... as this can lead to a deadlock with the following sequence:
Time1: guest-thread-1: vkDestroyBuffer() called
Time2: VkEncoder grabs seqno 1
Time3: guest-thread-2: vkMapMemory() called
Time4: ResourceTracker::on_vkMapMemory() locks mLock
for using `info_VkDeviceMemory`
Time5: ResourceTracker::on_vkMapMemory() calls
enc->vkGetBlobGOOGLE()
Time6: VkEncoder grabs seqno 2
Time7: VkEncoder sends the vkGetBlobGOOGLE with seqno
2 via ASG to host
Time8: VkEncoder waits for the `VkResult` from the
host via `stream->read()`
Time9: guest-thread-1: VkEncoder calls sResourceTracker->destroyMapping()
->mapHandles_VkBuffer((VkBuffer*)&buffer);
which calls ResourceTracker::unregister_VkBuffer()
ResourceTracker::unregister_VkBuffer() tries to
locks mLock to erase the buffer's info struct
from `info_VkBuffer`
!!! DEADLOCKED HERE !!!
guest-thread-1 is stuck waiting on mLock (currently locked by
guest-thread-2) before it would `stream->flush();` to finishing
sending the vkDestroyBuffer() command to the host and potentially
ping its corresponding host-render-thread-1.
guest-thread-2 stuck waiting on the result from host-render-thread-2
but host-render-thread-2 won't progress until host-render-thread-1
finishes seqno 1 which needs guest-thread-1 to finish sending/pinging.
Reviewed-by: Aaron Ruby <aruby@blackberry.com>
Acked-by: Yonggang Luo <luoyonggang@gmail.com>
Acked-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27246>
Jason Macnak
6d2dd9c22f