From 1b1f42d8fde4fef1ed7873bf5aa91755f8c3de35 Mon Sep 17 00:00:00 2001 From: Lucas Stach Date: Wed, 6 Dec 2017 17:49:39 +0100 Subject: drm: move amd_gpu_scheduler into common location MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This moves and renames the AMDGPU scheduler to a common location in DRM in order to facilitate re-use by other drivers. This is mostly a straight forward rename with no code changes. One notable exception is the function to_drm_sched_fence(), which is no longer a inline header function to avoid the need to export the drm_sched_fence_ops_scheduled and drm_sched_fence_ops_finished structures. Reviewed-by: Chunming Zhou Tested-by: Dieter Nützel Acked-by: Alex Deucher Signed-off-by: Lucas Stach Signed-off-by: Alex Deucher --- include/drm/spsc_queue.h | 122 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100644 include/drm/spsc_queue.h (limited to 'include/drm/spsc_queue.h') diff --git a/include/drm/spsc_queue.h b/include/drm/spsc_queue.h new file mode 100644 index 000000000000..125f096c88cb --- /dev/null +++ b/include/drm/spsc_queue.h @@ -0,0 +1,122 @@ +/* + * Copyright 2017 Advanced Micro Devices, Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + * + */ + +#ifndef DRM_SCHEDULER_SPSC_QUEUE_H_ +#define DRM_SCHEDULER_SPSC_QUEUE_H_ + +#include +#include + +/** SPSC lockless queue */ + +struct spsc_node { + + /* Stores spsc_node* */ + struct spsc_node *next; +}; + +struct spsc_queue { + + struct spsc_node *head; + + /* atomic pointer to struct spsc_node* */ + atomic_long_t tail; + + atomic_t job_count; +}; + +static inline void spsc_queue_init(struct spsc_queue *queue) +{ + queue->head = NULL; + atomic_long_set(&queue->tail, (long)&queue->head); + atomic_set(&queue->job_count, 0); +} + +static inline struct spsc_node *spsc_queue_peek(struct spsc_queue *queue) +{ + return queue->head; +} + +static inline int spsc_queue_count(struct spsc_queue *queue) +{ + return atomic_read(&queue->job_count); +} + +static inline bool spsc_queue_push(struct spsc_queue *queue, struct spsc_node *node) +{ + struct spsc_node **tail; + + node->next = NULL; + + preempt_disable(); + + tail = (struct spsc_node **)atomic_long_xchg(&queue->tail, (long)&node->next); + WRITE_ONCE(*tail, node); + atomic_inc(&queue->job_count); + + /* + * In case of first element verify new node will be visible to the consumer + * thread when we ping the kernel thread that there is new work to do. + */ + smp_wmb(); + + preempt_enable(); + + return tail == &queue->head; +} + + +static inline struct spsc_node *spsc_queue_pop(struct spsc_queue *queue) +{ + struct spsc_node *next, *node; + + /* Verify reading from memory and not the cache */ + smp_rmb(); + + node = READ_ONCE(queue->head); + + if (!node) + return NULL; + + next = READ_ONCE(node->next); + WRITE_ONCE(queue->head, next); + + if (unlikely(!next)) { + /* slowpath for the last element in the queue */ + + if (atomic_long_cmpxchg(&queue->tail, + (long)&node->next, (long) &queue->head) != (long)&node->next) { + /* Updating tail failed wait for new next to appear */ + do { + smp_rmb(); + } while (unlikely(!(queue->head = READ_ONCE(node->next)))); + } + } + + atomic_dec(&queue->job_count); + return node; +} + + + +#endif /* DRM_SCHEDULER_SPSC_QUEUE_H_ */ -- cgit v1.2.3