Abstract: Read-copy-update (RCU) is performed within real-time and other types of systems, such that memory barrier usage within RCU is reduced. A computerized system includes processors, memory, updaters, and readers. The updaters update contents of a section of the memory by using first and second sets of per-processor counters, first and second sets of per-processor need-memory-barrier bits, and a global flip-counter bit. The global flip-counter bit specifies which of the first or second set of the per-processor counters and the per-processor need-memory-barrier bits is a current set, and which is a last set. The readers read the contents of the section of the memory by using the first and second sets of per-processor counters, the first and second sets of per-processor need-memory-barrier bits, and the global flip-counter bit, in a way that significantly reduces the need for memory barriers during such read operations.

Abstract: Read-copy-update (RCU) is performed within real-time and other types of systems, such that memory barrier usage within RCU is reduced. A computerized system includes processors, memory, updaters, and readers. The updaters update contents of a section of the memory by using first and second sets of per-processor counters, first and second sets of per-processor need-memory-barrier bits, and a global flip-counter bit. The global flip-counter bit specifies which of the first or second set of the per-processor counters and the per-processor need-memory-barrier bits is a current set, and which is a last set. The readers read the contents of the section of the memory by using the first and second sets of per-processor counters, the first and second sets of per-processor need-memory-barrier bits, and the global flip-counter bit, in a way that eliminates the need for memory barriers during such read operations.

Abstract: A technique for efficiently boosting the priority of a preemptable data reader in order to eliminate impediments to grace period processing that defers the destruction of one or more shared data elements that may be referenced by the reader until the reader is no longer capable of referencing the data elements. Upon the reader being subject to preemption or blocking, it is determined whether the reader is in a read-side critical section referencing any of the shared data elements. If it is, the reader's priority is boosted in order to expedite completion of the critical section. The reader's priority is subsequently decreased after the critical section has completed. In this way, delays in grace period processing due to reader preemption within the critical section, which can result in an out-of-memory condition, can be minimized efficiently with minimal processing overhead.

Abstract: A method and system for accessing, from a mirror probe handler, a value to be associated with an argument of a function. The mirror probe handler and the function are defined with identical prototypes and compiled with identical linkage conventions. The mirror probe handler is executed after initiating execution of the function, executing a probe placed in the function, and saving a state of processor registers. While executing the mirror probe handler, a reference to an argument of the mirror probe handler seamlessly accesses the value via automatically employing at least one of the processor registers. The access is facilitated by the identical prototypes and the compilations with identical linkage conventions. After the reference accesses the value, the saved state is restored, which facilitates the execution of the function, which was temporarily replaced by the execution of the probe and mirror probe handler.

Abstract: A method and apparatus are provided for pre-allocating non-initialized blocks of data in a file system. Each file contains a primary i-node to maintain file metadata. A secondary i-node is created and associated with the primary i-node. The secondary i-node contains non-initialized data blocks, and the primary i-node contains valid and initialized data blocks. A write operation to a non-initialized data block in a pre-allocated range stored in the secondary i-node directs the data block from the secondary i-node to the primary i-node.

Abstract: Read-copy-update (RCU) is performed within real-time and other types of systems, such that memory barrier usage within RCU is reduced. A computerized system includes processors, memory, updaters, and readers. The updaters update contents of a section of the memory by using first and second sets of per-processor counters, first and second sets of per-processor need-memory-barrier bits, and a global flip-counter bit. The global flip-counter bit specifies which of the first or second set of the per-processor counters and the per-processor need-memory-barrier bits is a current set, and which is a last set. The readers read the contents of the section of the memory by using the first and second sets of per-processor counters, the first and second sets of per-processor need-memory-barrier bits, and the global flip-counter bit, in a way that significantly reduces the need for memory barriers during such read operations.

