INFORMATION PROCESSING DEVICE, INFORMATION PROCESSING SYSTEM, AND EXCLUSIVE CONTROL PROGRAM

• US 20160253275A1
• Filed: 02/01/2016
• Published: 09/01/2016
• Est. Priority Date: 02/26/2015
• Status: Abandoned Application

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: FUKUMORI, Masato
• Application Number:
  US15/011,716
• Publication Number:
  US 20160253275A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 13/16 for access to memory bus G06F13/28 takes precedence
• CPC Class Codes: G06F 13/364 using independent requests or grants, e.g. using separated request and grant lines

Abstract

An information processing device has process execution units that execute respective processes; a lock variable storage device that stores, with respect to a lock relating to a common resource accessed by the process execution units, a lock variable having a lock state flag and a lock identification information which is updated when lock being acquired; and an exclusive control device that executes first lock acquisition processing, including, when the lock state flag is the lock release state, updating the lock state flag to the lock acquisition state, and updating the lock identification information to newly updated one, to acquire the lock, and second lock acquisition processing, including, when the lock state flag is the lock acquisition state, updating the lock identification information to newly updated lock identification information to acquire the lock, after a time-out time elapses while the lock variable maintains the same lock identification information.

Claims

1. An information processing device comprising:

a plurality of process execution units that execute respective processes;

a lock variable storage device that stores, with respect to a lock relating to a common resource which is accessed by the plurality of process execution units, a lock variable having a lock state flag indicating a lock acquisition state and a lock release state, and a lock identification information which is updated each time the lock is acquired; and

an exclusive control device that executes

first lock acquisition processing, which includes, when the lock state flag is the lock release state, updating the lock state flag of the lock variable in the lock variable storage device to the lock acquisition state, and updating the lock identification information of the lock variable to newly updated lock identification information, to acquire the lock for the process execution unit, and

second lock acquisition processing, which includes, when the lock state flag is the lock acquisition state, updating the lock identification information of the lock variable in the lock variable storage device to newly updated lock identification information to acquire the lock for the process execution unit, after a predetermined time-out time elapses while the lock variable in the lock variable storage device maintains the same lock identification information.

2. The information processing device according to claim 1, wherein

in the first lock acquisition processing, the exclusive control device:

reads the lock variable at a predetermined timing and sets the read-out variable to an old value;

when the lock state flag of the old value is the lock release state, sets a lock variable, in which the lock state flag is the lock acquisition state and the lock identification information is the newly updated lock identification information, to a new value; and

executes, with an atomic instruction, compare-and-swap processing of comparing the old value and the lock variable in the lock variable storage device and swapping the lock variable in the lock variable storage device to the new value, provided that the result of the comparing is matched.

3. The information processing device according to claim 1, wherein

in the second lock acquisition processing, the exclusive control device:

at a first timing, when the lock state flag of the lock variable which has been read from the lock variable storage device is the lock acquisition state, starts time-out determination as to whether or not a predetermined time-out time has elapsed, while the lock variable in the lock variable storage device maintains the same lock identification information; and

at a second timing after the first timing, updates the lock identification information of the lock variable to the newly updated lock identification information when the time-out time has elapsed and when the lock identification information of the lock variable read from the lock variable storage device at the second timing is the same as the lock identification information read at the first timing.

4. The information processing device according to claim 3, wherein

in the processing of updating the lock identification information of the lock variable to the newly updated lock identification information in the second lock acquisition processing, the exclusive control device:

sets the lock variable which has been read at the second timing to the old value;

sets a lock variable, in which the lock state flag is the lock acquisition state and the lock identification information is the newly updated lock identification information, to a new value; and

executes, with an atomic instruction, compare-and-swap processing of comparing the old value and the lock variable in the lock variable storage device and swapping the lock variable in the lock variable storage device to the new value is executed with an atomic instruction, provided that the result of the comparing is matched.

5. The information processing device according to claim 1, wherein

the exclusive control device reads the lock variable from the lock variable storage device and, when the read-out lock variable matches a lock variable which has been updated at the time the lock has been acquired, executes lock release processing of updating the lock state flag of the lock variable in the lock variable storage device to the lock release state.

