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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-10 11:33:08 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-10 11:33:08 -0700 |
commit | c44b59430393c38873fd933333d945f426857a59 (patch) | |
tree | 1af82d499fb4abb67487962f8d03f4088b367f37 /include | |
parent | 5ccd414080822d5257c3569f4aeca74f63f4a257 (diff) | |
parent | c8b0d7290657996a29f318b948d2397d30e70c36 (diff) | |
download | op-kernel-dev-c44b59430393c38873fd933333d945f426857a59.zip op-kernel-dev-c44b59430393c38873fd933333d945f426857a59.tar.gz |
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull virtio updates from Michael Tsirkin:
"Fixes, cleanups, performance
A bunch of changes to virtio, most affecting virtio net. Also ptr_ring
batched zeroing - first of batching enhancements that seems ready."
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
s390/virtio: change maintainership
tools/virtio: fix spelling mistake: "wakeus" -> "wakeups"
virtio_net: tidy a couple debug statements
ptr_ring: support testing different batching sizes
ringtest: support test specific parameters
ptr_ring: batch ring zeroing
virtio: virtio_driver doc
virtio_net: don't reset twice on XDP on/off
virtio_net: fix support for small rings
virtio_net: reduce alignment for buffers
virtio_net: rework mergeable buffer handling
virtio_net: allow specifying context for rx
virtio: allow extra context per descriptor
tools/virtio: fix build breakage
virtio: add context flag to find vqs
virtio: wrap find_vqs
ringtest: fix an assert statement
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/ptr_ring.h | 63 | ||||
-rw-r--r-- | include/linux/virtio.h | 13 | ||||
-rw-r--r-- | include/linux/virtio_config.h | 25 | ||||
-rw-r--r-- | include/linux/virtio_ring.h | 3 |
4 files changed, 93 insertions, 11 deletions
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h index 6c70444..6b2e0dd 100644 --- a/include/linux/ptr_ring.h +++ b/include/linux/ptr_ring.h @@ -34,11 +34,13 @@ struct ptr_ring { int producer ____cacheline_aligned_in_smp; spinlock_t producer_lock; - int consumer ____cacheline_aligned_in_smp; + int consumer_head ____cacheline_aligned_in_smp; /* next valid entry */ + int consumer_tail; /* next entry to invalidate */ spinlock_t consumer_lock; /* Shared consumer/producer data */ /* Read-only by both the producer and the consumer */ int size ____cacheline_aligned_in_smp; /* max entries in queue */ + int batch; /* number of entries to consume in a batch */ void **queue; }; @@ -170,7 +172,7 @@ static inline int ptr_ring_produce_bh(struct ptr_ring *r, void *ptr) static inline void *__ptr_ring_peek(struct ptr_ring *r) { if (likely(r->size)) - return r->queue[r->consumer]; + return r->queue[r->consumer_head]; return NULL; } @@ -231,9 +233,38 @@ static inline bool ptr_ring_empty_bh(struct ptr_ring *r) /* Must only be called after __ptr_ring_peek returned !NULL */ static inline void __ptr_ring_discard_one(struct ptr_ring *r) { - r->queue[r->consumer++] = NULL; - if (unlikely(r->consumer >= r->size)) - r->consumer = 0; + /* Fundamentally, what we want to do is update consumer + * index and zero out the entry so producer can reuse it. + * Doing it naively at each consume would be as simple as: + * r->queue[r->consumer++] = NULL; + * if (unlikely(r->consumer >= r->size)) + * r->consumer = 0; + * but that is suboptimal when the ring is full as producer is writing + * out new entries in the same cache line. Defer these updates until a + * batch of entries has been consumed. + */ + int head = r->consumer_head++; + + /* Once we have processed enough entries invalidate them in + * the ring all at once so producer can reuse their space in the ring. + * We also do this when we reach end of the ring - not mandatory + * but helps keep the implementation simple. + */ + if (unlikely(r->consumer_head - r->consumer_tail >= r->batch || + r->consumer_head >= r->size)) { + /* Zero out entries in the reverse order: this way we touch the + * cache line that producer might currently be reading the last; + * producer won't make progress and touch other cache lines + * besides the first one until we write out all entries. + */ + while (likely(head >= r->consumer_tail)) + r->queue[head--] = NULL; + r->consumer_tail = r->consumer_head; + } + if (unlikely(r->consumer_head >= r->size)) { + r->consumer_head = 0; + r->consumer_tail = 0; + } } static inline void *__ptr_ring_consume(struct ptr_ring *r) @@ -345,14 +376,27 @@ static inline void **__ptr_ring_init_queue_alloc(int size, gfp_t gfp) return kzalloc(ALIGN(size * sizeof(void *), SMP_CACHE_BYTES), gfp); } +static inline void __ptr_ring_set_size(struct ptr_ring *r, int size) +{ + r->size = size; + r->batch = SMP_CACHE_BYTES * 2 / sizeof(*(r->queue)); + /* We need to set batch at least to 1 to make logic + * in __ptr_ring_discard_one