virtio-blk has been converted to use the threadpool. All the threading code has been removed, which left only simple callback handling code.
New threadpool job types are created within VIRTIO_PCI_QUEUE_PFN for every queue (just one in the case of virtio-blk). The module signals for work after receiving VIRTIO_PCI_QUEUE_NOTIFY and expects the threadpool to call virtio_blk_do_io to handle the I/O. It is possible that the module will signal work several times while virtio_blk_do_io is already working, but there is no need to handle multithreading there since the threadpool will call each job in linear and not in parallel. Signed-off-by: Sasha Levin <[email protected]> --- tools/kvm/virtio-blk.c | 86 +++++++----------------------------------------- 1 files changed, 12 insertions(+), 74 deletions(-) diff --git a/tools/kvm/virtio-blk.c b/tools/kvm/virtio-blk.c index 3516b1c..3feabd0 100644 --- a/tools/kvm/virtio-blk.c +++ b/tools/kvm/virtio-blk.c @@ -9,6 +9,7 @@ #include "kvm/util.h" #include "kvm/kvm.h" #include "kvm/pci.h" +#include "kvm/threadpool.h" #include <linux/virtio_ring.h> #include <linux/virtio_blk.h> @@ -31,15 +32,13 @@ struct blk_device { uint32_t guest_features; uint16_t config_vector; uint8_t status; - pthread_t io_thread; - pthread_mutex_t io_mutex; - pthread_cond_t io_cond; /* virtio queue */ uint16_t queue_selector; - uint64_t virtio_blk_queue_set_flags; struct virt_queue vqs[NUM_VIRT_QUEUES]; + + void *jobs[NUM_VIRT_QUEUES]; }; #define DISK_SEG_MAX 126 @@ -57,9 +56,6 @@ static struct blk_device blk_device = { * same applies to VIRTIO_BLK_F_BLK_SIZE */ .host_features = (1UL << VIRTIO_BLK_F_SEG_MAX), - - .io_mutex = PTHREAD_MUTEX_INITIALIZER, - .io_cond = PTHREAD_COND_INITIALIZER }; static bool virtio_blk_pci_io_device_specific_in(void *data, unsigned long offset, int size, uint32_t count) @@ -156,73 +152,14 @@ static bool virtio_blk_do_io_request(struct kvm *self, struct virt_queue *queue) return true; } - - -static int virtio_blk_get_selected_queue(struct blk_device *dev) -{ - int i; - - for (i = 0 ; i < NUM_VIRT_QUEUES ; i++) { - if (dev->virtio_blk_queue_set_flags & (1 << i)) { - dev->virtio_blk_queue_set_flags &= ~(1 << i); - return i; - } - } - - return -1; -} - -static void virtio_blk_do_io(struct kvm *kvm, struct blk_device *dev) +static void virtio_blk_do_io(struct kvm *kvm, void *param) { - for (;;) { - struct virt_queue *vq; - int queue_index; - - mutex_lock(&dev->io_mutex); - queue_index = virtio_blk_get_selected_queue(dev); - mutex_unlock(&dev->io_mutex); - - if (queue_index < 0) - break; + struct virt_queue *vq = param; - vq = &dev->vqs[queue_index]; + while (virt_queue__available(vq)) + virtio_blk_do_io_request(kvm, vq); - while (virt_queue__available(vq)) - virtio_blk_do_io_request(kvm, vq); - - kvm__irq_line(kvm, VIRTIO_BLK_IRQ, 1); - } -} - -static void *virtio_blk_io_thread(void *ptr) -{ - struct kvm *self = ptr; - - for (;;) { - int ret; - - mutex_lock(&blk_device.io_mutex); - ret = pthread_cond_wait(&blk_device.io_cond, &blk_device.io_mutex); - mutex_unlock(&blk_device.io_mutex); - - if (ret != 0) - break; - - virtio_blk_do_io(self, &blk_device); - } - - return NULL; -} - -static void virtio_blk_handle_callback(struct blk_device *dev, uint16_t queue_index) -{ - mutex_lock(&dev->io_mutex); - - dev->virtio_blk_queue_set_flags |= (1 << queue_index); - - mutex_unlock(&dev->io_mutex); - - pthread_cond_signal(&dev->io_cond); + kvm__irq_line(kvm, VIRTIO_BLK_IRQ, 1); } static bool virtio_blk_pci_io_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count) @@ -250,6 +187,9 @@ static bool virtio_blk_pci_io_out(struct kvm *self, uint16_t port, void *data, i vring_init(&queue->vring, VIRTIO_BLK_QUEUE_SIZE, p, 4096); + blk_device.jobs[blk_device.queue_selector] = + thread_pool__add_jobtype(self, virtio_blk_do_io, queue); + break; } case VIRTIO_PCI_QUEUE_SEL: @@ -258,7 +198,7 @@ static bool virtio_blk_pci_io_out(struct kvm *self, uint16_t port, void *data, i case VIRTIO_PCI_QUEUE_NOTIFY: { uint16_t queue_index; queue_index = ioport__read16(data); - virtio_blk_handle_callback(&blk_device, queue_index); + thread_pool__signal_work(blk_device.jobs[queue_index]); break; } case VIRTIO_PCI_STATUS: @@ -308,8 +248,6 @@ void virtio_blk__init(struct kvm *self) if (!self->disk_image) return; - pthread_create(&blk_device.io_thread, NULL, virtio_blk_io_thread, self); - blk_device.blk_config.capacity = self->disk_image->size / SECTOR_SIZE; pci__register(&virtio_blk_pci_device, PCI_VIRTIO_BLK_DEVNUM); -- 1.7.5.rc3 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
