Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755552AbbGFN5m (ORCPT ); Mon, 6 Jul 2015 09:57:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46415 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756463AbbGFN5i (ORCPT ); Mon, 6 Jul 2015 09:57:38 -0400 Date: Mon, 6 Jul 2015 15:57:33 +0200 From: Andrew Jones To: Ingo Molnar Cc: Vitaly Kuznetsov , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , linux-kernel@vger.kernel.org, Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [PATCH] x86/irq: hide HYP in /proc/interrupts when not on Xen/Hyper-V Message-ID: <20150706135733.GK17217@hawk.localdomain> References: <1435922834-417-1-git-send-email-vkuznets@redhat.com> <20150704082653.GA13934@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20150704082653.GA13934@gmail.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2615 Lines: 68 On Sat, Jul 04, 2015 at 10:26:53AM +0200, Ingo Molnar wrote: > > * 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. This is a good point. When virt stuff creeps out, it's easy to lose track of it. But, I would prefer that vmware and kvm guests don't have to have a meaningless counter in /proc/interrupts. Also, for xen, I see that it only matters for x86. ARM xen builds would also have a meaningless counter. Maybe we should add a flags member to hypervisor_x86, and start using that in these types of situations. Thanks, drew -- 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/