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authorLinus Torvalds <torvalds@linux-foundation.org>2015-04-14 13:36:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-14 13:36:04 -0700
commit078838d56574694d0a4815d9c1b7f28e8844638b (patch)
tree0d8c72d9dc46b0d2e72073fb928ec08e14b02b76 /arch
parenteeee78cf77df0450ca285a7cd6d73842181e825c (diff)
parent590ee7dbd569a012df705a5204fc5f1066f52b8c (diff)
downloadkernel-078838d56574694d0a4815d9c1b7f28e8844638b.tar.gz
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU changes from Ingo Molnar: "The main changes in this cycle were: - changes permitting use of call_rcu() and friends very early in boot, for example, before rcu_init() is invoked. - add in-kernel API to enable and disable expediting of normal RCU grace periods. - improve RCU's handling of (hotplug-) outgoing CPUs. - NO_HZ_FULL_SYSIDLE fixes. - tiny-RCU updates to make it more tiny. - documentation updates. - miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (58 commits) cpu: Provide smpboot_thread_init() on !CONFIG_SMP kernels as well cpu: Defer smpboot kthread unparking until CPU known to scheduler rcu: Associate quiescent-state reports with grace period rcu: Yet another fix for preemption and CPU hotplug rcu: Add diagnostics to grace-period cleanup rcutorture: Default to grace-period-initialization delays rcu: Handle outgoing CPUs on exit from idle loop cpu: Make CPU-offline idle-loop transition point more precise rcu: Eliminate ->onoff_mutex from rcu_node structure rcu: Process offlining and onlining only at grace-period start rcu: Move rcu_report_unblock_qs_rnp() to common code rcu: Rework preemptible expedited bitmask handling rcu: Remove event tracing from rcu_cpu_notify(), used by offline CPUs rcutorture: Enable slow grace-period initializations rcu: Provide diagnostic option to slow down grace-period initialization rcu: Detect stalls caused by failure to propagate up rcu_node tree rcu: Eliminate empty HOTPLUG_CPU ifdef rcu: Simplify sync_rcu_preempt_exp_init() rcu: Put all orphan-callback-related code under same comment rcu: Consolidate offline-CPU callback initialization ...
Diffstat (limited to 'arch')
-rw-r--r--arch/blackfin/mach-common/smp.c6
-rw-r--r--arch/metag/kernel/smp.c5
-rw-r--r--arch/x86/include/asm/cpu.h2
-rw-r--r--arch/x86/include/asm/smp.h2
-rw-r--r--arch/x86/kernel/smpboot.c39
-rw-r--r--arch/x86/xen/smp.c46
6 files changed, 48 insertions, 52 deletions
diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
index 8ad3e90cc8fc..1c7259597395 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -413,16 +413,14 @@ int __cpu_disable(void)
return 0;
}
-static DECLARE_COMPLETION(cpu_killed);
-
int __cpu_die(unsigned int cpu)
{
- return wait_for_completion_timeout(&cpu_killed, 5000);
+ return cpu_wait_death(cpu, 5);
}
void cpu_die(void)
{
- complete(&cpu_killed);
+ (void)cpu_report_death();
atomic_dec(&init_mm.mm_users);
atomic_dec(&init_mm.mm_count);
diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c
index f006d2276f40..ac3a199e33e7 100644
--- a/arch/metag/kernel/smp.c
+++ b/arch/metag/kernel/smp.c
@@ -261,7 +261,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
}
#ifdef CONFIG_HOTPLUG_CPU
-static DECLARE_COMPLETION(cpu_killed);
/*
* __cpu_disable runs on the processor to be shutdown.
