From 1818a63147fb034f185ce75554957a2eb9fb47d4 Mon Sep 17 00:00:00 2001 From: Maxime Coquelin Date: Tue, 23 Mar 2021 10:02:18 +0100 Subject: [PATCH] vhost: move dirty logging cache out of virtqueue This patch moves the per-virtqueue's dirty logging cache out of the virtqueue struct, by allocating it dynamically only when live-migration is enabled. It saves 8 cachelines in vhost_virtqueue struct. Signed-off-by: Maxime Coquelin Reviewed-by: Chenbo Xia Reviewed-by: David Marchand Tested-by: Balazs Nemeth --- lib/librte_vhost/vhost.c | 13 +++++++++++++ lib/librte_vhost/vhost.h | 2 +- lib/librte_vhost/vhost_user.c | 21 +++++++++++++++++++++ 3 files changed, 35 insertions(+), 1 deletion(-) diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c index 5a7c0c6cff..a8032e3ba1 100644 --- a/lib/librte_vhost/vhost.c +++ b/lib/librte_vhost/vhost.c @@ -145,6 +145,10 @@ __vhost_log_cache_sync(struct virtio_net *dev, struct vhost_virtqueue *vq) if (unlikely(!dev->log_base)) return; + /* No cache, nothing to sync */ + if (unlikely(!vq->log_cache)) + return; + rte_atomic_thread_fence(__ATOMIC_RELEASE); log_base = (unsigned long *)(uintptr_t)dev->log_base; @@ -177,6 +181,14 @@ vhost_log_cache_page(struct virtio_net *dev, struct vhost_virtqueue *vq, uint32_t offset = page / (sizeof(unsigned long) << 3); int i; + if (unlikely(!vq->log_cache)) { + /* No logging cache allocated, write dirty log map directly */ + rte_atomic_thread_fence(__ATOMIC_RELEASE); + vhost_log_page((uint8_t *)(uintptr_t)dev->log_base, page); + + return; + } + for (i = 0; i < vq->log_cache_nb_elem; i++) { struct log_cache_entry *elem = vq->log_cache + i; @@ -354,6 +366,7 @@ free_vq(struct virtio_net *dev, struct vhost_virtqueue *vq) } rte_free(vq->batch_copy_elems); rte_mempool_free(vq->iotlb_pool); + rte_free(vq->log_cache); rte_free(vq); } diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h index 717f410548..3a71dfeed9 100644 --- a/lib/librte_vhost/vhost.h +++ b/lib/librte_vhost/vhost.h @@ -183,7 +183,7 @@ struct vhost_virtqueue { bool used_wrap_counter; bool avail_wrap_counter; - struct log_cache_entry log_cache[VHOST_LOG_CACHE_NR]; + struct log_cache_entry *log_cache; uint16_t log_cache_nb_elem; rte_rwlock_t iotlb_lock; diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c index a60bb945ad..4d9e76e49e 100644 --- a/lib/librte_vhost/vhost_user.c +++ b/lib/librte_vhost/vhost_user.c @@ -2022,6 +2022,9 @@ vhost_user_get_vring_base(struct virtio_net **pdev, rte_free(vq->batch_copy_elems); vq->batch_copy_elems = NULL; + rte_free(vq->log_cache); + vq->log_cache = NULL; + msg->size = sizeof(msg->payload.state); msg->fd_num = 0; @@ -2121,6 +2124,7 @@ vhost_user_set_log_base(struct virtio_net **pdev, struct VhostUserMsg *msg, int fd = msg->fds[0]; uint64_t size, off; void *addr; + uint32_t i; if (validate_msg_fds(msg, 1) != 0) return RTE_VHOST_MSG_RESULT_ERR; @@ -2174,6 +2178,23 @@ vhost_user_set_log_base(struct virtio_net **pdev, struct VhostUserMsg *msg, dev->log_base = dev->log_addr + off; dev->log_size = size; + for (i = 0; i < dev->nr_vring; i++) { + struct vhost_virtqueue *vq = dev->virtqueue[i]; + + rte_free(vq->log_cache); + vq->log_cache = NULL; + vq->log_cache_nb_elem = 0; + vq->log_cache = rte_zmalloc("vq log cache", + sizeof(struct log_cache_entry) * VHOST_LOG_CACHE_NR, + 0); + /* + * If log cache alloc fail, don't fail migration, but no + * caching will be done, which will impact performance + */ + if (!vq->log_cache) + VHOST_LOG_CONFIG(ERR, "Failed to allocate VQ logging cache\n"); + } + /* * The spec is not clear about it (yet), but QEMU doesn't expect * any payload in the reply. -- 2.20.1