Am 31.01.2018 um 00:21 schrieb Felix Kuehling:
On 2018-01-30 10:35 AM, Christian König wrote:
Am 30.01.2018 um 16:28 schrieb Kasiviswanathan, Harish:
[+Harish, forgot to acknowledge him in the commit description, will
fix
that in v2]
Harish, please see Christian's question below in amd_kfd_fence_signal.
Did I understand this correctly?
[HK]: Yes the lifetime of eviction fences is tied to the lifetime of
the process associated with it. When the process terminates the fence
is signaled and released. For all the BOs that belong to this process
the eviction should be detached from it when the BO is released.
However, this eviction fence could be still attached to shared BOs.
So signaling it frees those BOs.
On 2018-01-29 08:43 AM, Christian König wrote:
Hi Felix & Harish,
maybe explain why I found that odd: dma_fence_add_callback() sets the
DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT flag before adding the callback.
So the flag should always be set when there are callbacks.
Did I miss anything?
I don't think we add any callbacks to our eviction fences.
[HK] Setting DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT is not required. It was
my oversight. Since, dma_fence_signal() function called cb_list
functions only if DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT is set, I thought
it was safe to set it. However, the cb_list would be empty if no
callbacks are added. So setting DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT is
redundant.
Ok in this case let's just remove that and also use the
dma_fence_signal() function (not the _locked variant) for signaling
the DMA fence.
Sure. Though it makes me wonder why we need to signal the fence at all.
This is when the reference count of the fence is 0. Doesn't that imply
that no one is left waiting for the fence?
Good point as well, yeah when the fences reference count becomes zero
there is no point in signaling it.
So the whole function can be removed.
Regards,
Christian.
Regards,
Felix
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