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authorLinus Torvalds <torvalds@linux-foundation.org>2018-10-23 17:15:20 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-23 17:15:20 +0300
commitcbbfb0ae2ca979222297062647ced653682a6cc7 (patch)
tree15744f08287f776eb53c3fd1c97817f0e320875a
parent42f52e1c59bdb78cad945b2dd34fa1f892239a39 (diff)
parent76f99ae5b54d48430d1f0c5512a84da0ff9761e0 (diff)
downloadlinux-cbbfb0ae2ca979222297062647ced653682a6cc7.tar.xz
Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 apic updates from Ingo Molnar: "Improve the spreading of managed IRQs at allocation time" * 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irq/matrix: Spread managed interrupts on allocation irq/matrix: Split out the CPU selection code into a helper
-rw-r--r--arch/x86/kernel/apic/vector.c9
-rw-r--r--include/linux/irq.h3
-rw-r--r--kernel/irq/matrix.c82
3 files changed, 58 insertions, 36 deletions
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 7654febd5102..652e7ffa9b9d 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -313,14 +313,13 @@ assign_managed_vector(struct irq_data *irqd, const struct cpumask *dest)
struct apic_chip_data *apicd = apic_chip_data(irqd);
int vector, cpu;
- cpumask_and(vector_searchmask, vector_searchmask, affmsk);
- cpu = cpumask_first(vector_searchmask);
- if (cpu >= nr_cpu_ids)
- return -EINVAL;
+ cpumask_and(vector_searchmask, dest, affmsk);
+
/* set_affinity might call here for nothing */
if (apicd->vector && cpumask_test_cpu(apicd->cpu, vector_searchmask))
return 0;
- vector = irq_matrix_alloc_managed(vector_matrix, cpu);
+ vector = irq_matrix_alloc_managed(vector_matrix, vector_searchmask,
+ &cpu);
trace_vector_alloc_managed(irqd->irq, vector, vector);
if (vector < 0)
return vector;
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 201de12a9957..c9bffda04a45 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -1151,7 +1151,8 @@ void irq_matrix_offline(struct irq_matrix *m);
void irq_matrix_assign_system(struct irq_matrix *m, unsigned int bit, bool replace);
int irq_matrix_reserve_managed(struct irq_matrix *m, const struct cpumask *msk);
void irq_matrix_remove_managed(struct irq_matrix *m, const struct cpumask *msk);
-int irq_matrix_alloc_managed(struct irq_matrix *m, unsigned int cpu);
+int irq_matrix_alloc_managed(struct irq_matrix *m, const struct cpumask *msk,
+ unsigned int *mapped_cpu);
void irq_matrix_reserve(struct irq_matrix *m);
void irq_matrix_remove_reserved(struct irq_matrix *m);
int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c
index 5092494bf261..6e6d467f3dec 100644
--- a/kernel/irq/matrix.c
+++ b/kernel/irq/matrix.c
@@ -124,6 +124,27 @@ static unsigned int matrix_alloc_area(struct irq_matrix *m, struct cpumap *cm,
return area;
}
+/* Find the best CPU which has the lowest vector allocation count */
+static unsigned int matrix_find_best_cpu(struct irq_matrix *m,
+ const struct cpumask *msk)
+{
+ unsigned int cpu, best_cpu, maxavl = 0;
+ struct cpumap *cm;
+
+ best_cpu = UINT_MAX;
+
+ for_each_cpu(cpu, msk) {
+ cm = per_cpu_ptr(m->maps, cpu);
+
+ if (!cm->online || cm->available <= maxavl)
+ continue;
+
+ best_cpu = cpu;
+ maxavl = cm->available;
+ }
+ return best_cpu;
+}
+
/**
* irq_matrix_assign_system - Assign system wide entry in the matrix
* @m: Matrix pointer
@@ -239,11 +260,21 @@ void irq_matrix_remove_managed(struct irq_matrix *m, const struct cpumask *msk)
* @m: Matrix pointer
* @cpu: On which CPU the interrupt should be allocated
*/
-int irq_matrix_alloc_managed(struct irq_matrix *m, unsigned int cpu)
+int irq_matrix_alloc_managed(struct irq_matrix *m, const struct cpumask *msk,
+ unsigned int *mapped_cpu)
{
- struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
- unsigned int bit, end = m->alloc_end;
+ unsigned int bit, cpu, end = m->alloc_end;
+ struct cpumap *cm;
+
+ if (cpumask_empty(msk))
+ return -EINVAL;
+
+ cpu = matrix_find_best_cpu(m, msk);
+ if (cpu == UINT_MAX)
+ return -ENOSPC;
+ cm = per_cpu_ptr(m->maps, cpu);
+ end = m->alloc_end;
/* Get managed bit which are not allocated */
bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
bit = find_first_bit(m->scratch_map, end);
@@ -252,6 +283,7 @@ int irq_matrix_alloc_managed(struct irq_matrix *m, unsigned int cpu)
set_bit(bit, cm->alloc_map);
cm->allocated++;
m->total_allocated++;
+ *mapped_cpu = cpu;
trace_irq_matrix_alloc_managed(bit, cpu, m, cm);
return bit;
}
@@ -322,37 +354,27 @@ void irq_matrix_remove_reserved(struct irq_matrix *m)
int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
bool reserved, unsigned int *mapped_cpu)
{
- unsigned int cpu, best_cpu, maxavl = 0;
+ unsigned int cpu, bit;
struct cpumap *cm;
- unsigned int bit;
-
- best_cpu = UINT_MAX;
- for_each_cpu(cpu, msk) {
- cm = per_cpu_ptr(m->maps, cpu);
- if (!cm->online || cm->available <= maxavl)
- continue;
+ cpu = matrix_find_best_cpu(m, msk);
+ if (cpu == UINT_MAX)
+ return -ENOSPC;
- best_cpu = cpu;
- maxavl = cm->available;
- }
+ cm = per_cpu_ptr(m->maps, cpu);
+ bit = matrix_alloc_area(m, cm, 1, false);
+ if (bit >= m->alloc_end)
+ return -ENOSPC;
+ cm->allocated++;
+ cm->available--;
+ m->total_allocated++;
+ m->global_available--;
+ if (reserved)
+ m->global_reserved--;
+ *mapped_cpu = cpu;
+ trace_irq_matrix_alloc(bit, cpu, m, cm);
+ return bit;
- if (maxavl) {
- cm = per_cpu_ptr(m->maps, best_cpu);
- bit = matrix_alloc_area(m, cm, 1, false);
- if (bit < m->alloc_end) {
- cm->allocated++;
- cm->available--;
- m->total_allocated++;
- m->global_available--;
- if (reserved)
- m->global_reserved--;
- *mapped_cpu = best_cpu;
- trace_irq_matrix_alloc(bit, best_cpu, m, cm);
- return bit;
- }
- }
- return -ENOSPC;
}
/**