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commit cbbfb0ae2ca979222297062647ced653682a6cc7
parent 42f52e1c59bdb78cad945b2dd34fa1f892239a39
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 23 Oct 2018 15:15:20 +0100

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

Diffstat:
March/x86/kernel/apic/vector.c | 9++++-----
Minclude/linux/irq.h | 3++-
Mkernel/irq/matrix.c | 82++++++++++++++++++++++++++++++++++++++++++++++++++-----------------------------
3 files changed, 58 insertions(+), 36 deletions(-)

diff --git 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 @@ -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 @@ -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; } /**