From 9d133e5db993d577bd868b54083869fe5479fcff Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Fri, 29 Jan 2010 11:42:21 -0800 Subject: x86, irq: Move __setup_vector_irq() before the first irq enable in cpu online path Lowest priority delivery of logical flat mode is broken on some systems, such that even when IO-APIC RTE says deliver the interrupt to a particular CPU, interrupt subsystem delivers the interrupt to totally different CPU. For example, this behavior was observed on a P4 based system with SiS chipset which was reported by Li Zefan. We have been handling this kind of behavior by making sure that in logical flat mode, we assign the same vector to irq mappings on all the 8 possible logical cpu's. But we have been doing this initial assignment (__setup_vector_irq()) a little late (before which interrupts were already enabled for a short duration). Move the __setup_vector_irq() before the first irq enable point in the cpu online path to avoid the issue of not handling some interrupts that wrongly hit the cpu which is still coming online. Signed-off-by: Suresh Siddha LKML-Reference: <20100129194330.283696385@sbs-t61.sc.intel.com> Tested-by: Li Zefan Cc: Yinghai Lu Cc: Eric W. Biederman Signed-off-by: H. Peter Anvin --- arch/x86/kernel/smpboot.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/smpboot.c') diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 678d0b8c26f3..b2ebcba729d9 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -241,6 +241,11 @@ static void __cpuinit smp_callin(void) map_cpu_to_logical_apicid(); notify_cpu_starting(cpuid); + + /* + * Need to setup vector mappings before we enable interrupts. + */ + __setup_vector_irq(smp_processor_id()); /* * Get our bogomips. * @@ -315,7 +320,6 @@ notrace static void __cpuinit start_secondary(void *unused) */ ipi_call_lock(); lock_vector_lock(); - __setup_vector_irq(smp_processor_id()); set_cpu_online(smp_processor_id(), true); unlock_vector_lock(); ipi_call_unlock(); -- cgit From 2b633e3fac5efada088b57d31e65401f22bcc18f Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Wed, 10 Feb 2010 01:20:37 -0800 Subject: smp: Use nr_cpus= to set nr_cpu_ids early On x86, before prefill_possible_map(), nr_cpu_ids will be NR_CPUS aka CONFIG_NR_CPUS. Add nr_cpus= to set nr_cpu_ids. so we can simulate cpus <=8 are installed on normal config. -v2: accordging to Christoph, acpi_numa_init should use nr_cpu_ids in stead of NR_CPUS. -v3: add doc in kernel-parameters.txt according to Andrew. Signed-off-by: Yinghai Lu LKML-Reference: <1265793639-15071-34-git-send-email-yinghai@kernel.org> Acked-by: Linus Torvalds Signed-off-by: H. Peter Anvin Cc: Tony Luck --- arch/x86/kernel/smpboot.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'arch/x86/kernel/smpboot.c') diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 678d0b8c26f3..eff2fe175422 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1213,11 +1213,12 @@ __init void prefill_possible_map(void) total_cpus = max_t(int, possible, num_processors + disabled_cpus); - if (possible > CONFIG_NR_CPUS) { + /* nr_cpu_ids could be reduced via nr_cpus= */ + if (possible > nr_cpu_ids) { printk(KERN_WARNING "%d Processors exceeds NR_CPUS limit of %d\n", - possible, CONFIG_NR_CPUS); - possible = CONFIG_NR_CPUS; + possible, nr_cpu_ids); + possible = nr_cpu_ids; } printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n", -- cgit