From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752668Ab3FFS6N (ORCPT ); Thu, 6 Jun 2013 14:58:13 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:47314 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751264Ab3FFS6M (ORCPT ); Thu, 6 Jun 2013 14:58:12 -0400 Date: Thu, 6 Jun 2013 14:58:00 -0400 From: Konrad Rzeszutek Wilk To: Jan Beulich Cc: xen-devel , linux-kernel@vger.kernel.org Subject: Re: [Xen-devel] [PATCH 2/9] xen/smp: Introduce a common structure to contain the IRQ name and interrupt line. Message-ID: <20130606185800.GB21538@konrad-lan.dumpdata.com> References: <1370447678-22367-1-git-send-email-konrad.wilk@oracle.com> <1370447678-22367-3-git-send-email-konrad.wilk@oracle.com> <51B0537702000078000DBC74@nat28.tlf.novell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51B0537702000078000DBC74@nat28.tlf.novell.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 06, 2013 at 08:16:39AM +0100, Jan Beulich wrote: > >>> On 05.06.13 at 17:54, Konrad Rzeszutek Wilk wrote: > > This patch adds a new structure to contain the common two things > > that each of the per-cpu interrupts need: > > - an interrupt number, > > - and the name of the interrupt (to be added in 'xen/smp: Don't leak > > interrupt name when offlining'). > > > > This allows us to carry the tuple of the per-cpu interrupt data structure > > and expand it as we need in the future. > > > > Signed-off-by: Konrad Rzeszutek Wilk > > --- > > arch/x86/xen/smp.c | 44 ++++++++++++++++++++++++-------------------- > > 1 file changed, 24 insertions(+), 20 deletions(-) > > > > diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c > > index 19fc9f3..f5b29ec 100644 > > --- a/arch/x86/xen/smp.c > > +++ b/arch/x86/xen/smp.c > > @@ -39,11 +39,15 @@ > > > > cpumask_var_t xen_cpu_initialized_map; > > > > -static DEFINE_PER_CPU(int, xen_resched_irq); > > -static DEFINE_PER_CPU(int, xen_callfunc_irq); > > -static DEFINE_PER_CPU(int, xen_callfuncsingle_irq); > > -static DEFINE_PER_CPU(int, xen_irq_work); > > -static DEFINE_PER_CPU(int, xen_debug_irq) = -1; > > +struct xen_common_irq { > > + int irq; > > + char *name; > > +}; > > +static DEFINE_PER_CPU(struct xen_common_irq, xen_resched_irq); > > +static DEFINE_PER_CPU(struct xen_common_irq, xen_callfunc_irq); > > +static DEFINE_PER_CPU(struct xen_common_irq, xen_callfuncsingle_irq); > > +static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work); > > +static DEFINE_PER_CPU(struct xen_common_irq, xen_debug_irq) = { .irq = -1 }; > > I have to admit that I'm quite puzzled by this still being massaged > the way it is, rather than getting converted to proper per-CPU > IRQs (i.e. with one global IRQ and only per-CPU event channels). > Not only conserves this on resources (irrespective of IRQs not > being a scarce resources anymore with SPARSE_IRQS), it also > makes /proc/interrupts output a lot more manageable on domains > with many vCPU-s. > > I did this years ago for our kernels, but due to time constraints > can't offer to do the same for the upstream kernel until we get > ready to switch to using it in favor of the forward port. I believe it was just the matter of other higher priority items preempting it. Let me put it on the "v3.11 and the future list" so that I won't forget. Thanks!