| Message ID | 20201222135658.53916-3-maxime.coquelin@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Maxime Coquelin |
| Headers | show |
| Series | vhost: make virtqueue cache-friendly | expand |
| Context | Check | Description |
|---|---|---|
| ci/checkpatch | warning | coding style issues |
Hi Maxime, > -----Original Message----- > From: Maxime Coquelin <maxime.coquelin@redhat.com> > Sent: Tuesday, December 22, 2020 9:57 PM > To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; amorenoz@redhat.com > Cc: Maxime Coquelin <maxime.coquelin@redhat.com> > Subject: [PATCH 2/3] vhost: move dirty logging cache out of the 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 <maxime.coquelin@redhat.com> > --- > lib/librte_vhost/vhost.c | 12 ++++++++++++ > lib/librte_vhost/vhost.h | 2 +- > lib/librte_vhost/vhost_user.c | 25 +++++++++++++++++++++++++ > 3 files changed, 38 insertions(+), 1 deletion(-) > > diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c > index 4e5df862aa..ec6459b2d1 100644 > --- a/lib/librte_vhost/vhost.c > +++ b/lib/librte_vhost/vhost.c > @@ -144,6 +144,10 @@ __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_smp_wmb(); > > log_base = (unsigned long *)(uintptr_t)dev->log_base; > @@ -176,6 +180,14 @@ 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_smp_wmb(); > + 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; > > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h > index d132e4ae54..e2f14034b4 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 45c8ac09da..7ac3963a07 100644 > --- a/lib/librte_vhost/vhost_user.c > +++ b/lib/librte_vhost/vhost_user.c > @@ -1978,6 +1978,11 @@ vhost_user_get_vring_base(struct virtio_net **pdev, > rte_free(vq->batch_copy_elems); > vq->batch_copy_elems = NULL; > > + if (vq->log_cache) { > + rte_free(vq->log_cache); > + vq->log_cache = NULL; > + } > + I think we'd better check and free the log cache in function free_vq() too? It is possible that during migration, vhost destroys, right? Thanks, Chenbo > msg->size = sizeof(msg->payload.state); > msg->fd_num = 0; > > @@ -2077,6 +2082,7 @@ 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; > @@ -2130,6 +2136,25 @@ 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]; > + > + if (vq->log_cache) { > + 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. > -- > 2.29.2
diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c index 4e5df862aa..ec6459b2d1 100644 --- a/lib/librte_vhost/vhost.c +++ b/lib/librte_vhost/vhost.c @@ -144,6 +144,10 @@ __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_smp_wmb(); log_base = (unsigned long *)(uintptr_t)dev->log_base; @@ -176,6 +180,14 @@ 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_smp_wmb(); + 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; diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h index d132e4ae54..e2f14034b4 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 45c8ac09da..7ac3963a07 100644 --- a/lib/librte_vhost/vhost_user.c +++ b/lib/librte_vhost/vhost_user.c @@ -1978,6 +1978,11 @@ vhost_user_get_vring_base(struct virtio_net **pdev, rte_free(vq->batch_copy_elems); vq->batch_copy_elems = NULL; + if (vq->log_cache) { + rte_free(vq->log_cache); + vq->log_cache = NULL; + } + msg->size = sizeof(msg->payload.state); msg->fd_num = 0; @@ -2077,6 +2082,7 @@ 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; @@ -2130,6 +2136,25 @@ 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]; + + if (vq->log_cache) { + 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.
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 <maxime.coquelin@redhat.com> --- lib/librte_vhost/vhost.c | 12 ++++++++++++ lib/librte_vhost/vhost.h | 2 +- lib/librte_vhost/vhost_user.c | 25 +++++++++++++++++++++++++ 3 files changed, 38 insertions(+), 1 deletion(-)