[PATCH 3/6] drm/v3d: Replace a global spinlock with a per-queue spinlock
Maíra Canal
mcanal at igalia.com
Sat Jul 19 13:24:42 UTC 2025
Each V3D queue works independently and all the dependencies between the
jobs are handled through the DRM scheduler. Therefore, there is no need
to use one single lock for all queues. Using it, creates unnecessary
contention between different queues that can operate independently.
Replace the global spinlock with per-queue locks to improve parallelism
and reduce contention between different V3D queues (BIN, RENDER, TFU,
CSD). This allows independent queues to operate concurrently while
maintaining proper synchronization within each queue.
Signed-off-by: Maíra Canal <mcanal at igalia.com>
---
drivers/gpu/drm/v3d/v3d_drv.h | 8 ++------
drivers/gpu/drm/v3d/v3d_fence.c | 11 ++++++-----
drivers/gpu/drm/v3d/v3d_gem.c | 3 ++-
drivers/gpu/drm/v3d/v3d_irq.c | 6 +++---
drivers/gpu/drm/v3d/v3d_sched.c | 13 +++++++------
5 files changed, 20 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
index b5d7e58c3696a04b1824ecfe31e1962901746856..fb1a3d010fd5a61099f413629e9bfeeed3c45c59 100644
--- a/drivers/gpu/drm/v3d/v3d_drv.h
+++ b/drivers/gpu/drm/v3d/v3d_drv.h
@@ -61,6 +61,7 @@ struct v3d_queue_state {
/* Currently active job for this queue */
struct v3d_job *active_job;
+ spinlock_t queue_lock;
};
/* Performance monitor object. The perform lifetime is controlled by userspace
@@ -156,11 +157,6 @@ struct v3d_dev {
struct v3d_queue_state queue[V3D_MAX_QUEUES];
- /* Spinlock used to synchronize the overflow memory
- * management against bin job submission.
- */
- spinlock_t job_lock;
-
/* Used to track the active perfmon if any. */
struct v3d_perfmon *active_perfmon;
@@ -560,7 +556,7 @@ void v3d_get_stats(const struct v3d_stats *stats, u64 timestamp,
/* v3d_fence.c */
extern const struct dma_fence_ops v3d_fence_ops;
-struct dma_fence *v3d_fence_create(struct v3d_dev *v3d, enum v3d_queue queue);
+struct dma_fence *v3d_fence_create(struct v3d_dev *v3d, enum v3d_queue q);
/* v3d_gem.c */
int v3d_gem_init(struct drm_device *dev);
diff --git a/drivers/gpu/drm/v3d/v3d_fence.c b/drivers/gpu/drm/v3d/v3d_fence.c
index 89840ed212c06036e5b9ecef91852a490538ba89..8f8471adae34af7a444f5eeca4ef08d66ac1b7b5 100644
--- a/drivers/gpu/drm/v3d/v3d_fence.c
+++ b/drivers/gpu/drm/v3d/v3d_fence.c
@@ -3,8 +3,9 @@
#include "v3d_drv.h"
-struct dma_fence *v3d_fence_create(struct v3d_dev *v3d, enum v3d_queue queue)
+struct dma_fence *v3d_fence_create(struct v3d_dev *v3d, enum v3d_queue q)
{
+ struct v3d_queue_state *queue = &v3d->queue[q];
struct v3d_fence *fence;
fence = kzalloc(sizeof(*fence), GFP_KERNEL);
@@ -12,10 +13,10 @@ struct dma_fence *v3d_fence_create(struct v3d_dev *v3d, enum v3d_queue queue)
return ERR_PTR(-ENOMEM);
fence->dev = &v3d->drm;
- fence->queue = queue;
- fence->seqno = ++v3d->queue[queue].emit_seqno;
- dma_fence_init(&fence->base, &v3d_fence_ops, &v3d->job_lock,
- v3d->queue[queue].fence_context, fence->seqno);
+ fence->queue = q;
+ fence->seqno = ++queue->emit_seqno;
+ dma_fence_init(&fence->base, &v3d_fence_ops, &queue->queue_lock,
