[patch 0/3] genirq/x86: Cure CPU hotplug vector accounting woes

[patch 0/3] genirq/x86: Cure CPU hotplug vector accounting woes

[Thomas Gleixner]

Yuriy reported suspend/resume issues related to the irq vector management.

They turned out to be an accounting issue related to CPU hot unplug where
vectors which are allocated on unplugged CPUs are dropped from the
accounting because not started interrupts are not force migrated.

The following patch series addresses the issues and makes accounting work
correctly again.

Thanks,

	tglx

[patch 1/3] genirq/matrix: Handle CPU offlining proper

[Thomas Gleixner]

[-- Attachment #1: genirq-matrix--Handle-CPU-offlining-proper.patch --]
[-- Type: text/plain, Size: 2402 bytes --]

At CPU hotunplug the corresponding per cpu matrix allocator is shut down and
the allocated interrupt bits are discarded under the assumption that all
allocated bits have been either migrated away or shut down through the
managed interrupts mechanism.

This is not true because interrupts which are not started up might have a
vector allocated on the outgoing CPU. When the interrupt is started up
later or completely shutdown and freed then the allocated vector is handed
back, triggering warnings or causing accounting issues which result in
suspend failures and other issues.

Change the CPU hotplug mechanism of the matrix allocator so that the
remaining allocations at unplug time are preserved and global accounting at
hotplug is correctly readjusted to take the dormant vectors into account.

Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator")
Reported-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Cc: stable@vger.kernel.org
---
 kernel/irq/matrix.c |   23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

--- a/kernel/irq/matrix.c
+++ b/kernel/irq/matrix.c
@@ -16,6 +16,7 @@ struct cpumap {
 	unsigned int		available;
 	unsigned int		allocated;
 	unsigned int		managed;
+	bool			initialized;
 	bool			online;
 	unsigned long		alloc_map[IRQ_MATRIX_SIZE];
 	unsigned long		managed_map[IRQ_MATRIX_SIZE];
@@ -81,9 +82,11 @@ void irq_matrix_online(struct irq_matrix
 
 	BUG_ON(cm->online);
 
-	bitmap_zero(cm->alloc_map, m->matrix_bits);
-	cm->available = m->alloc_size - (cm->managed + m->systembits_inalloc);
-	cm->allocated = 0;
+	if (!cm->initialized) {
+		cm->available = m->alloc_size;
+		cm->available -= cm->managed + m->systembits_inalloc;
+		cm->initialized = true;
+	}
 	m->global_available += cm->available;
 	cm->online = true;
 	m->online_maps++;
@@ -370,14 +373,16 @@ void irq_matrix_free(struct irq_matrix *
 	if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
 		return;
 
-	if (cm->online) {
-		clear_bit(bit, cm->alloc_map);
-		cm->allocated--;
+	clear_bit(bit, cm->alloc_map);
+	cm->allocated--;
+
+	if (cm->online)
 		m->total_allocated--;
-		if (!managed) {
-			cm->available++;
+
+	if (!managed) {
+		cm->available++;
+		if (cm->online)
 			m->global_available++;
-		}
 	}
 	trace_irq_matrix_free(bit, cpu, m, cm);
 }

[patch 2/3] x86/apic/vector: Handle vector release on CPU unplug correctly

[Thomas Gleixner]

[-- Attachment #1: x86-apic-vector--Handle-vector-release-on-CPU-unplug-correctly.patch --]
[-- Type: text/plain, Size: 2437 bytes --]

When a irq vector is replaced, then the previous vector is normally
released when the first interrupt happens on the new vector. If the target
CPU of the previous vector is already offline when the new vector is
installed, then the previous vector is silently discarded, which leads to
accounting issues causing suspend failures and other problems.

Adjust the logic so that the previous vector is freed in the underlying
matrix allocator to ensure that the accounting stays correct.