work correctly. + * Batching too much (because ring is small) would cause a lot of + * burstiness. Needs tuning, for now disable batching. + */ + if (r->batch > r->size / 2 || !r->batch) + r->batch = 1; +} + static inline int ptr_ring_init(struct ptr_ring *r, int size, gfp_t gfp) { r->queue = __ptr_ring_init_queue_alloc(size, gfp); if (!r->queue) return -ENOMEM; - r->size = size; - r->producer = r->consumer = 0; + __ptr_ring_set_size(r, size); + r->producer = r->consumer_head = r->consumer_tail = 0; spin_lock_init(&r->producer_lock); spin_lock_init(&r->consumer_lock); @@ -373,9 +417,10 @@ static inline void **__ptr_ring_swap_queue(struct ptr_ring *r, void **queue, else if (destroy) destroy(ptr); - r->size = size; + __ptr_ring_set_size(r, size); r->producer = producer; - r->consumer = 0; + r->consumer_head = 0; + r->consumer_tail = 0; old = r->queue; r->queue = queue; diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 7edfbdb..28b0e96 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -44,6 +44,12 @@ int virtqueue_add_inbuf(struct virtqueue *vq, void *data, gfp_t gfp); +int virtqueue_add_inbuf_ctx(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + void *ctx, + gfp_t gfp); + int virtqueue_add_sgs(struct virtqueue *vq, struct scatterlist *sgs[], unsigned int out_sgs, @@ -59,6 +65,9 @@ bool virtqueue_notify(struct virtqueue *vq); void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len); +void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len, + void **ctx); + void virtqueue_disable_cb(struct virtqueue *vq); bool virtqueue_enable_cb(struct virtqueue *vq); @@ -156,9 +165,13 @@ int virtio_device_restore(struct virtio_device *dev); * @feature_table_legacy: same as feature_table but when working in legacy mode. * @feature_table_size_legacy: number of entries in feature table legacy array. * @probe: the function to call when a device is found. Returns 0 or -errno. + * @scan: optional function to call after successful probe; intended + * for virtio-scsi to invoke a scan. * @remove: the function to call when a device is removed. * @config_changed: optional function to call when the device configuration * changes; may be called in interrupt context. + * @freeze: optional function to call during suspend/hibernation. + * @restore: optional function to call on resume. */ struct virtio_driver { struct device_driver driver; diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 8355bab..0133d8a 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -72,7 +72,8 @@ struct virtio_config_ops { void (*reset)(struct virtio_device *vdev); int (*find_vqs)(struct virtio_device *, unsigned nvqs, struct virtqueue *vqs[], vq_callback_t *callbacks[], - const char * const names[], struct irq_affinity *desc); + const char * const names[], const bool *ctx, + struct irq_affinity *desc); void (*del_vqs)(struct virtio_device *); u64 (*get_features)(struct virtio_device *vdev); int (*finalize_features)(struct virtio_device *vdev); @@ -173,12 +174,32 @@ struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, vq_callback_t *callbacks[] = { c }; const char *names[] = { n }; struct virtqueue *vq; - int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL); + int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL, + NULL); if (err < 0) return ERR_PTR(err); return vq; } +static inline +int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs, + struct virtqueue *vqs[], vq_callback_t *callbacks[], + const char * const names[], + struct irq_affinity *desc) +{ + return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc); +} + +static inline +int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs, + struct virtqueue *vqs[], vq_callback_t *callbacks[], + const char * const names[], const bool *ctx, + struct irq_affinity *desc) +{ + return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, + desc); +} + /** * virtio_device_ready - enable vq use in probe function * @vdev: the device diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h index e8d3693..270cfa8 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -71,6 +71,7 @@ struct virtqueue *vring_create_virtqueue(unsigned int index, struct virtio_device *vdev, bool weak_barriers, bool may_reduce_num, + bool ctx, bool (*notify)(struct virtqueue *vq), void (*callback)(struct virtqueue *vq), const char *name); @@ -80,6 +81,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, struct vring vring, struct virtio_device *vdev, bool weak_barriers, + bool ctx, bool (*notify)(struct virtqueue *), void (*callback)(struct virtqueue *), const char *name); @@ -93,6 +95,7 @@ struct virtqueue *vring_new_virtqueue(unsigned int index, unsigned int vring_align, struct virtio_device *vdev, bool weak_barriers, + bool ctx, void *pages, bool (*notify)(struct virtqueue *vq), void (*callback)(struct virtqueue *vq), |