Method and system for dynamic memory management

• US 8,127,280 B2
• Filed: 06/29/2007
• Issued: 02/28/2012
• Est. Priority Date: 11/16/1998
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Myriad Group AG
• Inventors: Plummer, Wayne, Rautenbach, Keith, Wynn, Michael John, Sexton, Jeremy James, Kramskoy, Jeremy Paul, Guthrie, Philippa Joy, Dias, Blaise Abel Alec, Darnell, Stephen, Charnell, William Thomas, Thomas, Stephen Paul
• Primary Examiner(s): Ho, Andy
• Application Number:
  US11/771,629
• Publication Number:
  US 20080016507A1
• Time in Patent Office: 1,705 Days
• Field of Search: 717/136, 717/139, 717/140
• US Class Current: 717/136
• CPC Class Codes: G06F 11/3612 by runtime analysis performance monitoring G06F11/3466
• CPC Class Codes: G06F 12/0269 Incremental or concurrent garbage collection, e.g. in real-time systems G06F12/0261 takes precedence
• CPC Class Codes: G06F 2209/481 Exception handling
• CPC Class Codes: G06F 8/4442 Reducing the number of cache misses; Data prefetching cache prefetching G06F12/0862
• CPC Class Codes: G06F 8/445 Exploiting fine grain parallelism, i.e. parallelism at instruction level run-time instruction scheduling G06F9/3836
• CPC Class Codes: G06F 9/4484 Executing subprograms
• CPC Class Codes: G06F 9/449 Object-oriented method invocation or resolution
• CPC Class Codes: G06F 9/4491 Optimising based on receiver type
• CPC Class Codes: G06F 9/455 Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines
• CPC Class Codes: G06F 9/45516 Runtime code conversion or optimisation
• CPC Class Codes: G06F 9/4812 by interrupt, e.g. masked
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99956 File allocation

Abstract

A computer system which includes a plurality of threads and a garbage collector that traces memory objects and identifies memory objects according to a three-color abstraction. The computer system also includes two methods of deleting compiled code in a self-modifying multi-threaded computer system. The computer system also utilizes a method of handling links between fragments of code in a self-modifying multi-threaded computer system. The computer system also handles patches between two pieces of code.

Claims

1. A method of deleting compiled code in a self-modifying multi-threaded computer system, the method comprising:

selecting a section of compiled code to be deleted;

identifying any patches in the section of compiled code;

redirecting any identified patches to other code; and

deleting the section of compiled code.

2. A method as claimed in claim 1, wherein the section of compiled code to be deleted has a range of addresses, the method further comprising:

examining a frame of a stack in the computer system;

identifying whether the frame contains a return address that is in the range of addresses of the section of compiled code to be deleted; and

altering the contents of the frame in the event that the frame contains a return address that is in the range of addresses of the section of compiled code to be deleted.

3. A method of deleting compiled code in a self-modifying multi-threaded computer system, the method comprising:

selecting a code buffer to delete, the code buffer having an address;

generating a hash of the address of the code buffer;

selecting a patch block;

identifying whether there is a patch into the code buffer to be deleted;

if a patch into the bode buffer is identified, redirecting the identified patch to other code; and

deleting the code buffer.

4. A method of handling links between fragments of code in a self-modifying multi-threaded computer system, the method comprising:

creating patches between compiled pieces of code;

storing information in a patch block about each patch as it is made, each patch block including a from address and a to address;

configuring the patch blocks in a from chain and a to chain;

selecting a code buffer to delete, the code buffer having an address;

generating a hash of the address of the code buffer;

selecting a patch block;

identifying whether there is a patch into the code buffer to be deleted;

if a patch into the code buffer is identified, redirecting the identified patch to other code;

selecting a patch from the from chain;

generating a hash of the selected patch from the from chain;

removing the patch block from the from chain; and

deleting the selected code buffer.

5. A system having at least one processor for handling patches between two pieces of code, the processor comprising:

a control device having access to glue code and at least one patch;

a deleter coupled to the control device;

an interpreter coupled to the control device;

a compiler coupled to the control device; and

a hash table coupled to the control device.