Excess CMB utilization by storage controller
A controller memory buffer (CMB) is a portion of volatile memory of a controller of a data storage device that is allocated to a host device for use by the host device. When the CMB is not fully utilized, the controller may determine that at least a portion of the unutilized space of the CMB may be used for non-host data. The at least a portion is based on a number of past workloads and a current workload of the CMB. An amount of available space of the CMB that the controller may utilize is dependent on the number of past workloads and the current workload of the CMB. Thus, the volatile memory of the controller may be more optimally utilized.
1. A data storage device, comprising:
a memory device; and
a controller coupled to the memory device, wherein the controller comprises:
a volatile memory device, wherein the volatile memory device comprises a controller memory buffer (CMB), wherein the CMB is allocated to a host device for use by the host device; and
a CMB allocation module, wherein the CMB allocation module is configured to:
analyze a usage pattern of the CMB, wherein analyzing the usage pattern of the CMB comprises analyzing a number of past workloads of the CMB and a current workload of the CMB;
determine whether a portion of the CMB can be used by the controller based on the usage pattern; and
notify the controller of the portion of the CMB that can be used by the controller based on the determining; and
wherein the controller is configured to:
utilize the portion of the CMB for management data, responsive to the notifying, wherein the portion of the CMB remains allocated to the host device.
2. The data storage device of claim 1 , wherein the CMB allocation module is further configured to provide the usage pattern to the controller.
3. The data storage device of claim 1 , wherein the portion of the CMB is an amount of memory not utilized by the host device.
4. The data storage device of claim 1 , wherein the portion of the CMB is an area where data is programmed and read once.
5. The data storage device of claim 4 , wherein utilizing the portion of the CMB occurs after the data has been read once.
6. The data storage device of claim 1 , wherein the management data comprises one or more of:
cached data;
read look ahead data;
a portion of a relink table;
garbage collection data; and
exception handling data.