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authorIngo Molnar <mingo@kernel.org>2015-03-27 10:04:06 +0100
committerIngo Molnar <mingo@kernel.org>2015-03-27 10:04:06 +0100
commit4bfe186dbe0a058680e4bfb0d673194f0ceaffd4 (patch)
tree5e374857dcd979d50f51c7091505784cb053d078 /arch/x86/xen
parent3c435c1e472ba344ee25f795f4807d4457e61f6c (diff)
parent42528795ac1c8d7ba021797ec004904168956d64 (diff)
Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney: - Documentation updates. - Changes permitting use of call_rcu() and friends very early in boot, for example, before rcu_init() is invoked. - Miscellaneous fixes. - Add in-kernel API to enable and disable expediting of normal RCU grace periods. - Improve RCU's handling of (hotplug-) outgoing CPUs. Note: ARM support is lagging a bit here, and these improved diagnostics might generate (harmless) splats. - NO_HZ_FULL_SYSIDLE fixes. - Tiny RCU updates to make it more tiny. Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/smp.c46
1 files changed, 25 insertions, 21 deletions
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 08e8489c47f1..1c5e760f34ca 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -90,14 +90,10 @@ static void cpu_bringup(void)
set_cpu_online(cpu, true);
- this_cpu_write(cpu_state, CPU_ONLINE);
-
- wmb();
+ cpu_set_state_online(cpu); /* Implies full memory barrier. */
/* We can take interrupts now: we're officially "up". */
local_irq_enable();
-
- wmb(); /* make sure everything is out */
}
/*
@@ -459,7 +455,13 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
xen_setup_timer(cpu);
xen_init_lock_cpu(cpu);
- per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
+ /*
+ * PV VCPUs are always successfully taken down (see 'while' loop
+ * in xen_cpu_die()), so -EBUSY is an error.
+ */
+ rc = cpu_check_up_prepare(cpu);
+ if (rc)
+ return rc;
/* make sure interrupts start blocked */
per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
@@ -479,10 +481,8 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
BUG_ON(rc);
- while(per_cpu(cpu_state, cpu) != CPU_ONLINE) {
+ while (cpu_report_state(cpu) != CPU_ONLINE)
HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
- barrier();
- }
return 0;
}
@@ -511,11 +511,11 @@ static void xen_cpu_die(unsigned int cpu)
schedule_timeout(HZ/10);
}
- cpu_die_common(cpu);
-
- xen_smp_intr_free(cpu);
- xen_uninit_lock_cpu(cpu);
- xen_teardown_timer(cpu);
+ if (common_cpu_die(cpu) == 0) {
+ xen_smp_intr_free(cpu);
+ xen_uninit_lock_cpu(cpu);
+ xen_teardown_timer(cpu);
+ }
}
static void xen_play_dead(void) /* used only with HOTPLUG_CPU */
@@ -747,6 +747,16 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
static int xen_hvm_cpu_up(unsigned int cpu, struct task_struct *tidle)
{
int rc;
+
+ /*
+ * This can happen if CPU was offlined earlier and
+ * offlining timed out in common_cpu_die().
+ */
+ if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
+ xen_smp_intr_free(cpu);
+ xen_uninit_lock_cpu(cpu);
+ }
+
/*
* xen_smp_intr_init() needs to run before native_cpu_up()
* so that IPI vectors are set up on the booting CPU before
@@ -768,12 +778,6 @@ static int xen_hvm_cpu_up(unsigned int cpu, struct task_struct *tidle)
return rc;
}
-static void xen_hvm_cpu_die(unsigned int cpu)
-{
- xen_cpu_die(cpu);
- native_cpu_die(cpu);
-}
-
void __init xen_hvm_smp_init(void)
{
if (!xen_have_vector_callback)
@@ -781,7 +785,7 @@ void __init xen_hvm_smp_init(void)
smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus;
smp_ops.smp_send_reschedule = xen_smp_send_reschedule;
smp_ops.cpu_up = xen_hvm_cpu_up;
- smp_ops.cpu_die = xen_hvm_cpu_die;
+ smp_ops.cpu_die = xen_cpu_die;
smp_ops.send_call_func_ipi = xen_smp_send_call_function_ipi;
smp_ops.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi;
smp_ops.smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu;