[PATCH v2 0/2] Reinstate irq alloc/dealloc locking patch

[PATCH v2 0/2] Reinstate irq alloc/dealloc locking patch

[Boris Ostrovsky]

Original version of that patch (commit a89941816726) had to be reverted
due to Xen allocating irqs in its cpu_up ops.

The first patch moves allocations into hotplug notifiers and the second
one restores the original patch (with minor adjustments to new hotplug
framework)

This originally went through tip tree but after a couple of failures
reportedby kbuild robot (due to various combinations of CONFIG_SMP and
CONFIG_XEN_PVH) I decided to take it through Xen tree (with config problems
hopefully finally fixed).

Boris Ostrovsky (2):
  xen/x86: Move irq allocation from Xen smp_op.cpu_up()
  hotplug: Prevent alloc/free of irq descriptors during cpu up/down
    (again)

 arch/x86/kernel/smpboot.c | 11 ---------
 arch/x86/xen/enlighten.c  | 61 +++++++++++++++++++++++++++++++++++++----------
 arch/x86/xen/smp.c        | 45 ++--------------------------------
 arch/x86/xen/smp.h        | 13 ++++++++++
 kernel/cpu.c              |  8 +++++++
 5 files changed, 71 insertions(+), 67 deletions(-)

-- 
2.7.4

[PATCH v2 0/2] Reinstate irq alloc/dealloc locking patch

[Boris Ostrovsky]

Original version of that patch (commit a89941816726) had to be reverted
due to Xen allocating irqs in its cpu_up ops.

The first patch moves allocations into hotplug notifiers and the second
one restores the original patch (with minor adjustments to new hotplug
framework)

This originally went through tip tree but after a couple of failures
reportedby kbuild robot (due to various combinations of CONFIG_SMP and
CONFIG_XEN_PVH) I decided to take it through Xen tree (with config problems
hopefully finally fixed).

Boris Ostrovsky (2):
  xen/x86: Move irq allocation from Xen smp_op.cpu_up()
  hotplug: Prevent alloc/free of irq descriptors during cpu up/down
    (again)

 arch/x86/kernel/smpboot.c | 11 ---------
 arch/x86/xen/enlighten.c  | 61 +++++++++++++++++++++++++++++++++++++----------
 arch/x86/xen/smp.c        | 45 ++--------------------------------
 arch/x86/xen/smp.h        | 13 ++++++++++
 kernel/cpu.c              |  8 +++++++
 5 files changed, 71 insertions(+), 67 deletions(-)

-- 
2.7.4


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Xen-devel@lists.xen.org
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[PATCH v2 1/2] xen/x86: Move irq allocation from Xen smp_op.cpu_up()

[Boris Ostrovsky]

Commit ce0d3c0a6fb1 ("genirq: Revert sparse irq locking around
__cpu_up() and move it to x86 for now") reverted irq locking
introduced by commit a89941816726 ("hotplug: Prevent alloc/free
of irq descriptors during cpu up/down") because of Xen allocating
irqs in both of its cpu_up ops.

We can move those allocations into CPU notifiers so that original
patch can be reinstated.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---

v2: Add ifdef CONFIG_SMP to smp.h

 arch/x86/xen/enlighten.c | 61 +++++++++++++++++++++++++++++++++++++-----------
 arch/x86/xen/smp.c       | 45 ++---------------------------------
 arch/x86/xen/smp.h       | 13 +++++++++++
 3 files changed, 63 insertions(+), 56 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 8ffb089..c7f6b1f9 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -140,6 +140,8 @@ RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
 __read_mostly int xen_have_vector_callback;
 EXPORT_SYMBOL_GPL(xen_have_vector_callback);
 
+static struct notifier_block xen_cpu_notifier;
+
 /*
  * Point at some empty memory to start with. We map the real shared_info
  * page as soon as fixmap is up and running.
@@ -1627,6 +1629,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
 	xen_initial_gdt = &per_cpu(gdt_page, 0);
 
 	xen_smp_init();
+	register_cpu_notifier(&xen_cpu_notifier);
 
 #ifdef CONFIG_ACPI_NUMA
 	/*
@@ -1820,21 +1823,53 @@ static void __init init_hvm_pv_info(void)
 	xen_domain_type = XEN_HVM_DOMAIN;
 }
 
