Messages in this thread Patch in this message | | | Date | Sun, 22 Aug 2004 10:47:25 -0400 (EDT) | From | Zwane Mwaikambo <> | Subject | Re: [PATCH][2.6] Hotplug cpu: Fix APIC queued timer vector race |
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On Sun, 22 Aug 2004, Rusty Russell wrote:
> On Sun, 2004-08-22 at 00:10, Zwane Mwaikambo wrote: > > Some timer interrupt vectors were queued on the Local APIC and were being > > serviced when we enabled interrupts again in fixup_irqs(), so we need to > > mask the APIC timer, enable interrupts so that any queued interrupts get > > processed whilst the processor is still on the online map and then clear > > ourselves from the online map. 1ms is a nice safe number even under heavy > > interrupt load with higher priority vectors queued. Andrew this is > > the patch i promised, Rusty, i'm not sure if you find > > __attribute__((weak)) offensive... > > It's horrible. Please move the unsetting of the cpu_online bit into the > arch-specific __cpu_disable() code for each arch, which is consistent > and also simplifies things.
Alright this should do it then;
Thanks
Signed-off-by: Zwane Mwaikambo <zwane@linuxpower.ca>
arch/i386/kernel/smpboot.c | 10 ++++++++-- arch/ia64/kernel/smpboot.c | 1 + arch/ppc64/kernel/smp.c | 4 +++- arch/s390/kernel/smp.c | 4 +++- kernel/cpu.c | 3 --- 5 files changed, 15 insertions(+), 7 deletions(-)
Index: linux-2.6.8.1-mm2/kernel/cpu.c =================================================================== RCS file: /home/cvsroot/linux-2.6.8.1-mm2/kernel/cpu.c,v retrieving revision 1.1.1.1 diff -u -p -B -r1.1.1.1 cpu.c --- linux-2.6.8.1-mm2/kernel/cpu.c 19 Aug 2004 20:52:08 -0000 1.1.1.1 +++ linux-2.6.8.1-mm2/kernel/cpu.c 22 Aug 2004 14:28:17 -0000 @@ -89,9 +89,6 @@ static int take_cpu_down(void *unused) { int err;
- /* Take offline: makes arch_cpu_down somewhat easier. */ - cpu_clear(smp_processor_id(), cpu_online_map); - /* Ensure this CPU doesn't handle any more interrupts. */ err = __cpu_disable(); if (err < 0) Index: linux-2.6.8.1-mm2/arch/i386/kernel/smpboot.c =================================================================== RCS file: /home/cvsroot/linux-2.6.8.1-mm2/arch/i386/kernel/smpboot.c,v retrieving revision 1.1.1.1 diff -u -p -B -r1.1.1.1 smpboot.c --- linux-2.6.8.1-mm2/arch/i386/kernel/smpboot.c 19 Aug 2004 20:51:36 -0000 1.1.1.1 +++ linux-2.6.8.1-mm2/arch/i386/kernel/smpboot.c 22 Aug 2004 14:30:04 -0000 @@ -1172,10 +1172,16 @@ int __cpu_disable(void) if (smp_processor_id() == 0) return -EBUSY;
- fixup_irqs(); - /* We enable the timer again on the exit path of the death loop */ disable_APIC_timer(); + /* Allow any queued timer interrupts to get serviced */ + local_irq_enable(); + mdelay(1); + local_irq_disable(); + + /* It's now safe to remove this processor from the online map */ + cpu_clear(smp_processor_id(), cpu_online_map); + fixup_irqs(); return 0; }
Index: linux-2.6.8.1-mm2/arch/ia64/kernel/smpboot.c =================================================================== RCS file: /home/cvsroot/linux-2.6.8.1-mm2/arch/ia64/kernel/smpboot.c,v retrieving revision 1.1.1.1 diff -u -p -B -r1.1.1.1 smpboot.c --- linux-2.6.8.1-mm2/arch/ia64/kernel/smpboot.c 19 Aug 2004 20:51:37 -0000 1.1.1.1 +++ linux-2.6.8.1-mm2/arch/ia64/kernel/smpboot.c 22 Aug 2004 14:32:22 -0000 @@ -591,6 +591,7 @@ int __cpu_disable(void) if (cpu == 0) return -EBUSY;
+ cpu_clear(cpu, cpu_online_map); fixup_irqs(); local_flush_tlb_all(); printk ("Disabled cpu %u\n", smp_processor_id()); Index: linux-2.6.8.1-mm2/arch/ppc64/kernel/smp.c =================================================================== RCS file: /home/cvsroot/linux-2.6.8.1-mm2/arch/ppc64/kernel/smp.c,v retrieving revision 1.1.1.1 diff -u -p -B -r1.1.1.1 smp.c --- linux-2.6.8.1-mm2/arch/ppc64/kernel/smp.c 19 Aug 2004 20:51:50 -0000 1.1.1.1 +++ linux-2.6.8.1-mm2/arch/ppc64/kernel/smp.c 22 Aug 2004 14:39:31 -0000 @@ -254,11 +254,13 @@ int __cpu_disable(void) { /* FIXME: go put this in a header somewhere */ extern void xics_migrate_irqs_away(void); + int cpu = smp_processor_id();
+ cpu_clear(cpu, cpu_online_map); systemcfg->processorCount--;
/*fix boot_cpuid here*/ - if (smp_processor_id() == boot_cpuid) + if (cpu == boot_cpuid) boot_cpuid = any_online_cpu(cpu_online_map);
/* FIXME: abstract this to not be platform specific later on */ Index: linux-2.6.8.1-mm2/arch/s390/kernel/smp.c =================================================================== RCS file: /home/cvsroot/linux-2.6.8.1-mm2/arch/s390/kernel/smp.c,v retrieving revision 1.1.1.1 diff -u -p -B -r1.1.1.1 smp.c --- linux-2.6.8.1-mm2/arch/s390/kernel/smp.c 19 Aug 2004 20:51:50 -0000 1.1.1.1 +++ linux-2.6.8.1-mm2/arch/s390/kernel/smp.c 22 Aug 2004 14:39:13 -0000 @@ -682,9 +682,11 @@ __cpu_disable(void) { unsigned long flags; ec_creg_mask_parms cr_parms; + int cpu = smp_processor_id();
+ cpu_clear(cpu, cpu_online_map); spin_lock_irqsave(&smp_reserve_lock, flags); - if (smp_cpu_reserved[smp_processor_id()] != 0) { + if (smp_cpu_reserved[cpu] != 0) { spin_unlock_irqrestore(&smp_reserve_lock, flags); return -EBUSY; } - 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/
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