+ queue->fence_context, fence->seqno);
return &fence->base;
}
diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
index 7e0409a154497ecf500c4260e6aff0589b5932a1..c1593b5b2729eb6333197ef6a332b52ea567d474 100644
--- a/drivers/gpu/drm/v3d/v3d_gem.c
+++ b/drivers/gpu/drm/v3d/v3d_gem.c
@@ -269,10 +269,11 @@ v3d_gem_init(struct drm_device *dev)
queue->fence_context = dma_fence_context_alloc(1);
memset(&queue->stats, 0, sizeof(queue->stats));
seqcount_init(&queue->stats.lock);
+
+ spin_lock_init(&queue->queue_lock);
}
spin_lock_init(&v3d->mm_lock);
- spin_lock_init(&v3d->job_lock);
ret = drmm_mutex_init(dev, &v3d->bo_lock);
if (ret)
return ret;
diff --git a/drivers/gpu/drm/v3d/v3d_irq.c b/drivers/gpu/drm/v3d/v3d_irq.c
index e96c7fd65a147177993bbc45d573453974ac2e39..74c84e0bd1bb5aa01c8c8e0e24310dac872fc85c 100644
--- a/drivers/gpu/drm/v3d/v3d_irq.c
+++ b/drivers/gpu/drm/v3d/v3d_irq.c
@@ -62,17 +62,17 @@ v3d_overflow_mem_work(struct work_struct *work)
* bin job got scheduled, that's fine. We'll just give them
* some binner pool anyway.
*/
- spin_lock_irqsave(&v3d->job_lock, irqflags);
+ spin_lock_irqsave(&queue->queue_lock, irqflags);
bin_job = (struct v3d_bin_job *)queue->active_job;
if (!bin_job) {
- spin_unlock_irqrestore(&v3d->job_lock, irqflags);
+ spin_unlock_irqrestore(&queue->queue_lock, irqflags);
goto out;
}
drm_gem_object_get(obj);
list_add_tail(&bo->unref_head, &bin_job->render->unref_list);
- spin_unlock_irqrestore(&v3d->job_lock, irqflags);
+ spin_unlock_irqrestore(&queue->queue_lock, irqflags);
v3d_mmu_flush_all(v3d);
diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
index 4fbcd662b4c4e69d5680d77171ed85fb869959bd..85f6fdb470ae0270c0b4d421fb5e214a13c2e03a 100644
--- a/drivers/gpu/drm/v3d/v3d_sched.c
+++ b/drivers/gpu/drm/v3d/v3d_sched.c
@@ -222,27 +222,28 @@ static struct dma_fence *v3d_bin_job_run(struct drm_sched_job *sched_job)
{
struct v3d_bin_job *job = to_bin_job(sched_job);
struct v3d_dev *v3d = job->base.v3d;
+ struct v3d_queue_state *queue = &v3d->queue[V3D_BIN];
struct drm_device *dev = &v3d->drm;
struct dma_fence *fence;
unsigned long irqflags;
if (unlikely(job->base.base.s_fence->finished.error)) {
- spin_lock_irqsave(&v3d->job_lock, irqflags);
- v3d->queue[V3D_BIN].active_job = NULL;
- spin_unlock_irqrestore(&v3d->job_lock, irqflags);
+ spin_lock_irqsave(&queue->queue_lock, irqflags);
+ queue->active_job = NULL;
+ spin_unlock_irqrestore(&queue->queue_lock, irqflags);
return NULL;
}
/* Lock required around bin_job update vs
* v3d_overflow_mem_work().
*/
- spin_lock_irqsave(&v3d->job_lock, irqflags);
- v3d->queue[V3D_BIN].active_job = to_v3d_job(sched_job);
+ spin_lock_irqsave(&queue->queue_lock, irqflags);
+ queue->active_job = to_v3d_job(sched_job);
/* Clear out the overflow allocation, so we don't
* reuse the overflow attached to a previous job.
*/
V3D_CORE_WRITE(0, V3D_PTB_BPOS, 0);
- spin_unlock_irqrestore(&v3d->job_lock, irqflags);
+ spin_unlock_irqrestore(&queue->queue_lock, irqflags);
v3d_invalidate_caches(v3d);
--
2.50.0
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