-static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action,
-			      void *hcpu)
+static int xen_cpu_notify(struct notifier_block *self, unsigned long action,
+			 void *hcpu)
 {
 	int cpu = (long)hcpu;
+	int rc;
+
 	switch (action) {
 	case CPU_UP_PREPARE:
-		if (cpu_acpi_id(cpu) != U32_MAX)
-			per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
-		else
-			per_cpu(xen_vcpu_id, cpu) = cpu;
-		xen_vcpu_setup(cpu);
-		if (xen_have_vector_callback) {
-			if (xen_feature(XENFEAT_hvm_safe_pvclock))
-				xen_setup_timer(cpu);
+		if (xen_hvm_domain()) {
+			/*
+			 * 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);
+			}
+
+			if (cpu_acpi_id(cpu) != U32_MAX)
+				per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
+			else
+				per_cpu(xen_vcpu_id, cpu) = cpu;
+			xen_vcpu_setup(cpu);
 		}
+
+		if (xen_pv_domain() ||
+		    (xen_have_vector_callback &&
+		     xen_feature(XENFEAT_hvm_safe_pvclock)))
+			xen_setup_timer(cpu);
+
+		rc = xen_smp_intr_init(cpu);
+		if (rc) {
+			WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
+			     cpu, rc);
+			return NOTIFY_BAD;
+		}
+
+		break;
+	case CPU_ONLINE:
+		xen_init_lock_cpu(cpu);
+		break;
+	case CPU_UP_CANCELED:
+		xen_smp_intr_free(cpu);
+		if (xen_pv_domain() ||
+		    (xen_have_vector_callback &&
+		     xen_feature(XENFEAT_hvm_safe_pvclock)))
+			xen_teardown_timer(cpu);
 		break;
 	default:
 		break;
@@ -1842,8 +1877,8 @@ static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action,
 	return NOTIFY_OK;
 }
 
-static struct notifier_block xen_hvm_cpu_notifier = {
-	.notifier_call	= xen_hvm_cpu_notify,
+static struct notifier_block xen_cpu_notifier = {
+	.notifier_call	= xen_cpu_notify,
 };
 
 #ifdef CONFIG_KEXEC_CORE
@@ -1875,7 +1910,7 @@ static void __init xen_hvm_guest_init(void)
 	if (xen_feature(XENFEAT_hvm_callback_vector))
 		xen_have_vector_callback = 1;
 	xen_hvm_smp_init();
-	register_cpu_notifier(&xen_hvm_cpu_notifier);
+	register_cpu_notifier(&xen_cpu_notifier);
 	xen_unplug_emulated_devices();
 	x86_init.irqs.intr_init = xen_init_IRQ;
 	xen_hvm_init_time_ops();
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 0b4d04c..137afbb 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -115,7 +115,7 @@ asmlinkage __visible void cpu_bringup_and_idle(int cpu)
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 }
 
-static void xen_smp_intr_free(unsigned int cpu)
+void xen_smp_intr_free(unsigned int cpu)
 {
 	if (per_cpu(xen_resched_irq, cpu).irq >= 0) {
 		unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu).irq, NULL);
@@ -159,7 +159,7 @@ static void xen_smp_intr_free(unsigned int cpu)
 		per_cpu(xen_pmu_irq, cpu).name = NULL;
 	}
 };
-static int xen_smp_intr_init(unsigned int cpu)
+int xen_smp_intr_init(unsigned int cpu)
 {
 	int rc;
 	char *resched_name, *callfunc_name, *debug_name, *pmu_name;
@@ -475,8 +475,6 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
 	common_cpu_up(cpu, idle);
 
 	xen_setup_runstate_info(cpu);
-	xen_setup_timer(cpu);
-	xen_init_lock_cpu(cpu);
 
 	/*
 	 * PV VCPUs are always successfully taken down (see 'while' loop
@@ -495,10 +493,6 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
 
 	xen_pmu_init(cpu);
 
-	rc = xen_smp_intr_init(cpu);
-	if (rc)
-		return rc;
-
 	rc = HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL);
 	BUG_ON(rc);
 
@@ -769,47 +763,12 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
 	xen_init_lock_cpu(0);
 }
 
-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
-	 * it is marked online in native_cpu_up().
-	*/
-	rc = xen_smp_intr_init(cpu);
-	WARN_ON(rc);
-	if (!rc)
-		rc =  native_cpu_up(cpu, tidle);
-
-	/*
-	 * We must initialize the slowpath CPU kicker _after_ the native
-	 * path has executed. If we initialized it before none of the
-	 * unlocker IPI kicks would reach the booting CPU as the booting
-	 * CPU had not set itself 'online' in cpu_online_mask. That mask
-	 * is checked when IPIs are sent (on HVM at least).
-	 */
-	xen_init_lock_cpu(cpu);
-	return rc;
-}
-
 void __init xen_hvm_smp_init(void)
 {
 	if (!xen_have_vector_callback)
 		return;
 	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_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;
diff --git a/arch/x86/xen/smp.h b/arch/x86/xen/smp.h
index 963d62a..c5c16dc 100644
--- a/arch/x86/xen/smp.h
+++ b/arch/x86/xen/smp.h
@@ -1,5 +1,6 @@
 #ifndef _XEN_SMP_H
 
+#ifdef CONFIG_SMP
 extern void xen_send_IPI_mask(const struct cpumask *mask,
 			      int vector);
 extern void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
@@ -8,6 +9,18 @@ extern void xen_send_IPI_allbutself(int vector);
 extern void xen_send_IPI_all(int vector);
 extern void xen_send_IPI_self(int vector);
 
