Balancing the block wearing leveling for optimum SSD endurance
In one embodiment, there is a method for implementing balancing block wearing leveling at a storage device including one or more single level cell (SLC) blocks in a SLC block pool and one or more non-single level cell (nSLC) blocks in a nSLC block pool for storing data and a memory controller for performing operations on the SLC blocks and nSLC blocks, the method comprising: at the memory controller: receiving a first request to perform a wear leveling operation on a respective block pool of one of: the SLC block pool and the nSLC block pool; determining whether one or more blocks in the respective block pool meet block pool transfer criteria; in response to a determination that the one or more blocks in the respective block pool meets block pool transfer criteria, reclassifying the one or more blocks in the respective block pool as the other of the SLC block pool and the nSLC block pool; and in response to a determination that the one or more blocks in the respective block pool does not meet block pool transfer criteria, refraining from reclassifying the one or more blocks in the respective block pool as the other of the SLC block pool and the nSLC block pool.
1. A method for implementing balancing block wear leveling at a storage device including one or more first level-type blocks in a first level-type block pool and one or more second level-type blocks in a second level-type block pool for storing data, the method comprising:
receiving a first request or first instruction to perform a wear leveling operation on a respective block pool of one of: the first level-type block pool and the second level-type block pool;
in response to receiving the first request or first instruction to perform a wear leveling operation:
determining whether one or more blocks in the respective block pool meet block pool transfer criteria,
in response to a determination that the one or more blocks in the respective block pool meets block pool transfer criteria, reclassifying the one or more blocks in the respective block pool as the other of the first level-type block pool and the second level-type block pool, and
in response to a determination that the one or more blocks in the respective block pool does not meet block pool transfer criteria, refraining from reclassifying the one or more blocks in the respective block pool as the other of the first level-type block pool and the second level-type block pool;
wherein the respective block pool is the first level-type block pool; and
wherein the block pool transfer criteria is met when a program erase cycle (PEC) count for the one or more first level-type blocks is less than a sum of an average PEC count of the one or more second level-type blocks in the second level-type block pool and a second level-type block wear leveling threshold.
2. The method of claim 1 , wherein the block pool transfer criteria includes a criterion that is met when the PEC count for one or more of the first level-type blocks in the first level-type block pool is less than a second level-type wear leveling threshold.
3. The method of claim 2 , wherein the second level-type wear leveling threshold is a predetermined maximum PEC count difference between a second level-type block with a highest PEC count in the second level-type block pool and an second level-type block with a lowest PEC count in the second level-type block pool.
4. The method of claim 1 , further comprising: in response to a determination that the one or more blocks in the respective block pool meets block pool transfer criteria, reclassifying one or more second level-type blocks in the second level-type block pool as one or more first level-type blocks, wherein each of the one or more second level-type blocks have a program erase cycle count greater than a program erase cycle count of the other second level-type blocks in the second level-type block pool.
5. The method of claim 1 , further comprising:
reclassifying one or more second level-type blocks in the second level-type block pool as one or more first level-type blocks in the first level-type block pool including multiplying a corresponding PEC count for each of the one or more second level-type blocks by a first level-type conversion factor.
6. A storage device including one or more first level blocks in a first level block pool and one or more second level blocks in a second level block pool for storing data, the storage device comprising:
means for receiving a first request or first instruction to perform a wear leveling operation on a respective block pool of one of: the first level block pool and the second level block pool;
in response to receiving the first request or first instruction to perform a wear leveling operation:
means for determining whether one or more blocks in the respective block pool meet block pool transfer criteria,
in response to a determination that the one or more blocks in the respective block pool meets block pool transfer criteria, means for reclassifying the one or more blocks in the respective block pool as the other of the first level block pool and the second level block pool, and
in response to a determination that the one or more blocks in the respective block pool does not meet block pool transfer criteria, means for refraining from reclassifying the one or more blocks in the respective block pool as the other of the first level block pool and the second level block pool;
wherein the respective block pool is the first level block pool; and
wherein the block pool transfer criteria is met when a program erase cycle (PEC) count for the one or more first level blocks is less than a sum of an average PEC count of the one or more second level blocks in the second level block pool and a second level wear leveling threshold.
7. The storage device of claim 6 , wherein the block pool transfer criteria include a criterion that is met when the PEC count for one or more of the first level blocks in the first level block pool is less than a second level block wear leveling threshold.
8. The storage device of claim 7 , wherein the second level block wear leveling threshold is a predetermined maximum PEC count difference between a second level-type block with a highest PEC count in the second level block pool and an second level block with a lowest PEC count in the second level block pool.
9. The storage device of claim 6 , the storage device including in response to a determination that the one or more blocks in the respective block pool meets block pool transfer criteria, means for reclassifying one or more second level blocks in the second level block pool as one or more first level blocks, wherein each of the one or more second level blocks have a program erase cycle count greater than a program erase cycle count of the other second level-type blocks in the second level block pool.
10. The storage device of claim 6 , the storage device including:
means for reclassifying one or more second level blocks in the second level block pool as one or more first level blocks in the first level block pool including multiplying a corresponding PEC count for each of the one or more second level blocks by a first level conversion factor.
11. A memory controller for performing operations on single level cell (SLC) blocks and non-single level cell (non-SLC) blocks, the memory controller configured to perform the operations of:
receiving a first request or first instruction to perform a wear leveling operation on a respective SLC block pool;
in response to receiving the first request or first instruction to perform a wear leveling operation:
determining whether one or more SLC blocks in the respective SLC block pool meet block pool transfer criteria,
in response to a determination that the one or more SLC blocks in the respective SLC block pool meets the block pool transfer criteria, reclassifying the one or more SLC blocks in the respective SLC block pool to a non-SLC block pool, and
in response to a determination that the one or more SLC blocks in the respective SLC block pool does not meet the block pool transfer criteria, refraining from reclassifying the one or more SLC blocks in the respective SLC block pool to the non-SLC block pool; and
wherein the block pool transfer criteria is met when a program erase cycle (PEC) count for the one or more SLC blocks is less than a sum of an average PEC count of the one or more non-SLC blocks in the non-SLC block pool and a non-SLC block wear leveling threshold.
12. The memory controller of claim 11 , wherein the block pool transfer criteria include a criterion that is met when the PEC count for one or more of the SLC blocks in the SLC block pool is less than a non-SLC block wear leveling threshold.
13. The memory controller of claim 12 , wherein the non-SLC block wear leveling threshold is a predetermined maximum PEC count difference between a non-SLC block with a highest PEC count in the non-SLC block pool and a non-SLC block with a lowest PEC count in the non-SLC block pool.
14. The memory controller of claim 11 , the memory controller configured to perform the operations of:
reclassifying one or more non-SLC blocks in the non-SLC block pool as one or more SLC blocks in the SLC block pool including multiplying a corresponding PEC count for each of the one or more non-SLC blocks by a first level conversion factor.