Managing memory allocation between input/output adapter caches

A computer system comprising:

• a first input/output adapter (IOA) configured to receive and route input/output (I/O) requests;
• a first cache of the first IOA;
• a second IOA configured to receive and route I/O requests;
• a second cache of the second IOA;
• an I/O bus communicatively coupling the first IOA to the second IOA such that messages may be sent directly between the first IOA and the second IOA;
• and
• a first dedicated processing circuit communicatively coupled to the first IOA and a second dedicated processing circuit communicatively coupled to the second IOA, wherein the first and second dedicated processing circuits are configured to:
• detect the first cache storing a first amount of data that satisfies a memory shortage threshold of the first cache;
• transmit a first request for extra memory for the first cache in response to detecting that the first amount of data satisfies the memory shortage threshold, wherein the first request is transmitted to a plurality of IOAs;
• detect the second cache of the plurality of IOAs storing a second amount of data that satisfies a memory dissemination threshold of the second cache;
• and
• allocate memory from the second cache to the first cache in response to both the first request and detecting that the second amount of data satisfies the memory dissemination threshold.

A computer program product for managing memory allocation of input/output adapters (IOAs), the computer program product disposed upon a computer readable storage medium, the computer program product comprising computer program instructions that, when executed by a computer processor of a computer, cause the computer to:

• detect a first cache of a first IOA storing a first amount of data that satisfies a memory shortage threshold of the first cache;
• transmit a first request for extra memory for the first cache in response to detecting that the first amount of data satisfies the memory shortage threshold, wherein the first request is transmitted to a plurality of IOAs;
• detect a second cache of a second IOA of the plurality of IOAs storing a second amount of data that satisfies a memory dissemination threshold of the second cache;
• and
• allocate memory from the second cache to the first cache in response to both the first request and detecting that the second amount of data satisfies the memory dissemination threshold.