+extern int xen_smp_intr_init(unsigned int cpu);
+extern void xen_smp_intr_free(unsigned int cpu);
+
+#else /* CONFIG_SMP */
+
+static inline int xen_smp_intr_init(unsigned int cpu)
+{
+	return 0;
+}
+static inline void xen_smp_intr_free(unsigned int cpu) {}
+#endif /* CONFIG_SMP */
+
 #ifdef CONFIG_XEN_PVH
 extern void xen_pvh_early_cpu_init(int cpu, bool entry);
 #else
-- 
2.7.4

[PATCH v2 1/2] xen/x86: Move irq allocation from Xen smp_op.cpu_up()

[Boris Ostrovsky]

Commit ce0d3c0a6fb1 ("genirq: Revert sparse irq locking around
__cpu_up() and move it to x86 for now") reverted irq locking
introduced by commit a89941816726 ("hotplug: Prevent alloc/free
of irq descriptors during cpu up/down") because of Xen allocating
irqs in both of its cpu_up ops.

We can move those allocations into CPU notifiers so that original
patch can be reinstated.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---

v2: Add ifdef CONFIG_SMP to smp.h

 arch/x86/xen/enlighten.c | 61 +++++++++++++++++++++++++++++++++++++-----------
 arch/x86/xen/smp.c       | 45 ++---------------------------------
 arch/x86/xen/smp.h       | 13 +++++++++++
 3 files changed, 63 insertions(+), 56 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 8ffb089..c7f6b1f9 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -140,6 +140,8 @@ RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
 __read_mostly int xen_have_vector_callback;
 EXPORT_SYMBOL_GPL(xen_have_vector_callback);
 
+static struct notifier_block xen_cpu_notifier;
+
 /*
  * Point at some empty memory to start with. We map the real shared_info
  * page as soon as fixmap is up and running.
@@ -1627,6 +1629,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
 	xen_initial_gdt = &per_cpu(gdt_page, 0);
 
 	xen_smp_init();
+	register_cpu_notifier(&xen_cpu_notifier);
 
 #ifdef CONFIG_ACPI_NUMA
 	/*
@@ -1820,21 +1823,53 @@ static void __init init_hvm_pv_info(void)
 	xen_domain_type = XEN_HVM_DOMAIN;
 }
 
-static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action,
-			      void *hcpu)
+static int xen_cpu_notify(struct notifier_block *self, unsigned long action,
+			 void *hcpu)
 {
 	int cpu = (long)hcpu;
+	int rc;
+
 	switch (action) {
 	case CPU_UP_PREPARE:
-		if (cpu_acpi_id(cpu) != U32_MAX)
-			per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
-		else
-			per_cpu(xen_vcpu_id, cpu) = cpu;
-		xen_vcpu_setup(cpu);
-		if (xen_have_vector_callback) {
-			if (xen_feature(XENFEAT_hvm_safe_pvclock))
-				xen_setup_timer(cpu);
+		if (xen_hvm_domain()) {
+			/*
+			 * 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);
+			}
+
+			if (cpu_acpi_id(cpu) != U32_MAX)
+				per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
+			else
+				per_cpu(xen_vcpu_id, cpu) = cpu;
+			xen_vcpu_setup(cpu);
 		}
+
+		if (xen_pv_domain() ||
+		    (xen_have_vector_callback &&
+		     xen_feature(XENFEAT_hvm_safe_pvclock)))
+			xen_setup_timer(cpu);
+
+		rc = xen_smp_intr_init(cpu);
+		if (rc) {
+			WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
+			     cpu, rc);
+			return NOTIFY_BAD;
+		}
+
+		break;
+	case CPU_ONLINE:
+		xen_init_lock_cpu(cpu);
+		break;
+	case CPU_UP_CANCELED:
+		xen_smp_intr_free(cpu);
+		if (xen_pv_domain() ||
+		    (xen_have_vector_callback &&
+		     xen_feature(XENFEAT_hvm_safe_pvclock)))
+			xen_teardown_timer(cpu);
 		break;
 	default:
 		break;
@@ -1842,8 +1877,8 @@ static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action,
 	return NOTIFY_OK;
 }
 
-static struct notifier_block xen_hvm_cpu_notifier = {
-	.notifier_call	= xen_hvm_cpu_notify,
+static struct notifier_block xen_cpu_notifier = {
+	.notifier_call	= xen_cpu_notify,
 };
 
 #ifdef CONFIG_KEXEC_CORE
@@ -1875,7 +1910,7 @@ static void __init xen_hvm_guest_init(void)
 	if (xen_feature(XENFEAT_hvm_callback_vector))
 		xen_have_vector_callback = 1;
 	xen_hvm_smp_init();
-	register_cpu_notifier(&xen_hvm_cpu_notifier);
+	register_cpu_notifier(&xen_cpu_notifier);
 	xen_unplug_emulated_devices();
 	x86_init.irqs.intr_init = xen_init_IRQ;
 	xen_hvm_init_time_ops();
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 0b4d04c..137afbb 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -115,7 +115,7 @@ asmlinkage __visible void cpu_bringup_and_idle(int cpu)
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 }
 
