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| author | Bhaktipriya Shridhar <bhaktipriya96@gmail.com> | 2016-08-30 23:29:51 +0530 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-09-07 19:34:28 +0200 |
| commit | 3706feacd007c89f49bdb20c5c1dd17c8badfc43 (patch) | |
| tree | a719e04c4f1871e8271eb3d2091cef727a3288db /virt/kvm/eventfd.c | |
| parent | f15a75eedc18e1fece8e01f1a6f7d135e61b0750 (diff) | |
| download | linux-3706feacd007c89f49bdb20c5c1dd17c8badfc43.tar.bz2 | |
KVM: Remove deprecated create_singlethread_workqueue
The workqueue "irqfd_cleanup_wq" queues a single work item
&irqfd->shutdown and hence doesn't require ordering. It is a host-wide
workqueue for issuing deferred shutdown requests aggregated from all
vm* instances. It is not being used on a memory reclaim path.
Hence, it has been converted to use system_wq.
The work item has been flushed in kvm_irqfd_release().
The workqueue "wqueue" queues a single work item &timer->expired
and hence doesn't require ordering. Also, it is not being used on
a memory reclaim path. Hence, it has been converted to use system_wq.
System workqueues have been able to handle high level of concurrency
for a long time now and hence it's not required to have a singlethreaded
workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
created with create_singlethread_workqueue(), system_wq allows multiple
work items to overlap executions even on the same CPU; however, a
per-cpu workqueue doesn't have any CPU locality or global ordering
guarantee unless the target CPU is explicitly specified and thus the
increase of local concurrency shouldn't make any difference.
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt/kvm/eventfd.c')
| -rw-r--r-- | virt/kvm/eventfd.c | 22 |
1 files changed, 3 insertions, 19 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index e469b6012471..f397e9b20370 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -42,7 +42,6 @@ #ifdef CONFIG_HAVE_KVM_IRQFD -static struct workqueue_struct *irqfd_cleanup_wq; static void irqfd_inject(struct work_struct *work) @@ -168,7 +167,7 @@ irqfd_deactivate(struct kvm_kernel_irqfd *irqfd) list_del_init(&irqfd->list); - queue_work(irqfd_cleanup_wq, &irqfd->shutdown); + schedule_work(&irqfd->shutdown); } int __attribute__((weak)) kvm_arch_set_irq_inatomic( @@ -555,7 +554,7 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args) * so that we guarantee there will not be any more interrupts on this * gsi once this deassign function returns. */ - flush_workqueue(irqfd_cleanup_wq); + flush_work(&irqfd->shutdown); return 0; } @@ -592,7 +591,7 @@ kvm_irqfd_release(struct kvm *kvm) * Block until we know all outstanding shutdown jobs have completed * since we do not take a kvm* reference. */ - flush_workqueue(irqfd_cleanup_wq); + flush_work(&irqfd->shutdown); } @@ -622,23 +621,8 @@ void kvm_irq_routing_update(struct kvm *kvm) spin_unlock_irq(&kvm->irqfds.lock); } -/* - * create a host-wide workqueue for issuing deferred shutdown requests - * aggregated from all vm* instances. We need our own isolated single-thread - * queue to prevent deadlock against flushing the normal work-queue. - */ -int kvm_irqfd_init(void) -{ - irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup"); - if (!irqfd_cleanup_wq) - return -ENOMEM; - - return 0; -} - void kvm_irqfd_exit(void) { - destroy_workqueue(irqfd_cleanup_wq); } #endif |