From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760053Ab0JZQiD (ORCPT ); Tue, 26 Oct 2010 12:38:03 -0400 Received: from claw.goop.org ([74.207.240.146]:44256 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760044Ab0JZQiA (ORCPT ); Tue, 26 Oct 2010 12:38:00 -0400 Message-ID: <4CC703E5.6000009@goop.org> Date: Tue, 26 Oct 2010 09:37:57 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc13 Lightning/1.0b3pre Thunderbird/3.1.4 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk CC: Ian Campbell , Stefano Stabellini , "H. Peter Anvin" , linux-kernel@vger.kernel.org, mingo@elte.hu, xen-devel@lists.xensource.com, tglx@linutronix.de Subject: Re: [PATCH 4/5] xen: events: dynamically allocate irq info structures References: <1288023736.11153.40.camel@zakaz.uk.xensource.com> <1288023813-31989-4-git-send-email-ian.campbell@citrix.com> <20101026143027.GB9557@dumpdata.com> In-Reply-To: <20101026143027.GB9557@dumpdata.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/26/2010 07:30 AM, Konrad Rzeszutek Wilk wrote: > On Mon, Oct 25, 2010 at 05:23:32PM +0100, Ian Campbell wrote: >> Removes nr_irq sized array allocation at start of day. >> >> Signed-off-by: Ian Campbell >> --- >> drivers/xen/events.c | 50 +++++++++++++++++++++++++++++++++++++++++--------- >> 1 files changed, 41 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/xen/events.c b/drivers/xen/events.c >> index 94055ea..9b58505 100644 >> --- a/drivers/xen/events.c >> +++ b/drivers/xen/events.c >> @@ -56,6 +56,8 @@ >> */ >> static DEFINE_SPINLOCK(irq_mapping_update_lock); >> >> +static LIST_HEAD(xen_irq_list_head); >> + >> /* IRQ <-> VIRQ mapping. */ >> static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1}; >> >> @@ -85,6 +87,7 @@ enum xen_irq_type { >> */ >> struct irq_info >> { >> + struct list_head list; >> enum xen_irq_type type; /* type */ >> unsigned short evtchn; /* event channel */ >> unsigned short cpu; /* cpu bound */ >> @@ -103,7 +106,6 @@ struct irq_info >> #define PIRQ_NEEDS_EOI (1 << 0) >> #define PIRQ_SHAREABLE (1 << 1) >> >> -static struct irq_info *irq_info; >> static int *pirq_to_irq; >> static int nr_pirqs; >> >> @@ -132,7 +134,7 @@ static struct irq_chip xen_pirq_chip; >> /* Get info for IRQ */ >> static struct irq_info *info_for_irq(unsigned irq) >> { >> - return &irq_info[irq]; >> + return get_irq_data(irq); >> } >> >> /* Constructors for packed IRQ information. */ >> @@ -315,7 +317,7 @@ static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu) >> __clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq))); >> __set_bit(chn, cpu_evtchn_mask(cpu)); >> >> - irq_info[irq].cpu = cpu; >> + info_for_irq(irq)->cpu = cpu; >> } >> >> static void init_evtchn_cpu_bindings(void) >> @@ -428,6 +430,21 @@ static int find_unbound_pirq(void) >> return -1; >> } >> >> +static void xen_irq_init(unsigned irq) >> +{ >> + struct irq_info *info; >> + >> + info = kmalloc(sizeof(*info), GFP_KERNEL); >> + if (info == NULL) >> + panic("Unable to allocate metadata for IRQ%d\n", irq); > There is a bunch of panic around allocating IRQs. There is one earlier > in xen_irq_alloc too, and I was wondering - would it make sense to > perhaps print an error to both the hypervisor and the kernel and > just return -1 as an IRQ and let the kernel continue with its normal > failure path? > > I am thinking just in terms of making the system still be able to > work even if parts of it are busted, instead of just crashing the system. > > Not sure which philosophy is domiant in the Linux kernel? Normally to print something and struggle on, rather than crash over every little thing. There's been a general tendency to convert BUG into WARN, for example. J