@@ -299,7 +298,7 @@ int __cpu_disable(void)
*/
void __cpu_die(unsigned int cpu)
{
- if (!wait_for_completion_timeout(&cpu_killed, msecs_to_jiffies(1)))
+ if (!cpu_wait_death(cpu, 1))
pr_err("CPU%u: unable to kill\n", cpu);
}
@@ -314,7 +313,7 @@ void cpu_die(void)
local_irq_disable();
idle_task_exit();
- complete(&cpu_killed);
+ (void)cpu_report_death();
asm ("XOR TXENABLE, D0Re0,D0Re0\n");
}
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index d2b12988d2ed..bf2caa1dedc5 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -34,8 +34,6 @@ extern int _debug_hotplug_cpu(int cpu, int action);
#endif
#endif
-DECLARE_PER_CPU(int, cpu_state);
-
int mwait_usable(const struct cpuinfo_x86 *);
#endif /* _ASM_X86_CPU_H */
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 81d02fc7dafa..17a8dced12da 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -150,13 +150,13 @@ static inline void arch_send_call_function_ipi_mask(const struct cpumask *mask)
}
void cpu_disable_common(void);
-void cpu_die_common(unsigned int cpu);
void native_smp_prepare_boot_cpu(void);
void native_smp_prepare_cpus(unsigned int max_cpus);
void native_smp_cpus_done(unsigned int max_cpus);
void common_cpu_up(unsigned int cpunum, struct task_struct *tidle);
int native_cpu_up(unsigned int cpunum, struct task_struct *tidle);
int native_cpu_disable(void);
+int common_cpu_die(unsigned int cpu);
void native_cpu_die(unsigned int cpu);
void native_play_dead(void);
void play_dead_common(void);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 7035f6b21c3f..50e547eac8cd 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -77,9 +77,6 @@
#include <asm/realmode.h>
#include <asm/misc.h>
-/* State of each CPU */
-DEFINE_PER_CPU(int, cpu_state) = { 0 };
-
/* Number of siblings per CPU package */
int smp_num_siblings = 1;
EXPORT_SYMBOL(smp_num_siblings);
@@ -257,7 +254,7 @@ static void notrace start_secondary(void *unused)
lock_vector_lock();
set_cpu_online(smp_processor_id(), true);
unlock_vector_lock();
- per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
+ cpu_set_state_online(smp_processor_id());
x86_platform.nmi_init();
/* enable local interrupts */
@@ -954,7 +951,10 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
*/
mtrr_save_state();
- per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
+ /* x86 CPUs take themselves offline, so delayed offline is OK. */
+ err = cpu_check_up_prepare(cpu);
+ if (err && err != -EBUSY)
+ return err;
/* the FPU context is blank, nobody can own it */
__cpu_disable_lazy_restore(cpu);
@@ -1197,7 +1197,7 @@ void __init native_smp_prepare_boot_cpu(void)
switch_to_new_gdt(me);
/* already set me in cpu_online_mask in boot_cpu_init() */
cpumask_set_cpu(me, cpu_callout_mask);
- per_cpu(cpu_state, me) = CPU_ONLINE;
+ cpu_set_state_online(me);
}
void __init native_smp_cpus_done(unsigned int max_cpus)
@@ -1324,14 +1324,10 @@ static void __ref remove_cpu_from_maps(int cpu)
numa_remove_cpu(cpu);
}
-static DEFINE_PER_CPU(struct completion, die_complete);
-
void cpu_disable_common(void)
{
int cpu = smp_processor_id();
- init_completion(&per_cpu(die_complete, smp_processor_id()));
-
remove_siblinginfo(cpu);
/* It's now safe to remove this processor from the online map */
@@ -1355,24 +1351,27 @@ int native_cpu_disable(void)
return 0;
}
-void cpu_die_common(unsigned int cpu)
+int common_cpu_die(unsigned int cpu)
{
- wait_for_completion_timeout(&per_cpu(die_complete, cpu), HZ);
-}
+ int ret = 0;
-void native_cpu_die(unsigned int cpu)
-{
/* We don't do anything here: idle task is faking death itself. */
- cpu_die_common(cpu);
-
/* They ack this in play_dead() by setting CPU_DEAD */
- if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
+ if (cpu_wait_death(cpu, 5)) {
if (system_state == SYSTEM_RUNNING)
pr_info("CPU %u is now offline\n", cpu);
} else {
pr_err("CPU %u didn't die...\n", cpu);
+ ret = -1;
}
+
+ return ret;
+}
+
+void native_cpu_die(unsigned int cpu)
+{
+ common_cpu_die(cpu);
}
void play_dead_common(void)
@@ -1381,10 +1380,8 @@ void play_dead_common(void)
reset_lazy_tlbstate();
amd_e400_remove_cpu(raw_smp_processor_id());
- mb();
/* Ack it */
- __this_cpu_write(cpu_state, CPU_DEAD);
- complete(&per_cpu(die_complete, smp_processor_id()));
+ (void)cpu_report_death();
/*
* With physical CPU hotplug, we should halt the cpu
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 7413ee3706d0..86484384492e 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 */
}
/*
@@ -451,7 +447,13 @@ 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;
@@ -467,10 +469,8 @@ 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;
}
@@ -499,11 +499,11 @@ 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 */
@@ -735,6 +735,16 @@ 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
@@ -756,12 +766,6 @@ 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)
@@ -769,7 +773,7 @@ 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;