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149 lines
4.5 KiB
149 lines
4.5 KiB
From: jbeulich@novell.com
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Subject: eliminate REBOOT_VECTOR
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Patch-mainline: n/a
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We can do without it, and can that way save one event channel per CPU
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(i.e. a significant number when having many CPUs, given that there are
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only 1024/4096 of them on 32-/64-bit).
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--- head-2010-04-15.orig/arch/x86/include/asm/hw_irq.h 2010-03-24 16:00:05.000000000 +0100
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+++ head-2010-04-15/arch/x86/include/asm/hw_irq.h 2010-03-30 17:14:57.000000000 +0200
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@@ -137,7 +137,6 @@ extern asmlinkage void smp_invalidate_in
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extern irqreturn_t smp_reschedule_interrupt(int, void *);
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extern irqreturn_t smp_call_function_interrupt(int, void *);
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extern irqreturn_t smp_call_function_single_interrupt(int, void *);
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-extern irqreturn_t smp_reboot_interrupt(int, void *);
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#endif
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#endif
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--- head-2010-04-15.orig/arch/x86/include/mach-xen/asm/irq_vectors.h 2010-03-29 18:11:31.000000000 +0200
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+++ head-2010-04-15/arch/x86/include/mach-xen/asm/irq_vectors.h 2010-03-30 17:15:14.000000000 +0200
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@@ -12,8 +12,7 @@
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#define CALL_FUNCTION_VECTOR 1
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#define CALL_FUNC_SINGLE_VECTOR 2
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#define SPIN_UNLOCK_VECTOR 3
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-#define REBOOT_VECTOR 4
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-#define NR_IPIS 5
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+#define NR_IPIS 4
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/*
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* The maximum number of vectors supported by i386 processors
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--- head-2010-04-15.orig/arch/x86/kernel/smp-xen.c 2010-04-15 10:48:32.000000000 +0200
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+++ head-2010-04-15/arch/x86/kernel/smp-xen.c 2010-04-15 11:43:22.000000000 +0200
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@@ -29,6 +29,9 @@
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#include <asm/proto.h>
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#include <asm/ipi.h>
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#include <xen/evtchn.h>
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+
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+static unsigned int __read_mostly reboot = NR_CPUS;
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+
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/*
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* Some notes on x86 processor bugs affecting SMP operation:
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*
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@@ -132,19 +135,6 @@ void xen_send_call_func_ipi(const struct
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xen_send_IPI_mask_allbutself(mask, CALL_FUNCTION_VECTOR);
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}
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-/*
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- * this function calls the 'stop' function on all other CPUs in the system.
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- */
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-
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-irqreturn_t smp_reboot_interrupt(int irq, void *dev_id)
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-{
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- irq_enter();
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- stop_this_cpu(NULL);
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- irq_exit();
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-
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- return IRQ_HANDLED;
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-}
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-
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void xen_smp_send_stop(void)
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{
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unsigned long flags;
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@@ -159,8 +149,10 @@ void xen_smp_send_stop(void)
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* (this implies we cannot stop CPUs spinning with irq off
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* currently)
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*/
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+ reboot = raw_smp_processor_id();
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+ wmb();
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if (num_online_cpus() > 1) {
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- xen_send_IPI_allbutself(REBOOT_VECTOR);
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+ xen_send_IPI_allbutself(RESCHEDULE_VECTOR);
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/* Don't wait longer than a second */
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wait = USEC_PER_SEC;
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@@ -180,7 +172,13 @@ void xen_smp_send_stop(void)
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*/
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irqreturn_t smp_reschedule_interrupt(int irq, void *dev_id)
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{
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- inc_irq_stat(irq_resched_count);
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+ if (likely(reboot >= NR_CPUS) || reboot == raw_smp_processor_id())
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+ inc_irq_stat(irq_resched_count);
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+ else {
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+ irq_enter();
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+ stop_this_cpu(NULL);
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+ irq_exit();
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+ }
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return IRQ_HANDLED;
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}
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--- head-2010-04-15.orig/drivers/xen/core/smpboot.c 2010-03-25 14:39:15.000000000 +0100
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+++ head-2010-04-15/drivers/xen/core/smpboot.c 2010-04-15 11:43:29.000000000 +0200
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@@ -44,7 +44,6 @@ EXPORT_PER_CPU_SYMBOL(cpu_info);
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static int __read_mostly resched_irq = -1;
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static int __read_mostly callfunc_irq = -1;
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static int __read_mostly call1func_irq = -1;
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-static int __read_mostly reboot_irq = -1;
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#ifdef CONFIG_X86_LOCAL_APIC
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#define set_cpu_to_apicid(cpu, apicid) (per_cpu(x86_cpu_to_apicid, cpu) = (apicid))
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@@ -118,10 +117,6 @@ static int __cpuinit xen_smp_intr_init(u
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.handler = smp_call_function_single_interrupt,
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.flags = IRQF_DISABLED,
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.name = "call1func"
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- }, reboot_action = {
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- .handler = smp_reboot_interrupt,
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- .flags = IRQF_DISABLED,
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- .name = "reboot"
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};
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int rc;
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@@ -155,19 +150,9 @@ static int __cpuinit xen_smp_intr_init(u
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else
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BUG_ON(call1func_irq != rc);
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- rc = bind_ipi_to_irqaction(REBOOT_VECTOR,
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- cpu,
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- &reboot_action);
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- if (rc < 0)
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- goto unbind_call1;
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- if (reboot_irq < 0)
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- reboot_irq = rc;
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- else
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- BUG_ON(reboot_irq != rc);
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-
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rc = xen_spinlock_init(cpu);
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if (rc < 0)
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- goto unbind_reboot;
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+ goto unbind_call1;
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if ((cpu != 0) && ((rc = local_setup_timer(cpu)) != 0))
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goto fail;
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@@ -176,8 +161,6 @@ static int __cpuinit xen_smp_intr_init(u
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fail:
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xen_spinlock_cleanup(cpu);
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- unbind_reboot:
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- unbind_from_per_cpu_irq(reboot_irq, cpu, NULL);
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unbind_call1:
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unbind_from_per_cpu_irq(call1func_irq, cpu, NULL);
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unbind_call:
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@@ -196,7 +179,6 @@ static void __cpuinit xen_smp_intr_exit(
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unbind_from_per_cpu_irq(resched_irq, cpu, NULL);
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unbind_from_per_cpu_irq(callfunc_irq, cpu, NULL);
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unbind_from_per_cpu_irq(call1func_irq, cpu, NULL);
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- unbind_from_per_cpu_irq(reboot_irq, cpu, NULL);
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xen_spinlock_cleanup(cpu);
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}
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#endif
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