On Fri, Sep 03, 2021 at 11:47:52AM -0700, Rob Clark wrote:
From: Rob Clark robdclark@chromium.org
Add a way to hint to the fence signaler of an upcoming deadline, such as vblank, which the fence waiter would prefer not to miss. This is to aid the fence signaler in making power management decisions, like boosting frequency as the deadline approaches and awareness of missing deadlines so that can be factored in to the frequency scaling.
v2: Drop dma_fence::deadline and related logic to filter duplicate deadlines, to avoid increasing dma_fence size. The fence-context implementation will need similar logic to track deadlines of all the fences on the same timeline. [ckoenig]
Signed-off-by: Rob Clark robdclark@chromium.org Reviewed-by: Christian König christian.koenig@amd.com Signed-off-by: Rob Clark robdclark@chromium.org
drivers/dma-buf/dma-fence.c | 20 ++++++++++++++++++++ include/linux/dma-fence.h | 16 ++++++++++++++++ 2 files changed, 36 insertions(+)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index ce0f5eff575d..1f444863b94d 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -910,6 +910,26 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count, } EXPORT_SYMBOL(dma_fence_wait_any_timeout);
+/**
- dma_fence_set_deadline - set desired fence-wait deadline
- @fence: the fence that is to be waited on
- @deadline: the time by which the waiter hopes for the fence to be
signaled
- Inform the fence signaler of an upcoming deadline, such as vblank, by
- which point the waiter would prefer the fence to be signaled by. This
- is intended to give feedback to the fence signaler to aid in power
- management decisions, such as boosting GPU frequency if a periodic
- vblank deadline is approaching.
- */
+void dma_fence_set_deadline(struct dma_fence *fence, ktime_t deadline) +{
- if (fence->ops->set_deadline && !dma_fence_is_signaled(fence))
fence->ops->set_deadline(fence, deadline);+} +EXPORT_SYMBOL(dma_fence_set_deadline);
/**
- dma_fence_init - Initialize a custom fence.
- @fence: the fence to initialize
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 6ffb4b2c6371..9c809f0d5d0a 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -99,6 +99,7 @@ enum dma_fence_flag_bits { DMA_FENCE_FLAG_SIGNALED_BIT, DMA_FENCE_FLAG_TIMESTAMP_BIT, DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
- DMA_FENCE_FLAG_HAS_DEADLINE_BIT, DMA_FENCE_FLAG_USER_BITS, /* must always be last member */
};
@@ -261,6 +262,19 @@ struct dma_fence_ops { */ void (*timeline_value_str)(struct dma_fence *fence, char *str, int size);
- /**
* @set_deadline:** Callback to allow a fence waiter to inform the fence signaler of an* upcoming deadline, such as vblank, by which point the waiter would* prefer the fence to be signaled by. This is intended to give feedback* to the fence signaler to aid in power management decisions, such as* boosting GPU frequency.
Please add here that this callback is called without &dma_fence.lock held, and that locking is up to callers if they have some state to manage.
I realized that while scratching some heads over your later patches. -Daniel
** This callback is optional.*/- void (*set_deadline)(struct dma_fence *fence, ktime_t deadline);
};
void dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops, @@ -586,6 +600,8 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) return ret < 0 ? ret : 0; }
+void dma_fence_set_deadline(struct dma_fence *fence, ktime_t deadline);
struct dma_fence *dma_fence_get_stub(void); struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); -- 2.31.1