Hardware Enabled Lock Mediation

Abstract

A tangible storage medium and data processing system build a runtime environment of a system. A profile manager receives a service request containing a profile identifier. The profile identifier specifies a required version of at least one software component. The profile manager identifies a complete installation of the software component, and at least one delta file. The profile manager dynamically constructs a classpath for the required version by preferentially utilizing files from the at least one delta file followed by files from the complete installation. The runtime environment is then built utilizing the classpath.

1 - 11 . (canceled) 
     
     
         12 . A computer system, wherein the computer system is a computer and wherein the computer is hardware, the computer system comprising:
 a memory, wherein the memory has computer implemented instructions encoded thereon for controlling access to a contested resource,   a bus system connecting the memory to a processor; and   a processor, wherein the processor includes a hardware extension allowing a lock instruction in a guest operating system to conditionally trap to a partition management firmware, wherein the processor executes the computer implemented instructions: to receive a lock acquisition request from a virtual machine; to determine whether the lock acquisition request for a lock is received within a preemption period of a time slice of a defined duration allocated to the virtual machine; responsive to determining that the lock acquisition request is received within the preemption period, to end the time slice prior to a conclusion of the defined duration without granting the lock to the virtual machine.   
     
     
         13 . The computer system of  claim 12 , wherein the lock is a spinlock. 
     
     
         14 . The computer system of  claim 12 , wherein the processor executes the computer implemented instructions:
 responsive to determining that the lock acquisition request is not received within the preemption period, to set a flag indicating that the virtual machine holds the lock; and to grant the lock to the virtual machine.   
     
     
         15 . The computer system of  claim 14 , wherein the processor executes the computer implemented instructions:
 responsive to an ending of the defined duration, to determine whether the flag indicating that the virtual machine holds the lock is set; and responsive to determining that the flag indicating that the virtual machine holds the lock is set, to extend the time slice allocated to the virtual machine to a duration greater than the defined duration.   
     
     
         16 . The computer system of  claim 15 , wherein extending the time slice creates an extended time slice, wherein the processor executes the computer implemented instructions:
 responsive to expiration of the extended time slice, to perform a context switch to a second virtual machine, wherein the context switch is performed by the partition management firmware.   
     
     
         17 . The computer system of  claim 15 , wherein the processor executes the computer implemented instructions:
 responsive to determining that the lock acquisition request is received within the preemption period, to execute a software invoked interrupt, wherein the software invoked interrupt extends the time slice allocated to the virtual machine.   
     
     
         18 . The computer system of  claim 12 , wherein the preemption period is a last 10% of the defined duration of the time slice. 
     
     
         19 . A computer program product for controlling access to a contested resource in a computer system, wherein the computer system is a computer and wherein the computer is hardware, the computer program product comprising:
 a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising:
 computer readable program code configured to receive a lock acquisition request from a virtual machine; 
 computer readable program code configured to determine whether the lock acquisition request for a lock is received within a preemption period of a time slice of a defined duration allocated to the virtual machine; and 
 computer readable program code configured, responsive to determining that the lock acquisition request is received within the preemption period, to end the time slice prior to a conclusion of the defined duration without granting the lock to the virtual machine. 
   
     
     
         20 . The computer program product of  claim 19 , the computer readable program code further comprising:
 computer readable program code configured, responsive to determining that the lock acquisition request is not received within the preemption period, to set a flag indicating that the virtual machine holds the lock; and   computer readable program code configured to grant the lock to the virtual machine.   
     
     
         21 . The computer program product of  claim 20 , the computer readable program code further comprising:
 computer readable program code configured, responsive to an ending of the defined duration, to determine whether the flag indicating that the virtual machine holds the lock is set; and   computer readable program code configured, responsive to determining that the flag indicating that the virtual machine holds the lock is set, to extend the time slice allocated to the virtual machine to a duration greater than the defined duration.   
     
     
         22 . The computer program product of  claim 21 , wherein extending the time slice creates an extended time slice, the computer readable program code further comprising:
 computer readable program code configured, responsive to expiration of the extended time slice, to perform a context switch to a second virtual machine, wherein the context switch is performed by a partition management firmware.   
     
     
         23 . The computer program product of  claim 21 , the computer readable program code further comprising:
 computer readable program code configured, responsive to determining that the lock acquisition request is received within the preemption period, to execute a software invoked interrupt, wherein the software invoked interrupt extends the time slice allocated to the virtual machine.