path: root/kernel/irq/matrix.c
diff options
authorThomas Gleixner <tglx@linutronix.de>2018-02-22 12:08:05 +0100
committerThomas Gleixner <tglx@linutronix.de>2018-02-22 22:05:43 +0100
commit651ca2c00405a2ae3870cc0b4f15a182eb6fbe26 (patch)
treea720565264c2649da57435d29eb25f488929d65d /kernel/irq/matrix.c
parent894266466aa74a226e58e23975118ff6231dd2e4 (diff)
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
Diffstat (limited to 'kernel/irq/matrix.c')
1 files changed, 14 insertions, 9 deletions
diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c
index 5187dfe809ac..4c5770407031 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)
- 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;
@@ -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))
- if (cm->online) {
- clear_bit(bit, cm->alloc_map);
- cm->allocated--;
+ clear_bit(bit, cm->alloc_map);
+ cm->allocated--;
+ if (cm->online)
- if (!managed) {
- cm->available++;
+ if (!managed) {
+ cm->available++;
+ if (cm->online)
- }
trace_irq_matrix_free(bit, cpu, m, cm);