-static void xen_smp_intr_free(unsigned int cpu)
+void xen_smp_intr_free(unsigned int cpu)
 {
 	if (per_cpu(xen_resched_irq, cpu).irq >= 0) {
 		unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu).irq, NULL);
@@ -159,7 +159,7 @@ static void xen_smp_intr_free(unsigned int cpu)
 		per_cpu(xen_pmu_irq, cpu).name = NULL;
 	}
 };
-static int xen_smp_intr_init(unsigned int cpu)
+int xen_smp_intr_init(unsigned int cpu)
 {
 	int rc;
 	char *resched_name, *callfunc_name, *debug_name, *pmu_name;
@@ -475,8 +475,6 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
 	common_cpu_up(cpu, idle);
 
 	xen_setup_runstate_info(cpu);
-	xen_setup_timer(cpu);
-	xen_init_lock_cpu(cpu);
 
 	/*
 	 * PV VCPUs are always successfully taken down (see 'while' loop
@@ -495,10 +493,6 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
 
 	xen_pmu_init(cpu);
 
-	rc = xen_smp_intr_init(cpu);
-	if (rc)
-		return rc;
-
 	rc = HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL);
 	BUG_ON(rc);
 
@@ -769,47 +763,12 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
 	xen_init_lock_cpu(0);
 }
 
-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
-	 * it is marked online in native_cpu_up().
-	*/
-	rc = xen_smp_intr_init(cpu);
-	WARN_ON(rc);
-	if (!rc)
-		rc =  native_cpu_up(cpu, tidle);
-
-	/*
-	 * We must initialize the slowpath CPU kicker _after_ the native
-	 * path has executed. If we initialized it before none of the
-	 * unlocker IPI kicks would reach the booting CPU as the booting
-	 * CPU had not set itself 'online' in cpu_online_mask. That mask
-	 * is checked when IPIs are sent (on HVM at least).
-	 */
-	xen_init_lock_cpu(cpu);
-	return rc;
-}
-
 void __init xen_hvm_smp_init(void)
 {
 	if (!xen_have_vector_callback)
 		return;
 	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_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;
diff --git a/arch/x86/xen/smp.h b/arch/x86/xen/smp.h
index 963d62a..c5c16dc 100644
--- a/arch/x86/xen/smp.h
+++ b/arch/x86/xen/smp.h
@@ -1,5 +1,6 @@
 #ifndef _XEN_SMP_H
 
+#ifdef CONFIG_SMP
 extern void xen_send_IPI_mask(const struct cpumask *mask,
 			      int vector);
 extern void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
@@ -8,6 +9,18 @@ extern void xen_send_IPI_allbutself(int vector);
 extern void xen_send_IPI_all(int vector);
 extern void xen_send_IPI_self(int vector);
 
+extern int xen_smp_intr_init(unsigned int cpu);
+extern void xen_smp_intr_free(unsigned int cpu);
+
+#else /* CONFIG_SMP */
+
+static inline int xen_smp_intr_init(unsigned int cpu)
+{
+	return 0;
+}
+static inline void xen_smp_intr_free(unsigned int cpu) {}
+#endif /* CONFIG_SMP */
+
 #ifdef CONFIG_XEN_PVH
 extern void xen_pvh_early_cpu_init(int cpu, bool entry);
 #else
-- 
2.7.4


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Re: [PATCH v2 1/2] xen/x86: Move irq allocation from Xen smp_op.cpu_up()

[Juergen Gross]

On 03/08/16 19:22, Boris Ostrovsky wrote:
> Commit ce0d3c0a6fb1 ("genirq: Revert sparse irq locking around
> __cpu_up() and move it to x86 for now") reverted irq locking
> introduced by commit a89941816726 ("hotplug: Prevent alloc/free
> of irq descriptors during cpu up/down") because of Xen allocating
> irqs in both of its cpu_up ops.
> 
> We can move those allocations into CPU notifiers so that original
> patch can be reinstated.
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel

Re: [PATCH v2 1/2] xen/x86: Move irq allocation from Xen smp_op.cpu_up()

[Juergen Gross]

On 03/08/16 19:22, Boris Ostrovsky wrote:
> Commit ce0d3c0a6fb1 ("genirq: Revert sparse irq locking around
> __cpu_up() and move it to x86 for now") reverted irq locking
> introduced by commit a89941816726 ("hotplug: Prevent alloc/free
> of irq descriptors during cpu up/down") because of Xen allocating
> irqs in both of its cpu_up ops.
> 
> We can move those allocations into CPU notifiers so that original
> patch can be reinstated.
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen

[PATCH v2 2/2] hotplug: Prevent alloc/free of irq descriptors during cpu up/down (again)

[Boris Ostrovsky]