Fixes: 69cde0004a4b ("x86/vector: Use matrix allocator for vector assignment")
Reported-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Cc: stable@vger.kernel.org
---
 arch/x86/kernel/apic/vector.c |   22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -134,21 +134,39 @@ static void apic_update_vector(struct ir
 {
 	struct apic_chip_data *apicd = apic_chip_data(irqd);
 	struct irq_desc *desc = irq_data_to_desc(irqd);
+	bool managed = irqd_affinity_is_managed(irqd);
 
 	lockdep_assert_held(&vector_lock);
 
 	trace_vector_update(irqd->irq, newvec, newcpu, apicd->vector,
 			    apicd->cpu);
 
-	/* Setup the vector move, if required  */
-	if (apicd->vector && cpu_online(apicd->cpu)) {
+	/*
+	 * If there is no vector associated or if the associated vector is
+	 * the shutdown vector, which is associated to make PCI/MSI
+	 * shutdown mode work, then there is nothing to release.
+	 */
+	if (!apic->vector || apicd->vector == MANAGED_IRQ_SHUTDOWN_VECTOR)
+		goto setnew;
+	/*
+	 * If the target CPU of the previous vector is online, then mark
+	 * the vector as move in progress and store it for cleanup when the
+	 * first interrupt on the new vector arrives. If the target CPU is
+	 * offline then the regular release mechanism via the cleanup
+	 * vector is not possible and the vector can be immediately freed
+	 * in the underlying matrix allocator.
+	 */
+	if (cpu_online(apicd->cpu)) {
 		apicd->move_in_progress = true;
 		apicd->prev_vector = apicd->vector;
 		apicd->prev_cpu = apicd->cpu;
 	} else {
+		irq_matrix_free(vector_matrix, apicd->cpu, apicd->vector,
+				managed);
 		apicd->prev_vector = 0;
 	}
 
+setnew:
 	apicd->vector = newvec;
 	apicd->cpu = newcpu;
 	BUG_ON(!IS_ERR_OR_NULL(per_cpu(vector_irq, newcpu)[newvec]));

[patch 3/3] x

[Thomas Gleixner]

[-- Attachment #1: x.patch --]
[-- Type: text/plain, Size: 776 bytes --]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/irq/manage.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -855,10 +855,14 @@ irq_thread_check_affinity(struct irq_des
 	 * This code is triggered unconditionally. Check the affinity
 	 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
 	 */
-	if (cpumask_available(desc->irq_common_data.affinity))
-		cpumask_copy(mask, desc->irq_common_data.affinity);
-	else
+	if (cpumask_available(desc->irq_common_data.affinity)) {
+		const struct cpumask *m;
+
+		m = irq_data_get_effective_affinity_mask(&desc->irq_data);
+		cpumask_copy(mask, m);
+	} else {
 		valid = false;
+	}
 	raw_spin_unlock_irq(&desc->lock);
 
 	if (valid)

Re: [patch 3/3] x

[Thomas Gleixner]

Bah, scratch that. That's a different story and I missed to remove that
patch from the quilt series.....

On Thu, 22 Feb 2018, Thomas Gleixner wrote:

> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  kernel/irq/manage.c |   10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -855,10 +855,14 @@ irq_thread_check_affinity(struct irq_des
>  	 * This code is triggered unconditionally. Check the affinity
>  	 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
>  	 */
> -	if (cpumask_available(desc->irq_common_data.affinity))
> -		cpumask_copy(mask, desc->irq_common_data.affinity);
> -	else
> +	if (cpumask_available(desc->irq_common_data.affinity)) {
> +		const struct cpumask *m;
> +
> +		m = irq_data_get_effective_affinity_mask(&desc->irq_data);
> +		cpumask_copy(mask, m);
> +	} else {
>  		valid = false;
> +	}
>  	raw_spin_unlock_irq(&desc->lock);
>  
>  	if (valid)
> 
> 
> 

[tip:x86/urgent] genirq/matrix: Handle CPU offlining proper

[tip-bot for Thomas Gleixner]

Commit-ID:  651ca2c00405a2ae3870cc0b4f15a182eb6fbe26
Gitweb:     https://git.kernel.org/tip/651ca2c00405a2ae3870cc0b4f15a182eb6fbe26
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 22 Feb 2018 12:08:05 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 22 Feb 2018 22:05:43 +0100

genirq/matrix: Handle CPU offlining proper

At CPU hotunplug the corresponding per cpu matrix allocator is shut down and
the allocated interrupt bits are discarded under the assumption that all
allocated bits have been either migrated away or shut down through the
managed interrupts mechanism.

