dax: add an instance manager

[checkupup]

When multiple DAX components are running simultaneously, instance resources may be insufficient. In this case, DAX instance manager ensures that higher-priority DAX components are always granted instance resources. For DAX components that cannot obtain instance resources in a timely manner, dax_process will operate in pass-through mode.

[sofci]

Can one of the admins verify this patch?

reply test this please to run this test once

[lgirdwood]

test this please

[lgirdwood]

@checkupup are you able to add more inline comments describing the flow/mechanism and log when we have to fallback to pass through mode. How would priority be set by users, i.e. using topology tuples would mean same dax/sof binaries could be used but with different priorities depending on target.

[checkupup]

@checkupup are you able to add more inline comments describing the flow/mechanism and log when we have to fallback to pass through mode.

Sure, see my latest commit.

[checkupup]

To maintain code readability, I have extracted the entire instance resource handling logic into the file dax_instance_manager.c

[checkupup]

Code Logic:

Assume that instance 1 is created first.

While Instance 1 is running, Instance 2 requests to be created. If Instance 2 has a higher priority than Instance 1, then during Instance 1's process loop, check_priority_l evaluates to false, causing Instance 1 to voluntarily release its held memory resources. Instance 2 checks for available memory on each iteration of its process loop; if memory is available, it proceeds to create the instance. Since Instance 1 has already released its memory, Instance 2 is successfully created. At this point, Instance 1 operates in passthrough mode.

Once Instance 2 finishes its work and releases the memory, if Instance 1 is still active, check_priority_l in its process loop evaluates to true. Instance 1 then re-requests the memory resources. Upon successfully acquiring them, it exits passthrough mode and resumes actual audio effect processing.

Note: The speaker instance has a higher priority than the headphone instance.

[kv2019i]

Some comments inline.

[kv2019i]

Thanks @checkupup , looks good now!

[checkupup]

Hi, @johnylin76 @lgirdwood Could you please review this change? Thx.