From f7fa7aeeecb7a9abdd5f5d069a71ffb3e99a2a07 Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Tue, 14 Apr 2015 10:30:10 +0800 Subject: [PATCH] x86/irq: Avoid memory allocation in __assign_irq_vector() Function __assign_irq_vector() is protected by vector_lock, so use a global temporary cpu_mask to avoid allocating/freeing cpu_mask. Signed-off-by: Jiang Liu Cc: Konrad Rzeszutek Wilk Cc: David Cohen Cc: Sander Eikelenboom Cc: David Vrabel Cc: Tony Luck Cc: Joerg Roedel Cc: Greg Kroah-Hartman Cc: Bjorn Helgaas Cc: Benjamin Herrenschmidt Cc: Rafael J. Wysocki Cc: Randy Dunlap Cc: Yinghai Lu Cc: Borislav Petkov Cc: Dimitri Sivanich Link: http://lkml.kernel.org/r/1428978610-28986-34-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner --- arch/x86/kernel/apic/vector.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c index ad786f8a7cc7..1c7dd42b98c1 100644 --- a/arch/x86/kernel/apic/vector.c +++ b/arch/x86/kernel/apic/vector.c @@ -30,6 +30,7 @@ struct apic_chip_data { struct irq_domain *x86_vector_domain; static DEFINE_RAW_SPINLOCK(vector_lock); +static cpumask_var_t vector_cpumask; static struct irq_chip lapic_controller; #ifdef CONFIG_X86_IO_APIC static struct apic_chip_data *legacy_irq_data[NR_IRQS_LEGACY]; @@ -116,14 +117,10 @@ static int __assign_irq_vector(int irq, struct apic_chip_data *d, static int current_vector = FIRST_EXTERNAL_VECTOR + VECTOR_OFFSET_START; static int current_offset = VECTOR_OFFSET_START % 16; int cpu, err; - cpumask_var_t tmp_mask; if (d->move_in_progress) return -EBUSY; - if (!alloc_cpumask_var(&tmp_mask, GFP_ATOMIC)) - return -ENOMEM; - /* Only try and allocate irqs on cpus that are present */ err = -ENOSPC; cpumask_clear(d->old_domain); @@ -131,21 +128,22 @@ static int __assign_irq_vector(int irq, struct apic_chip_data *d, while (cpu < nr_cpu_ids) { int new_cpu, vector, offset; - apic->vector_allocation_domain(cpu, tmp_mask, mask); + apic->vector_allocation_domain(cpu, vector_cpumask, mask); - if (cpumask_subset(tmp_mask, d->domain)) { + if (cpumask_subset(vector_cpumask, d->domain)) { err = 0; - if (cpumask_equal(tmp_mask, d->domain)) + if (cpumask_equal(vector_cpumask, d->domain)) break; /* * New cpumask using the vector is a proper subset of * the current in use mask. So cleanup the vector * allocation for the members that are not used anymore. */ - cpumask_andnot(d->old_domain, d->domain, tmp_mask); + cpumask_andnot(d->old_domain, d->domain, + vector_cpumask); d->move_in_progress = cpumask_intersects(d->old_domain, cpu_online_mask); - cpumask_and(d->domain, d->domain, tmp_mask); + cpumask_and(d->domain, d->domain, vector_cpumask); break; } @@ -159,16 +157,18 @@ next: } if (unlikely(current_vector == vector)) { - cpumask_or(d->old_domain, d->old_domain, tmp_mask); - cpumask_andnot(tmp_mask, mask, d->old_domain); - cpu = cpumask_first_and(tmp_mask, cpu_online_mask); + cpumask_or(d->old_domain, d->old_domain, + vector_cpumask); + cpumask_andnot(vector_cpumask, mask, d->old_domain); + cpu = cpumask_first_and(vector_cpumask, + cpu_online_mask); continue; } if (test_bit(vector, used_vectors)) goto next; - for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask) { + for_each_cpu_and(new_cpu, vector_cpumask, cpu_online_mask) { if (per_cpu(vector_irq, new_cpu)[vector] > VECTOR_UNDEFINED) goto next; @@ -181,14 +181,13 @@ next: d->move_in_progress = cpumask_intersects(d->old_domain, cpu_online_mask); } - for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask) + for_each_cpu_and(new_cpu, vector_cpumask, cpu_online_mask) per_cpu(vector_irq, new_cpu)[vector] = irq; d->cfg.vector = vector; - cpumask_copy(d->domain, tmp_mask); + cpumask_copy(d->domain, vector_cpumask); err = 0; break; } - free_cpumask_var(tmp_mask); if (!err) { /* cache destination APIC IDs into cfg->dest_apicid */ @@ -397,6 +396,8 @@ int __init arch_early_irq_init(void) arch_init_msi_domain(x86_vector_domain); arch_init_htirq_domain(x86_vector_domain); + BUG_ON(!alloc_cpumask_var(&vector_cpumask, GFP_KERNEL)); + return arch_early_ioapic_init(); } -- 2.39.2