1 file changed, 9 insertions(+), 4 deletions(-) > >> > >> diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c > >> index 88b36648..0c82064 100644 > >> --- a/arch/x86/kernel/irq.c > >> +++ b/arch/x86/kernel/irq.c > >> @@ -18,6 +18,7 @@ > >> #include > >> #include > >> #include > >> +#include > >> > >> #define CREATE_TRACE_POINTS > >> #include > >> @@ -139,10 +140,14 @@ int arch_show_interrupts(struct seq_file *p, int prec) > >> seq_puts(p, " Machine check polls\n"); > >> #endif > >> #if IS_ENABLED(CONFIG_HYPERV) || defined(CONFIG_XEN) > >> - seq_printf(p, "%*s: ", prec, "HYP"); > >> - for_each_online_cpu(j) > >> - seq_printf(p, "%10u ", irq_stats(j)->irq_hv_callback_count); > >> - seq_puts(p, " Hypervisor callback interrupts\n"); > >> + if (x86_hyper == &x86_hyper_ms_hyperv || > >> + x86_hyper == &x86_hyper_xen) { > >> + seq_printf(p, "%*s: ", prec, "HYP"); > >> + for_each_online_cpu(j) > >> + seq_printf(p, "%10u ", > >> + irq_stats(j)->irq_hv_callback_count); > >> + seq_puts(p, " Hypervisor callback interrupts\n"); > >> + } > > > > So I think we should simplify this to: > > > > if (x86_hyper) { > > ... > > } > > > > this will print the HYP line on hypervisors that don't use > > HYPERVISOR_CALLBACK_VECTOR, but it will make it a lot more self-maintaining, we > > won't accidentally skip this line on hypervisors that start using the callback > > IRQ. > > I was under an impression KVM and Vmware don't use these hypervisor > callback irqs 'by desing' and even if one day they start using it > someone will have to put inc_irq_stat() somewhere. > > If the goal is to avoid having x86_hyper_ms_hyperv/x86_hyper_xen in > irq.c we can follow Andrew's suggestion and add a flag > (use_callback_irqs?) to struct hypervisor_x86. Yeah, a flag would be nicer, and that flag should also be used somewhere else - for example in the IRQ vector init code or so? I.e. make it only possible to use the callback vector if the flag is set properly - or something like that. That way there will never be a mismatch between flag and reality. Thanks, Ingo -- 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/