Now that Xen no longer allocates irqs in _cpu_up() we can restore
commit a89941816726 ("hotplug: Prevent alloc/free of irq descriptors
during cpu up/down")

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
CC: x86@kernel.org
CC: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/kernel/smpboot.c | 11 -----------
 kernel/cpu.c              |  8 ++++++++
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2a6e84a..067de61 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1108,17 +1108,8 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 
 	common_cpu_up(cpu, tidle);
 
-	/*
-	 * We have to walk the irq descriptors to setup the vector
-	 * space for the cpu which comes online.  Prevent irq
-	 * alloc/free across the bringup.
-	 */
-	irq_lock_sparse();
-
 	err = do_boot_cpu(apicid, cpu, tidle);
-
 	if (err) {
-		irq_unlock_sparse();
 		pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu);
 		return -EIO;
 	}
@@ -1136,8 +1127,6 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 		touch_nmi_watchdog();
 	}
 
-	irq_unlock_sparse();
-
 	return 0;
 }
 
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 341bf80..ec12b72 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -349,8 +349,16 @@ static int bringup_cpu(unsigned int cpu)
 	struct task_struct *idle = idle_thread_get(cpu);
 	int ret;
 
+	/*
+	 * Some architectures have to walk the irq descriptors to
+	 * setup the vector space for the cpu which comes online.
+	 * Prevent irq alloc/free across the bringup.
+	 */
+	irq_lock_sparse();
+
 	/* Arch-specific enabling code. */
 	ret = __cpu_up(cpu, idle);
+	irq_unlock_sparse();
 	if (ret) {
 		cpu_notify(CPU_UP_CANCELED, cpu);
 		return ret;
-- 
2.7.4

[PATCH v2 2/2] hotplug: Prevent alloc/free of irq descriptors during cpu up/down (again)

[Boris Ostrovsky]

Now that Xen no longer allocates irqs in _cpu_up() we can restore
commit a89941816726 ("hotplug: Prevent alloc/free of irq descriptors
during cpu up/down")

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
CC: x86@kernel.org
CC: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/kernel/smpboot.c | 11 -----------
 kernel/cpu.c              |  8 ++++++++
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2a6e84a..067de61 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1108,17 +1108,8 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 
 	common_cpu_up(cpu, tidle);
 
-	/*
-	 * We have to walk the irq descriptors to setup the vector
-	 * space for the cpu which comes online.  Prevent irq
-	 * alloc/free across the bringup.
-	 */
-	irq_lock_sparse();
-
 	err = do_boot_cpu(apicid, cpu, tidle);
-
 	if (err) {
-		irq_unlock_sparse();
 		pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu);
 		return -EIO;
 	}
@@ -1136,8 +1127,6 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 		touch_nmi_watchdog();
 	}
 
-	irq_unlock_sparse();
-
 	return 0;
 }
 
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 341bf80..ec12b72 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -349,8 +349,16 @@ static int bringup_cpu(unsigned int cpu)
 	struct task_struct *idle = idle_thread_get(cpu);
 	int ret;
 
+	/*
+	 * Some architectures have to walk the irq descriptors to
+	 * setup the vector space for the cpu which comes online.
+	 * Prevent irq alloc/free across the bringup.
+	 */
+	irq_lock_sparse();
+
 	/* Arch-specific enabling code. */
 	ret = __cpu_up(cpu, idle);
+	irq_unlock_sparse();
 	if (ret) {
 		cpu_notify(CPU_UP_CANCELED, cpu);
 		return ret;
-- 
2.7.4


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel

Re: [PATCH v2 2/2] hotplug: Prevent alloc/free of irq descriptors during cpu up/down (again)

[Juergen Gross]

On 03/08/16 19:22, Boris Ostrovsky wrote:
> Now that Xen no longer allocates irqs in _cpu_up() we can restore
> commit a89941816726 ("hotplug: Prevent alloc/free of irq descriptors
> during cpu up/down")
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Acked-by: Thomas Gleixner <tglx@linutronix.de>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel

Re: [PATCH v2 2/2] hotplug: Prevent alloc/free of irq descriptors during cpu up/down (again)

[Juergen Gross]

On 03/08/16 19:22, Boris Ostrovsky wrote:
> Now that Xen no longer allocates irqs in _cpu_up() we can restore
> commit a89941816726 ("hotplug: Prevent alloc/free of irq descriptors
> during cpu up/down")
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Acked-by: Thomas Gleixner <tglx@linutronix.de>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen

[tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[tip-bot for Boris Ostrovsky]

Commit-ID:  aa877175e7a9982233ed8f10cb4bfddd78d82741
Gitweb:     http://git.kernel.org/tip/aa877175e7a9982233ed8f10cb4bfddd78d82741
Author:     Boris Ostrovsky <boris.ostrovsky@oracle.com>
AuthorDate: Wed, 3 Aug 2016 13:22:28 -0400
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 10 Aug 2016 15:42:57 +0200

cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

Now that Xen no longer allocates irqs in _cpu_up() we can restore
commit:

  a89941816726 ("hotplug: Prevent alloc/free of irq descriptors during cpu up/down")

