Finalizable object usage in software transactions

• US 7,650,371 B2
• Filed: 12/14/2006
• Issued: 01/19/2010
• Est. Priority Date: 12/14/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Duffy, John Joseph, Detlefs, David, Magruder, Michael M.
• Primary Examiner(s): Pham; Khanh B
• Assistant Examiner(s): HARPER, ELIYAH STONE
• Application Number:
  US11/639,021
• Publication Number:
  US 20080147757A1
• Time in Patent Office: 1,132 Days
• Field of Search: 707/104.1, 707/100, 707/10, 707/206, 707/205, 711/170, 711/173
• US Class Current: 707/813
• CPC Class Codes: G06F 12/0253 Garbage collection, i.e. reclamation of unreferenced memory
• CPC Class Codes: G06F 16/289 Object oriented databases
• CPC Class Codes: G06F 8/24 Object-oriented

Abstract

Various technologies and techniques are disclosed for providing a software transactional memory system that supports allocation and use of finalizable objects inside transactions. By supporting such finalizable object usage inside a software transactional memory system, correct behavior is maintained when a garbage collector must determine when a particular one or more of the objects are eligible for finalization. A to-be-finalized set is provided for a transaction. An object is placed into the to-be-finalized set for the transaction whenever a finalizable object is allocated within the transaction. A finalize indicator is set for each object in the to-be-finalized set at an appropriate time to indicate that the objects are eligible for finalization. For example, if the transaction is ready to commit and the transaction is an open transaction, then the to-be-finalized set is traversed and a finalize indicator is set for each object to indicate they are eligible for finalization.

Claims

1. A method for using finalizable objects in transactions in a software transactional memory system operating on a computing device, comprising the steps of:

providing a software transactional memory system in a managed code environment comprising a garbage collector that reclaims memory used by a transaction, the software transactional memory system controls access to shared memory in a concurrent computing system;

providing a to-be-finalized set for the transaction in the software transactional memory system that supports allocation of finalizable objects inside the transaction to indicate to the garbage collector that a particular one or more of the objects are eligible for finalization;

allocating a finalizable object within the transaction;

placing an object into the to-be-finalized set for the transaction upon allocation of the finalizable object;

determining whether the transaction is to be committed;

if the transaction is to be committed, determining whether the transaction is a closed, flattened or parallel nesting transaction; and

if the transaction is a closed, flattened or parallel nesting transaction, copying contents of the to-be-finalized set for the transaction to a to-be-finalized set of a parent transaction of the transaction

if the transaction is not a closed, flattened or parallel nesting transaction, traversing contents of the to-be-finalized set for the transaction setting an indicator to indicate the finalizable object is eligible for finalization by the garbage collector;

if the transaction is not to be committed, determining whether the transaction is to be rolled back; and

, if the transaction is to be rolled back, discarding contents of the to-be-finalized set for the transaction.

2. The method of claim 1, wherein if a request is made from the transaction to suppress a finalization operation for a particular object created within the transaction, the particular object is removed from the to-be-finalized set for the transaction.

3. The method of claim 1, wherein if a request is made from the transaction to re-register for a finalize operation for a particular object created within the transaction, the particular object is added to the to-be-finalized set for the transaction.

4. The method of claim 1, wherein if a request is made from the transaction to suppress a finalization operation for a particular object that was not created within the transaction, then a REDO action results.

5. The method of claim 1, wherein if a request is made from the transaction to re-register for a finalize operation for a particular object that was not created within the transaction, then a REDO action results.

6. A computer-readable medium having computer-executable instructions for causing a computer to perform the steps recited in claim 1.

7. A computer-readable medium having computer-executable instructions for causing a computer to perform steps comprising:

provide a software transactional memory system in a managed code environment comprising a garbage collector that reclaims memory used by a transaction, the software transactional memory system supports allocation of finalizable objects inside a transaction;

provide a to-be-finalized set for a transaction;

allocate a finalizable object within the transaction;

place an object into the to-be-finalized set for the transaction upon allocation of the finalizable object within the transaction;

determining whether the transaction is to be committed;

if the transaction is to be committed, determining whether the transaction is a closed, flattened or parallel nesting transaction; and

if the transaction is a closed, flattened or parallel nesting transaction, copying contents of the to-be-finalized set for the transaction to a to-be-finalized set of a parent transaction of the transaction

if the transaction is not a closed, flattened or parallel nesting transaction, traversing contents of the to-be-finalized set for the transaction setting an indicator to indicate the finalizable object is eligible for finalization by the garbage collector;

if the transaction is not to be committed, determining whether the transaction is to be rolled back; and

, if the transaction is to be rolled back, discarding contents of the to-be-finalized set for the transaction.

8. A method for using finalizable objects in transactions in a software transactional memory system operating on a computing device, comprising the steps of:

providing a software transactional memory system in a managed code environment comprising a garbage collector that reclaims memory used by a transaction, the software transactional memory system supports allocation of finalizable objects inside a transaction;

creating a to-be-finalized set for a transaction;

whenever a finalizable object is allocated while a transaction is alive, placing the finalizable object into the to-be-finalized set for the transaction; and

if the transaction is ready to commit, determining whether the transaction is a closed, flattened or parallel nesting transaction;

if the transaction is a closed, flattened or parallel nesting transaction, copying contents of the to-be-finalized set for the transaction to a to-be-finalized set of a parent transaction of the transaction; and

if the transaction is an open nested or non-nested transaction, then traversing the to-be-finalized set and setting a finalize indicator for each object to indicate to the garbage collector that each object is eligible to finalize

if the transaction is not a closed, flattened or parallel nesting transaction, traversing contents of the to-be-finalized set for the transaction setting an indicator to indicate the finalizable object is eligible for finalization by the garbage collector;

if the transaction is not ready to be committed, determining whether the transaction is to be rolled back; and

, if the transaction is to be rolled back, discarding contents of the to-be-finalized set for the transaction.

9. The method of claim 8, further comprising:

if the transaction is ready to commit, performing at least one other task associated with the commit.

10. The method of claim 8, further comprising:

if the transaction is ready to rollback, performing at least one other task associated with the rollback.

11. The method of claim 8, wherein the finalize indicator is set to a value of True for each object in the to-be-finalized set to indicate when each object is ready to be finalized.

12. A computer-readable medium having computer-executable instructions for causing a computer to perform the steps recited in claim 8.