Mechanism to prevent illegal access to task address space by unauthorized tasks

A method for enabling exchange of global shared memory (GSM) operations across network-connected processing nodes within a distributed system having at least one local node with a host fabric interface (HFI) coupled to HFIs of other nodes via a network fabric, said method comprising:

• managing, via processing logic of the host fabric interface (HFI), completion of GSM operations for a task executing at the local node by dynamically assigning a HFI window within the HFI to the task to handle GSM packet generation from task-issued commands and GSM packet receipt and processing for GSM packets received at the HFI window;
• automatically tagging each global shared memory (GSM) packet that is generated by the HFI for the local task with a global job identifier (ID) of a distributed job to which the local task is affiliated;
• and
• issuing the GSM packet to the network fabric with the job ID embedded within the GSM packet;
• wherein the HFI completes operations utilizing the HFI window that enable parallel job execution via a plurality of distributed tasks that have a global shared memory (GSM) accessible by effective addresses, wherein only a first portion of effective addresses within a global address space (GAS) is mapped to the local memory, while other portions of the EAs within the GAS are mapped to other physical memory of other nodes within a GSM environment.

A computer program product comprising:

• a computer readable storage device;
• and
• program code on the computer readable storage device that when executed on a processing node with a host fabric interface (HFI) and on which a local task of a distributed job is executing, performs the functions of:
• managing completion of GSM operations for a task executing at the local node by dynamically assigning a HFI window to the task to handle GSM packet generation from task-issued commands and GSM packet receipt and processing for GSM packets received at the HFI window;
• allocating the HFI window to the local task during initialization of the task on the data processing system as a part of the distributed job;
• and
• storing the global job identification (ID) corresponding to the distributed job within the HFI window;
• receiving a GSM command issued by the local task;
• in response to receiving the GSM command, generating a GSM packet corresponding to the GSM command;
• automatically tagging each global shared memory (GSM) packet that is generated by the HFI for the local task with a global job identifier (ID) of a distributed job to which the local task is affiliated;
• and
• issuing the GSM packet to the network fabric with the job ID embedded within the GSM packet;
• wherein the HFI completes operations utilizing the HFI window that enable parallel job execution via a plurality of distributed tasks that have a global shared memory (GSM) accessible by effective addresses, wherein only a first portion of effective addresses within a global address space (GAS) is mapped to the local memory, while other portions of the EAs within the GAS are mapped to other physical memory of other nodes within a GSM environment.