Expanding memory size

Abstract

A method for expanding memory size is provided in the illustrative embodiments. A desired size of an expanded memory and a first information about a workload in the data processing system are received. A size of a compressed memory pool to use with the memory to make the desired size of the expanded memory available is computed. A representation of the memory is configured, the representation of the memory appearing to be of a size larger than the size of the memory, the representation of the memory being the expanded memory, and the size of the representation being the size of the expanded memory. The expanded memory is made available such that the memory in the data processing system is usable by addressing the expanded memory.

1 . A computer implemented method for expanding memory size, comprising:
 receiving in a data processing system having a memory, a desired size of an expanded memory;   receiving a first information about a workload in the data processing system;   computing a size of a compressed memory pool to use with the memory to make the desired size of the expanded memory available;   configuring a representation of the memory, the representation of the memory appearing to be of a size larger than the size of the memory, the representation of the memory being the expanded memory, and the size of the representation being the size of the expanded memory; and   making available the expanded memory such that the memory in the data processing system is usable by addressing the expanded memory.   
     
     
         2 . The computer implemented method of  claim 1 , further comprising:
 receiving an input value corresponding to a performance parameter of the data processing system, wherein the configuring the representation includes determining the size of the representation based on the desired size of the expanded memory, a compression ratio of the workload, and the input value.   
     
     
         3 . The computer implemented method of  claim 2 , wherein the performance parameter is a minimum size of an uncompressed memory pool to avoid thrashing. 
     
     
         4 . The computer implemented method of  claim 1 , wherein the size of the expanded memory excludes a size of a memory space one of (i) used for storing a pinned page, (ii) used for storing a protected page, and (iii) that is reserved for use by an application. 
     
     
         5 . The computer implemented method of  claim 1 , further comprising:
 determining whether the desired size of the expanded memory can be made available; and   responsive to the determining being false, making the expanded memory available such that the size of the expanded memory is different from the desired size of the expanded memory.   
     
     
         6 . The computer implemented method of  claim 1 , further comprising:
 determining whether the desired size of the expanded memory can be made available; and   responsive to the determining being false, making the expanded memory available together with information about a portion of the desired size that cannot be made available.   
     
     
         7 . The computer implemented method of  claim 1 , further comprising:
 receiving a second information about one of (i) a change in the workload and (ii) a change in the desired size of the expanded memory;   recomputing the size of the compressed memory pool based on the second information; and   adjusting the size of the compressed memory pool while the data processing system is operational.   
     
     
         8 . The computer implemented method of  claim 7 , wherein the adjusting leaves the size of the expanded memory unchanged. 
     
     
         9 . The computer implemented method of  claim 1 , wherein the size of the expanded memory is equal to the sum of (i) a product of a compression ratio of the workload and the size of the compressed memory pool and (ii) a difference of the size of the memory and the size of the compressed memory pool. 
     
     
         10 . The computer implemented method of  claim 1 , wherein addressing the expanded memory is accomplished in the manner of addressing the memory.