This is not true because interrupts which are not started up might have a
vector allocated on the outgoing CPU. When the interrupt is started up
later or completely shutdown and freed then the allocated vector is handed
back, triggering warnings or causing accounting issues which result in
suspend failures and other issues.

Change the CPU hotplug mechanism of the matrix allocator so that the
remaining allocations at unplug time are preserved and global accounting at
hotplug is correctly readjusted to take the dormant vectors into account.

Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator")
Reported-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180222112316.849980972@linutronix.de

---
 kernel/irq/matrix.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c
index 5187dfe..4c57704 100644
--- a/kernel/irq/matrix.c
+++ b/kernel/irq/matrix.c
@@ -16,6 +16,7 @@ struct cpumap {
 	unsigned int		available;
 	unsigned int		allocated;
 	unsigned int		managed;
+	bool			initialized;
 	bool			online;
 	unsigned long		alloc_map[IRQ_MATRIX_SIZE];
 	unsigned long		managed_map[IRQ_MATRIX_SIZE];
@@ -81,9 +82,11 @@ void irq_matrix_online(struct irq_matrix *m)
 
 	BUG_ON(cm->online);
 
-	bitmap_zero(cm->alloc_map, m->matrix_bits);
-	cm->available = m->alloc_size - (cm->managed + m->systembits_inalloc);
-	cm->allocated = 0;
+	if (!cm->initialized) {
+		cm->available = m->alloc_size;
+		cm->available -= cm->managed + m->systembits_inalloc;
+		cm->initialized = true;
+	}
 	m->global_available += cm->available;
 	cm->online = true;
 	m->online_maps++;
@@ -370,14 +373,16 @@ void irq_matrix_free(struct irq_matrix *m, unsigned int cpu,
 	if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
 		return;
 
-	if (cm->online) {
-		clear_bit(bit, cm->alloc_map);
-		cm->allocated--;
+	clear_bit(bit, cm->alloc_map);
+	cm->allocated--;
+
+	if (cm->online)
 		m->total_allocated--;
-		if (!managed) {
-			cm->available++;
+
+	if (!managed) {
+		cm->available++;
+		if (cm->online)
 			m->global_available++;
-		}
 	}
 	trace_irq_matrix_free(bit, cpu, m, cm);
 }

[tip:x86/urgent] x86/apic/vector: Handle vector release on CPU unplug correctly

[tip-bot for Thomas Gleixner]

Commit-ID:  f60606c4ce402963dc552c62910ffa7080b4a628
Gitweb:     https://git.kernel.org/tip/f60606c4ce402963dc552c62910ffa7080b4a628
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 22 Feb 2018 12:08:06 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 22 Feb 2018 22:05:44 +0100

x86/apic/vector: Handle vector release on CPU unplug correctly

When a irq vector is replaced, then the previous vector is normally
released when the first interrupt happens on the new vector. If the target
CPU of the previous vector is already offline when the new vector is
installed, then the previous vector is silently discarded, which leads to
accounting issues causing suspend failures and other problems.

Adjust the logic so that the previous vector is freed in the underlying
matrix allocator to ensure that the accounting stays correct.