6. The information processing device according to claim 5, wherein

in the lock release processing, the exclusive control device:

sets the lock variable read from the lock variable storage device to n old value,

sets a lock variable in which the lock state flag is the lock release state to a new value, and

executes, with an atomic instruction, compare-and-swap processing of comparing the old value and the lock variable in the lock variable storage device and swapping the lock variable in the lock variable storage device to the new value, provided that the result of the comparing is matched.

7. An information processing system comprising:

a plurality of process execution units that execute respective processes;

a common resource which is accessed by the plurality of process execution units;

a lock variable storage device that stores, with respect to a lock relating to the common resource, a lock variable having a lock state flag indicating a lock acquisition state and a lock release state, and a lock identification information which is updated each time the lock is acquired; and

an exclusive control device that executes

first lock acquisition processing, which includes, when the lock state flag is the lock release state, updating the lock state flag of the lock variable in the lock variable storage device to the lock acquisition state, and updating the lock identification information of the lock variable to newly updated lock identification information, to acquire the lock for the process execution unit, and

second lock acquisition processing, which includes, when the lock state flag is the lock acquisition state, updating the lock identification information of the lock variable in the lock variable storage device to newly updated lock identification information to acquire the lock for the process execution unit, after a predetermined time-out time elapses while the lock variable in the lock variable storage device maintains the same lock identification information.

8. A non-transitory computer-readable storage medium storing therein an exclusive control program for causing a computer to execute a process comprising:

accessing a lock variable storage device that stores, with respect to a lock relating to a common resource which is accessed by a plurality of process execution units, each of which executes respective process, a lock variable having a lock state flag indicating a lock acquisition state and a lock release state, and a lock identification information which is updated each time the lock is acquired;

executing first lock acquisition processing, which includes, when the lock state flag is the lock release state, updating the lock state flag of the lock variable in the lock variable storage device to the lock acquisition state, and updating the lock identification information of the lock variable to newly updated lock identification information, to acquire the lock for the process execution unit, and

executing second lock acquisition processing, which includes, when the lock state flag is the lock acquisition state, updating the lock identification information of the lock variable in the lock variable storage device to newly updated lock identification information to acquire the lock for the process execution unit, after a predetermined time-out time elapses while the lock variable in the lock variable storage device maintains the same lock identification information.

9. The non-transitory computer-readable storage medium according to claim 8, wherein

in the first lock acquisition processing,

reading the lock variable at a predetermined timing and sets the read-out variable to an old value;

when the lock state flag of the old value is the lock release state, setting a lock variable, in which the lock state flag is the lock acquisition state and the lock identification information is the newly updated lock identification information, to a new value; and

executing, with an atomic instruction, compare-and-swap processing of comparing the old value and the lock variable in the lock variable storage device and swapping the lock variable in the lock variable storage device to the new value, provided that the result of the comparing is matched.

10. The non-transitory computer-readable storage medium according to claim 8, wherein

in the second lock acquisition processing, the exclusive control device:

at a first timing, when the lock state flag of the lock variable which has been read from the lock variable storage device is the lock acquisition state, starting time-out determination as to whether or not a predetermined time-out time has elapsed, while the lock variable in the lock variable storage device maintains the same lock identification information; and

at a second timing after the first timing, updating the lock identification information of the lock variable to the newly updated lock identification information when the time-out time has elapsed and when the lock identification information of the lock variable read from the lock variable storage device at the second timing is the same as the lock identification information read at the first timing.

11. The non-transitory computer-readable storage medium according to claim 10, wherein

in the processing of updating the lock identification information of the lock variable to the newly updated lock identification information in the second lock acquisition processing,

setting the lock variable which has been read at the second timing to the old value,

setting a lock variable, in which the lock state flag is the lock acquisition state and the lock identification information is the newly updated lock identification information, to a new value, and

executing, with an atomic instruction, compare-and-swap processing of comparing the old value and the lock variable in the lock variable storage device and swapping the lock variable in the lock variable storage device to the new value is executed with an atomic instruction, provided that the result of the comparing is matched.

12. The non-transitory computer-readable storage medium according to claim 8, the process further comprising:

reading the lock variable from the lock variable storage device and,

when the read-out lock variable matches a lock variable which has been updated at the time the lock has been acquired, executing lock release processing of updating the lock state flag of the lock variable in the lock variable storage device to the lock release state.