Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932986AbZJLRyc (ORCPT ); Mon, 12 Oct 2009 13:54:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932840AbZJLRyc (ORCPT ); Mon, 12 Oct 2009 13:54:32 -0400 Received: from relay2.sgi.com ([192.48.179.30]:58097 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932801AbZJLRyb (ORCPT ); Mon, 12 Oct 2009 13:54:31 -0400 Date: Mon, 12 Oct 2009 12:52:33 -0500 From: Dimitri Sivanich To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, "H. Peter Anvin" , Thomas Gleixner Subject: Re: [PATCH] x86 UV: Fixes for UV rtc timers Message-ID: <20091012175233.GA8129@sgi.com> References: <20091009134727.GB3218@sgi.com> <20091012162317.GC1272@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091012162317.GC1272@elte.hu> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6797 Lines: 248 On Mon, Oct 12, 2009 at 06:23:17PM +0200, Ingo Molnar wrote: > hm, why is the (unnecessary seeming) pushing of the > ack/exit_idle()/irq_enter()/irq_exit() sequence into the > generic_interrupt_extension() function a cleanup? It seems to make more sense to allow the users of generic_interrupt to provide their own sequence, rather than being forced into this one. > > Also, the commit log is rather terse - what is being fixed and why isnt > it separate from any cleanups? > I have added to the commit log. See below. ------------------------------------------------------------------------------- Tune/fix early timer expiry handling and return correct early timeout value for set_next_event. Modify the irq_enter/ack_APIC_irq/irq_exit sequence and move it out of smp_generic_interrupt to allow its users more flexibility. Add clocksource only boot option. Signed-off-by: Dimitri Sivanich --- arch/x86/kernel/irq.c | 10 +---- arch/x86/kernel/uv_time.c | 81 +++++++++++++++++++++++++++++------------- 2 files changed, 58 insertions(+), 33 deletions(-) Index: linux/arch/x86/kernel/uv_time.c =================================================================== --- linux.orig/arch/x86/kernel/uv_time.c 2009-10-08 11:31:05.000000000 -0500 +++ linux/arch/x86/kernel/uv_time.c 2009-10-09 07:49:05.000000000 -0500 @@ -25,6 +25,7 @@ #include #include #include +#include #include #define RTC_NAME "sgi_rtc" @@ -75,6 +76,7 @@ struct uv_rtc_timer_head { static struct uv_rtc_timer_head **blade_info __read_mostly; static int uv_rtc_enable; +static int uv_rtc_evt_enable; /* * Hardware interface routines @@ -123,7 +125,10 @@ static int uv_setup_intr(int cpu, u64 ex /* Initialize comparator value */ uv_write_global_mmr64(pnode, UVH_INT_CMPB, expires); - return (expires < uv_read_rtc(NULL) && !uv_intr_pending(pnode)); + if (uv_read_rtc(NULL) <= expires) + return 0; + + return !uv_intr_pending(pnode); } /* @@ -223,6 +228,7 @@ static int uv_rtc_set_timer(int cpu, u64 next_cpu = head->next_cpu; *t = expires; + /* Will this one be next to go off? */ if (next_cpu < 0 || bcpu == next_cpu || expires < head->cpu[next_cpu].expires) { @@ -231,7 +237,7 @@ static int uv_rtc_set_timer(int cpu, u64 *t = ULLONG_MAX; uv_rtc_find_next_timer(head, pnode); spin_unlock_irqrestore(&head->lock, flags); - return 1; + return -ETIME; } } @@ -244,7 +250,7 @@ static int uv_rtc_set_timer(int cpu, u64 * * Returns 1 if this timer was pending. */ -static int uv_rtc_unset_timer(int cpu) +static int uv_rtc_unset_timer(int cpu, int force) { int pnode = uv_cpu_to_pnode(cpu); int bid = uv_cpu_to_blade_id(cpu); @@ -256,14 +262,15 @@ static int uv_rtc_unset_timer(int cpu) spin_lock_irqsave(&head->lock, flags); - if (head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) + if ((head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) || force) rc = 1; - *t = ULLONG_MAX; - - /* Was the hardware setup for this timer? */ - if (head->next_cpu == bcpu) - uv_rtc_find_next_timer(head, pnode); + if (rc) { + *t = ULLONG_MAX; + /* Was the hardware setup for this timer? */ + if (head->next_cpu == bcpu) + uv_rtc_find_next_timer(head, pnode); + } spin_unlock_irqrestore(&head->lock, flags); @@ -310,7 +317,7 @@ static void uv_rtc_timer_setup(enum cloc break; case CLOCK_EVT_MODE_UNUSED: case CLOCK_EVT_MODE_SHUTDOWN: - uv_rtc_unset_timer(ced_cpu); + uv_rtc_unset_timer(ced_cpu, 1); break; } } @@ -320,13 +327,21 @@ static void uv_rtc_interrupt(void) struct clock_event_device *ced = &__get_cpu_var(cpu_ced); int cpu = smp_processor_id(); + exit_idle(); + + irq_enter(); + + ack_APIC_irq(); + if (!ced || !ced->event_handler) - return; + goto out; - if (uv_rtc_unset_timer(cpu) != 1) - return; + if (uv_rtc_unset_timer(cpu, 0) != 1) + goto out; ced->event_handler(ced); +out: + irq_exit(); } static int __init uv_enable_rtc(char *str) @@ -337,6 +352,14 @@ static int __init uv_enable_rtc(char *st } __setup("uvrtc", uv_enable_rtc); +static int __init uv_enable_evt_rtc(char *str) +{ + uv_rtc_evt_enable = 1; + + return 1; +} +__setup("uvrtcevt", uv_enable_evt_rtc); + static __init void uv_rtc_register_clockevents(struct work_struct *dummy) { struct clock_event_device *ced = &__get_cpu_var(cpu_ced); @@ -353,24 +376,25 @@ static __init int uv_rtc_setup_clock(voi if (!uv_rtc_enable || !is_uv_system() || generic_interrupt_extension) return -ENODEV; - generic_interrupt_extension = uv_rtc_interrupt; - clocksource_uv.mult = clocksource_hz2mult(sn_rtc_cycles_per_second, clocksource_uv.shift); rc = clocksource_register(&clocksource_uv); - if (rc) { - generic_interrupt_extension = NULL; + if (rc) + printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc); + else + printk(KERN_INFO "UV RTC clocksource registered freq %lu MHz\n", + sn_rtc_cycles_per_second/(unsigned long)1E6); + + if (rc || !uv_rtc_evt_enable) return rc; - } + + generic_interrupt_extension = uv_rtc_interrupt; /* Setup and register clockevents */ rc = uv_rtc_allocate_timers(); - if (rc) { - clocksource_unregister(&clocksource_uv); - generic_interrupt_extension = NULL; - return rc; - } + if (rc) + goto error; clock_event_device_uv.mult = div_sc(sn_rtc_cycles_per_second, NSEC_PER_SEC, clock_event_device_uv.shift); @@ -383,10 +407,17 @@ static __init int uv_rtc_setup_clock(voi rc = schedule_on_each_cpu(uv_rtc_register_clockevents); if (rc) { - clocksource_unregister(&clocksource_uv); - generic_interrupt_extension = NULL; uv_rtc_deallocate_timers(); + goto error; } + printk(KERN_INFO "UV RTC clockevents registered\n"); + + return 0; + +error: + generic_interrupt_extension = NULL; + clocksource_unregister(&clocksource_uv); + printk(KERN_INFO "UV RTC clockevents failed rc %d\n", rc); return rc; } Index: linux/arch/x86/kernel/irq.c =================================================================== --- linux.orig/arch/x86/kernel/irq.c 2009-10-08 11:31:05.000000000 -0500 +++ linux/arch/x86/kernel/irq.c 2009-10-08 11:31:15.000000000 -0500 @@ -257,18 +257,12 @@ void smp_generic_interrupt(struct pt_reg { struct pt_regs *old_regs = set_irq_regs(regs); - ack_APIC_irq(); - - exit_idle(); - - irq_enter(); - inc_irq_stat(generic_irqs); if (generic_interrupt_extension) generic_interrupt_extension(); - - irq_exit(); + else + ack_APIC_irq(); set_irq_regs(old_regs); } -- 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/