Fixes: 69cde0004a4b ("x86/vector: Use matrix allocator for vector assignment")
Reported-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180222112316.930791749@linutronix.de

---
 arch/x86/kernel/apic/vector.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 3cc471b..a82ea2e 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -134,21 +134,40 @@ static void apic_update_vector(struct irq_data *irqd, unsigned int newvec,
 {
 	struct apic_chip_data *apicd = apic_chip_data(irqd);
 	struct irq_desc *desc = irq_data_to_desc(irqd);
+	bool managed = irqd_affinity_is_managed(irqd);
 
 	lockdep_assert_held(&vector_lock);
 
 	trace_vector_update(irqd->irq, newvec, newcpu, apicd->vector,
 			    apicd->cpu);
 
-	/* Setup the vector move, if required  */
-	if (apicd->vector && cpu_online(apicd->cpu)) {
+	/*
+	 * If there is no vector associated or if the associated vector is
+	 * the shutdown vector, which is associated to make PCI/MSI
+	 * shutdown mode work, then there is nothing to release. Clear out
+	 * prev_vector for this and the offlined target case.
+	 */
+	apicd->prev_vector = 0;
+	if (!apic->vector || apicd->vector == MANAGED_IRQ_SHUTDOWN_VECTOR)
+		goto setnew;
+	/*
+	 * If the target CPU of the previous vector is online, then mark
+	 * the vector as move in progress and store it for cleanup when the
+	 * first interrupt on the new vector arrives. If the target CPU is
+	 * offline then the regular release mechanism via the cleanup
+	 * vector is not possible and the vector can be immediately freed
+	 * in the underlying matrix allocator.
+	 */
+	if (cpu_online(apicd->cpu)) {
 		apicd->move_in_progress = true;
 		apicd->prev_vector = apicd->vector;
 		apicd->prev_cpu = apicd->cpu;
 	} else {
-		apicd->prev_vector = 0;
+		irq_matrix_free(vector_matrix, apicd->cpu, apicd->vector,
+				managed);
 	}
 
+setnew:
 	apicd->vector = newvec;
 	apicd->cpu = newcpu;
 	BUG_ON(!IS_ERR_OR_NULL(per_cpu(vector_irq, newcpu)[newvec]));

[tip:x86/urgent] x86/apic/vector: Handle vector release on CPU unplug correctly

[tip-bot for Thomas Gleixner]

Commit-ID:  c16721c5cece64bfe12cdc302a0228026d8089d7
Gitweb:     https://git.kernel.org/tip/c16721c5cece64bfe12cdc302a0228026d8089d7
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 22 Feb 2018 12:08:06 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 22 Feb 2018 22:25:50 +0100

x86/apic/vector: Handle vector release on CPU unplug correctly

When a irq vector is replaced, then the previous vector is normally
released when the first interrupt happens on the new vector. If the target
CPU of the previous vector is already offline when the new vector is
installed, then the previous vector is silently discarded, which leads to
accounting issues causing suspend failures and other problems.

Adjust the logic so that the previous vector is freed in the underlying
matrix allocator to ensure that the accounting stays correct.

Fixes: 69cde0004a4b ("x86/vector: Use matrix allocator for vector assignment")
Reported-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180222112316.930791749@linutronix.de
---
 arch/x86/kernel/apic/vector.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 3cc471b..a82ea2e 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -134,21 +134,40 @@ static void apic_update_vector(struct irq_data *irqd, unsigned int newvec,
 {
 	struct apic_chip_data *apicd = apic_chip_data(irqd);
 	struct irq_desc *desc = irq_data_to_desc(irqd);
+	bool managed = irqd_affinity_is_managed(irqd);
 
 	lockdep_assert_held(&vector_lock);
 
 	trace_vector_update(irqd->irq, newvec, newcpu, apicd->vector,
 			    apicd->cpu);
 