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: david.vrabel@citrix.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1470244948-17674-3-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/smpboot.c | 11 -----------
 kernel/cpu.c              |  8 ++++++++
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2a6e84a..067de61 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1108,17 +1108,8 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 
 	common_cpu_up(cpu, tidle);
 
-	/*
-	 * We have to walk the irq descriptors to setup the vector
-	 * space for the cpu which comes online.  Prevent irq
-	 * alloc/free across the bringup.
-	 */
-	irq_lock_sparse();
-
 	err = do_boot_cpu(apicid, cpu, tidle);
-
 	if (err) {
-		irq_unlock_sparse();
 		pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu);
 		return -EIO;
 	}
@@ -1136,8 +1127,6 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 		touch_nmi_watchdog();
 	}
 
-	irq_unlock_sparse();
-
 	return 0;
 }
 
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 341bf80..ec12b72 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -349,8 +349,16 @@ static int bringup_cpu(unsigned int cpu)
 	struct task_struct *idle = idle_thread_get(cpu);
 	int ret;
 
+	/*
+	 * Some architectures have to walk the irq descriptors to
+	 * setup the vector space for the cpu which comes online.
+	 * Prevent irq alloc/free across the bringup.
+	 */
+	irq_lock_sparse();
+
 	/* Arch-specific enabling code. */
 	ret = __cpu_up(cpu, idle);
+	irq_unlock_sparse();
 	if (ret) {
 		cpu_notify(CPU_UP_CANCELED, cpu);
 		return ret;

Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[Boris Ostrovsky]

On 08/10/2016 02:10 PM, tip-bot for Boris Ostrovsky wrote:
> Commit-ID:  aa877175e7a9982233ed8f10cb4bfddd78d82741
> Gitweb:     http://git.kernel.org/tip/aa877175e7a9982233ed8f10cb4bfddd78d82741
> Author:     Boris Ostrovsky <boris.ostrovsky@oracle.com>
> AuthorDate: Wed, 3 Aug 2016 13:22:28 -0400
> Committer:  Ingo Molnar <mingo@kernel.org>
> CommitDate: Wed, 10 Aug 2016 15:42:57 +0200
> 
> cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)
> 
> Now that Xen no longer allocates irqs in _cpu_up() we can restore
> commit:
> 
>   a89941816726 ("hotplug: Prevent alloc/free of irq descriptors during cpu up/down")
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Reviewed-by: Juergen Gross <jgross@suse.com>
> Acked-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Cc: david.vrabel@citrix.com
> Cc: xen-devel@lists.xenproject.org
> Link: http://lkml.kernel.org/r/1470244948-17674-3-git-send-email-boris.ostrovsky@oracle.com
> Signed-off-by: Ingo Molnar <mingo@kernel.org>



Since this patch requires
http://marc.info/?l=xen-devel&m=147024499722041&w=2 it may be better to
take it via Xen tree.

-boris

Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[Sebastian Andrzej Siewior]

On 2016-08-11 08:53:31 [-0400], Boris Ostrovsky wrote:
> Since this patch requires
> http://marc.info/?l=xen-devel&m=147024499722041&w=2 it may be better to
> take it via Xen tree.

Why are you adding more register_cpu_notifier() users?

> -boris

Sebastian

Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[Boris Ostrovsky]

On 08/11/2016 09:20 AM, Sebastian Andrzej Siewior wrote:
> On 2016-08-11 08:53:31 [-0400], Boris Ostrovsky wrote:
>> Since this patch requires
>> http://marc.info/?l=xen-devel&m=147024499722041&w=2 it may be better to
>> take it via Xen tree.
> 
> Why are you adding more register_cpu_notifier() users?


Are you asking why this is not using new hotplug infrastructure?

This should indeed be done but not as part of this series. Here we are
solving a specific problem and part of this is allowing PV guests use
the same notifier that HVM guests already do.


-boris

Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[Sebastian Andrzej Siewior]

On 2016-08-11 10:11:20 [-0400], Boris Ostrovsky wrote:
> Are you asking why this is not using new hotplug infrastructure?
correct.

> This should indeed be done but not as part of this series. Here we are
> solving a specific problem and part of this is allowing PV guests use
> the same notifier that HVM guests already do.

I have a huge a series (1285 patches to be exact) which converts the
remaining users away and you are adding new ones.
Is this patch of yours going stable?

> -boris

Sebastian

Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[Boris Ostrovsky]

On 08/11/2016 10:17 AM, Sebastian Andrzej Siewior wrote:
> On 2016-08-11 10:11:20 [-0400], Boris Ostrovsky wrote:
>> Are you asking why this is not using new hotplug infrastructure?
> correct.
> 
>> This should indeed be done but not as part of this series. Here we are
>> solving a specific problem and part of this is allowing PV guests use
>> the same notifier that HVM guests already do.
> 
> I have a huge a series (1285 patches to be exact) which converts the
> remaining users away and you are adding new ones.


