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Subject[tip:x86/urgent] x86/core, x86/xen/smp: Use 'die_complete' completion when taking CPU down
Commit-ID:  54279552bd260532d90e7a59fbc931924bbb0f7b
Gitweb: http://git.kernel.org/tip/54279552bd260532d90e7a59fbc931924bbb0f7b
Author: Boris Ostrovsky <boris.ostrovsky@oracle.com>
AuthorDate: Fri, 31 Oct 2014 11:49:32 -0400
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 10 Nov 2014 11:16:40 +0100

x86/core, x86/xen/smp: Use 'die_complete' completion when taking CPU down

Commit 2ed53c0d6cc9 ("x86/smpboot: Speed up suspend/resume by
avoiding 100ms sleep for CPU offline during S3") introduced
completions to CPU offlining process. These completions are not
initialized on Xen kernels causing a panic in
play_dead_common().

Move handling of die_complete into common routines to make them
available to Xen guests.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: tianyu.lan@intel.com
Cc: konrad.wilk@oracle.com
Cc: xen-devel@lists.xenproject.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1414770572-7950-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/smp.h | 1 +
arch/x86/kernel/smpboot.c | 15 +++++++++++----
arch/x86/xen/smp.c | 3 +++
3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 8cd27e0..8cd1cc3 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -150,6 +150,7 @@ 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);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 4d2128a..668d8f2 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1303,10 +1303,14 @@ 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 */
@@ -1316,8 +1320,6 @@ void cpu_disable_common(void)
fixup_irqs();
}

-static DEFINE_PER_CPU(struct completion, die_complete);
-
int native_cpu_disable(void)
{
int ret;
@@ -1327,16 +1329,21 @@ int native_cpu_disable(void)
return ret;

clear_local_APIC();
- init_completion(&per_cpu(die_complete, smp_processor_id()));
cpu_disable_common();

return 0;
}

+void cpu_die_common(unsigned int cpu)
+{
+ wait_for_completion_timeout(&per_cpu(die_complete, cpu), HZ);
+}
+
void native_cpu_die(unsigned int cpu)
{
/* We don't do anything here: idle task is faking death itself. */
- wait_for_completion_timeout(&per_cpu(die_complete, cpu), HZ);
+
+ cpu_die_common(cpu);

/* They ack this in play_dead() by setting CPU_DEAD */
if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 8650cdb..4c071ae 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -510,6 +510,9 @@ static void xen_cpu_die(unsigned int cpu)
current->state = TASK_UNINTERRUPTIBLE;
schedule_timeout(HZ/10);
}
+
+ cpu_die_common(cpu);
+
xen_smp_intr_free(cpu);
xen_uninit_lock_cpu(cpu);
xen_teardown_timer(cpu);

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