-	/* Setup the vector move, if required  */
-	if (apicd->vector && cpu_online(apicd->cpu)) {
+	/*
+	 * If there is no vector associated or if the associated vector is
+	 * the shutdown vector, which is associated to make PCI/MSI
+	 * shutdown mode work, then there is nothing to release. Clear out
+	 * prev_vector for this and the offlined target case.
+	 */
+	apicd->prev_vector = 0;
+	if (!apic->vector || apicd->vector == MANAGED_IRQ_SHUTDOWN_VECTOR)
+		goto setnew;
+	/*
+	 * If the target CPU of the previous vector is online, then mark
+	 * the vector as move in progress and store it for cleanup when the
+	 * first interrupt on the new vector arrives. If the target CPU is
+	 * offline then the regular release mechanism via the cleanup
+	 * vector is not possible and the vector can be immediately freed
+	 * in the underlying matrix allocator.
+	 */
+	if (cpu_online(apicd->cpu)) {
 		apicd->move_in_progress = true;
 		apicd->prev_vector = apicd->vector;
 		apicd->prev_cpu = apicd->cpu;
 	} else {
-		apicd->prev_vector = 0;
+		irq_matrix_free(vector_matrix, apicd->cpu, apicd->vector,
+				managed);
 	}
 
+setnew:
 	apicd->vector = newvec;
 	apicd->cpu = newcpu;
 	BUG_ON(!IS_ERR_OR_NULL(per_cpu(vector_irq, newcpu)[newvec]));

[tip:x86/urgent] x86/apic/vector: Handle vector release on CPU unplug correctly

[tip-bot for Thomas Gleixner]

Commit-ID:  e84cf6aa501c58bf4bf451f1e425192ec090aed2
Gitweb:     https://git.kernel.org/tip/e84cf6aa501c58bf4bf451f1e425192ec090aed2
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 22 Feb 2018 12:08:06 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 23 Feb 2018 08:02:00 +0100

x86/apic/vector: Handle vector release on CPU unplug correctly

When a irq vector is replaced, then the previous vector is normally
released when the first interrupt happens on the new vector. If the target
CPU of the previous vector is already offline when the new vector is
installed, then the previous vector is silently discarded, which leads to
accounting issues causing suspend failures and other problems.

Adjust the logic so that the previous vector is freed in the underlying
matrix allocator to ensure that the accounting stays correct.

Fixes: 69cde0004a4b ("x86/vector: Use matrix allocator for vector assignment")
Reported-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Yuriy Vostrikov <delamonpansie@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180222112316.930791749@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/apic/vector.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 3cc471beb50b..bb6f7a2148d7 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -134,21 +134,40 @@ static void apic_update_vector(struct irq_data *irqd, unsigned int newvec,
 {
 	struct apic_chip_data *apicd = apic_chip_data(irqd);
 	struct irq_desc *desc = irq_data_to_desc(irqd);
+	bool managed = irqd_affinity_is_managed(irqd);
 
 	lockdep_assert_held(&vector_lock);
 
 	trace_vector_update(irqd->irq, newvec, newcpu, apicd->vector,
 			    apicd->cpu);
 
-	/* Setup the vector move, if required  */
-	if (apicd->vector && cpu_online(apicd->cpu)) {
+	/*
+	 * If there is no vector associated or if the associated vector is
+	 * the shutdown vector, which is associated to make PCI/MSI
+	 * shutdown mode work, then there is nothing to release. Clear out
+	 * prev_vector for this and the offlined target case.
+	 */
+	apicd->prev_vector = 0;
+	if (!apicd->vector || apicd->vector == MANAGED_IRQ_SHUTDOWN_VECTOR)
+		goto setnew;
+	/*
+	 * If the target CPU of the previous vector is online, then mark
+	 * the vector as move in progress and store it for cleanup when the
+	 * first interrupt on the new vector arrives. If the target CPU is
+	 * offline then the regular release mechanism via the cleanup
+	 * vector is not possible and the vector can be immediately freed
+	 * in the underlying matrix allocator.
+	 */
+	if (cpu_online(apicd->cpu)) {
 		apicd->move_in_progress = true;
 		apicd->prev_vector = apicd->vector;
 		apicd->prev_cpu = apicd->cpu;
 	} else {
-		apicd->prev_vector = 0;
+		irq_matrix_free(vector_matrix, apicd->cpu, apicd->vector,
+				managed);
 	}
 
+setnew:
 	apicd->vector = newvec;
 	apicd->cpu = newcpu;
 	BUG_ON(!IS_ERR_OR_NULL(per_cpu(vector_irq, newcpu)[newvec]));