So you must have converted Xen code already then? Can you post those
patches (not all 1285, just Xen-related, assuming there are no
dependencies) and I'll see if I can add them to this series?


> Is this patch of yours going stable?

No.

-boris

Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[Sebastian Andrzej Siewior]

On 2016-08-11 10:30:57 [-0400], Boris Ostrovsky wrote:
> So you must have converted Xen code already then? Can you post those
> patches (not all 1285, just Xen-related, assuming there are no
> dependencies) and I'll see if I can add them to this series?

This is patch 77. I *hope* the only clash (if any) will be in
cpuhotplug.h. I did not yet retest things in terms of apply & compile.
I plan to do so within this + next week. If you want to test it right
away, please do so :)

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 4 Nov 2015 21:06:00 +0100
Subject: [PATCH] xen: events: fifo: Convert to hotplug state machine

Install the callbacks via the state machine. In theory we could remove the
upper call evtchn_fifo_alloc_control_block() and have callback invoked for
all online CPUs but this does not reflect the currect code.

Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: xen-devel@lists.xenproject.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/xen/events/events_fifo.c |   33 +++++++++++----------------------
 include/linux/cpuhotplug.h       |    1 +
 2 files changed, 12 insertions(+), 22 deletions(-)

--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -418,30 +418,18 @@ static int evtchn_fifo_alloc_control_blo
 	return ret;
 }
 
-static int evtchn_fifo_cpu_notification(struct notifier_block *self,
-						  unsigned long action,
-						  void *hcpu)
+static int xen_evtchn_cpu_prepare(unsigned int cpu)
 {
-	int cpu = (long)hcpu;
-	int ret = 0;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-		if (!per_cpu(cpu_control_block, cpu))
-			ret = evtchn_fifo_alloc_control_block(cpu);
-		break;
-	case CPU_DEAD:
-		__evtchn_fifo_handle_events(cpu, true);
-		break;
-	default:
-		break;
-	}
-	return ret < 0 ? NOTIFY_BAD : NOTIFY_OK;
+	if (!per_cpu(cpu_control_block, cpu))
+		return evtchn_fifo_alloc_control_block(cpu);
+	return 0;
 }
 
-static struct notifier_block evtchn_fifo_cpu_notifier = {
-	.notifier_call	= evtchn_fifo_cpu_notification,
-};
+static int xen_evtchn_cpu_dead(unsigned int cpu)
+{
+	__evtchn_fifo_handle_events(cpu, true);
+	return 0;
+}
 
 int __init xen_evtchn_fifo_init(void)
 {
@@ -456,7 +444,8 @@ int __init xen_evtchn_fifo_init(void)
 
 	evtchn_ops = &evtchn_ops_fifo;
 
-	register_cpu_notifier(&evtchn_fifo_cpu_notifier);
+	cpuhp_setup_state_nocalls(CPUHP_XEN_EV_PREPEARE, "XEN_EV_PREPEARE",
+				  xen_evtchn_cpu_prepare, xen_evtchn_cpu_dead);
 out:
 	put_cpu();
 	return ret;
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -22,6 +22,7 @@ enum cpuhp_state {
 	CPUHP_SMPCFD_PREPARE,
 	CPUHP_RELAY_PREPARE,
 	CPUHP_SLAB_PREPARE,
+	CPUHP_XEN_EV_PREPEARE,
 	CPUHP_TIMERS_DEAD,
 	CPUHP_SLUB_DEAD,
 	CPUHP_MM_WRITEBACK_DEAD,


Sebastian

Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[Boris Ostrovsky]

On 08/11/2016 10:44 AM, Sebastian Andrzej Siewior wrote:
> On 2016-08-11 10:30:57 [-0400], Boris Ostrovsky wrote:
>> So you must have converted Xen code already then? Can you post those
>> patches (not all 1285, just Xen-related, assuming there are no
>> dependencies) and I'll see if I can add them to this series?
> 
> This is patch 77. I *hope* the only clash (if any) will be in
> cpuhotplug.h. I did not yet retest things in terms of apply & compile.
> I plan to do so within this + next week. If you want to test it right
> away, please do so :)
> 
> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Date: Wed, 4 Nov 2015 21:06:00 +0100
> Subject: [PATCH] xen: events: fifo: Convert to hotplug state machine
> 
> Install the callbacks via the state machine. In theory we could remove the
> upper call evtchn_fifo_alloc_control_block() and have callback invoked for
> all online CPUs but this does not reflect the currect code.
> 
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: David Vrabel <david.vrabel@citrix.com>
> Cc: xen-devel@lists.xenproject.org
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>  drivers/xen/events/events_fifo.c |   33 +++++++++++----------------------
>  include/linux/cpuhotplug.h       |    1 +
>  2 files changed, 12 insertions(+), 22 deletions(-)


I was actually looking for arch/x86/xen/enlighten.c patch but if you
don't have it I can do it myself.


> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -22,6 +22,7 @@ enum cpuhp_state {
>  	CPUHP_SMPCFD_PREPARE,
>  	CPUHP_RELAY_PREPARE,
>  	CPUHP_SLAB_PREPARE,
> +	CPUHP_XEN_EV_PREPEARE,

Misspelled PREPARE.

-boris

Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq descriptors during CPU up/down (again)

[Sebastian Andrzej Siewior]

On 2016-08-11 11:06:29 [-0400], Boris Ostrovsky wrote:
> I was actually looking for arch/x86/xen/enlighten.c patch but if you
> don't have it I can do it myself.

I'm sorry. I had it but it got removed by accident during the refresh.
This is an older version so you have an idea :)

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 4 Nov 2015 21:06:01 +0100
Subject: [PATCH] x86: xen: Convert to hotplug state machine

Install the callbacks via the state machine.

Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/x86/xen/enlighten.c   |   28 +++++++++-------------------
 include/linux/cpuhotplug.h |    1 +
 2 files changed, 10 insertions(+), 19 deletions(-)

--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1802,28 +1802,16 @@ static void __init init_hvm_pv_info(void
 	xen_domain_type = XEN_HVM_DOMAIN;
 }
 
-static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action,
-			      void *hcpu)
+static int xen_hvm_cpu_up_prepare(unsigned int cpu)
 {
-	int cpu = (long)hcpu;
-	switch (action) {
-	case CPU_UP_PREPARE:
-		xen_vcpu_setup(cpu);
-		if (xen_have_vector_callback) {
-			if (xen_feature(XENFEAT_hvm_safe_pvclock))
-				xen_setup_timer(cpu);
-		}
-		break;
-	default:
-		break;
+	xen_vcpu_setup(cpu);
+	if (xen_have_vector_callback) {
+		if (xen_feature(XENFEAT_hvm_safe_pvclock))
+			xen_setup_timer(cpu);
 	}
-	return NOTIFY_OK;
+	return 0;
 }
 
-static struct notifier_block xen_hvm_cpu_notifier = {
-	.notifier_call	= xen_hvm_cpu_notify,
-};
-
 #ifdef CONFIG_KEXEC_CORE
 static void xen_hvm_shutdown(void)
 {
@@ -1853,7 +1841,9 @@ static void __init xen_hvm_guest_init(vo
 	if (xen_feature(XENFEAT_hvm_callback_vector))
 		xen_have_vector_callback = 1;
 	xen_hvm_smp_init();
-	register_cpu_notifier(&xen_hvm_cpu_notifier);
+	cpuhp_setup_state_nocalls(CPUHP_XEN_HVM_GUEST_PREPARE,
+				  "XEN_HVM_GUEST_PREPARE",
+				  xen_hvm_cpu_up_prepare, NULL);
 	xen_unplug_emulated_devices();
 	x86_init.irqs.intr_init = xen_init_IRQ;
 	xen_hvm_init_time_ops();
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -24,6 +24,7 @@ enum cpuhp_state {
 	CPUHP_RELAY_PREPARE,
 	CPUHP_SLAB_PREPARE,
 	CPUHP_XEN_EV_PREPEARE,
+	CPUHP_XEN_HVM_GUEST_PREPARE,
 	CPUHP_MD_RAID5_PREPARE,
 	CPUHP_CPUIDLE_COUPLED_PREPARE,
 	CPUHP_TIMERS_DEAD,

Sebastian

Re: [Xen-devel] [PATCH v2 0/2] Reinstate irq alloc/dealloc locking patch

[David Vrabel]

On 03/08/16 18:22, Boris Ostrovsky wrote:
> Original version of that patch (commit a89941816726) had to be reverted
> due to Xen allocating irqs in its cpu_up ops.
> 
> The first patch moves allocations into hotplug notifiers and the second
> one restores the original patch (with minor adjustments to new hotplug
> framework)
> 
> This originally went through tip tree but after a couple of failures
> reportedby kbuild robot (due to various combinations of CONFIG_SMP and
> CONFIG_XEN_PVH) I decided to take it through Xen tree (with config problems
> hopefully finally fixed).

Applied to for-linus-4.9, thanks.

David

Re: [PATCH v2 0/2] Reinstate irq alloc/dealloc locking patch

[David Vrabel]

On 03/08/16 18:22, Boris Ostrovsky wrote:
> Original version of that patch (commit a89941816726) had to be reverted
> due to Xen allocating irqs in its cpu_up ops.
> 
> The first patch moves allocations into hotplug notifiers and the second
> one restores the original patch (with minor adjustments to new hotplug
> framework)
> 
> This originally went through tip tree but after a couple of failures
> reportedby kbuild robot (due to various combinations of CONFIG_SMP and
> CONFIG_XEN_PVH) I decided to take it through Xen tree (with config problems
> hopefully finally fixed).

Applied to for-linus-4.9, thanks.

David

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