Abstract: Read-copy-update (RCU) is performed within real-time and other types of systems, such that memory barrier usage within RCU is reduced. A computerized system includes processors, memory, updaters, and readers. The updaters update contents of a section of the memory by using first and second sets of per-processor counters, first and second sets of per-processor need-memory-barrier bits, and a global flip-counter bit. The global flip-counter bit specifies which of the first or second set of the per-processor counters and the per-processor need-memory-barrier bits is a current set, and which is a last set. The readers read the contents of the section of the memory by using the first and second sets of per-processor counters, the first and second sets of per-processor need-memory-barrier bits, and the global flip-counter bit, in a way that significantly reduces the need for memory barriers during such read operations.

Abstract: A technique for efficiently boosting the priority of a preemptable data reader in order to eliminate impediments to grace period processing that defers the destruction of one or more shared data elements that may be referenced by the reader until the reader is no longer capable of referencing the data elements. Upon the reader being subject to preemption or blocking, it is determined whether the reader is in a read-side critical section referencing any of the shared data elements. If it is, the reader's priority is boosted in order to expedite completion of the critical section. The reader's priority is subsequently decreased after the critical section has completed.

Abstract: Read-copy-update (RCU) is performed within real-time and other types of systems, such that memory barrier usage within RCU is reduced. A computerized system includes processors, memory, updaters, and readers. The updaters update contents of a section of the memory by using first and second sets of per-processor counters, first and second sets of per-processor need-memory-barrier bits, and a global flip-counter bit. The global flip-counter bit specifies which of the first or second set of the per-processor counters and the per-processor need-memory-barrier bits is a current set, and which is a last set. The readers read the contents of the section of the memory by using the first and second sets of per-processor counters, the first and second sets of per-processor need-memory-barrier bits, and the global flip-counter bit, in a way that significantly reduces the need for memory barriers during such read operations.

Abstract: Read-copy-update (RCU) is performed within real-time and other types of systems, such that memory barrier usage within RCU is reduced. A computerized system includes processors, memory, updaters, and readers. The updaters update contents of a section of the memory by using first and second sets of per-processor counters, first and second sets of per-processor need-memory-barrier bits, and a global flip-counter bit. The global flip-counter bit specifies which of the first or second set of the per-processor counters and the per-processor need-memory-barrier bits is a current set, and which is a last set. The readers read the contents of the section of the memory by using the first and second sets of per-processor counters, the first and second sets of per-processor need-memory-barrier bits, and the global flip-counter bit, in a way that eliminates the need for memory barriers during such read operations.

Abstract: A method and system for accessing, from a mirror probe handler, a value to be associated with an argument of a function. The mirror probe handler and the function are defined with identical prototypes and compiled with identical linkage conventions. The mirror probe handler is executed after initiating execution of the function, executing a probe placed in the function, and saving a state of processor registers. While executing the mirror probe handler, a reference to an argument of the mirror probe handler seamlessly accesses the value via automatically employing at least one of the processor registers. The access is facilitated by the identical prototypes and the compilations with identical linkage conventions. After the reference accesses the value, the saved state is restored, which facilitates the execution of the function, which was temporarily replaced by the execution of the probe and mirror probe handler.

Abstract: A method is provided that allows a general set of watchpoints to be defined for a computer system (a watchpoint is a memory address that triggers an interrupt for debugging or tracing purposes). This is accomplished by modifying the system page table for the memory page containing a watchpoint, such that a page fault interrupt is triggered whenever said memory page is accessed (for example by marking the page as not present). The paging mechanism of the computer system is then adapted, so that responsive to a page fault interrupt, a determination is made as to whether such interrupt has resulted from an access to the watchpoint, and if so, control is passed to a watchpoint handler. Alternatively, if there is no watchpoint, normal paging operations can be resumed if necessary.

Abstract: A method, an apparatus, and a computer program product for inserting one or more global breakpoints for debugging computer software. A method, an apparatus, and a computer program product for removing one or more global breakpoints for debugging computer software. The inserting method includes the steps of: inserting a global breakpoint in a page containing software code if the page is present in memory; reading the page into memory if not present in memory, and inserting a global breakpoint in the page immediately after being read into memory; and detecting a private copy of the page if present, and inserting a global breakpoint in the private copy.

Abstract: A method, an apparatus, and a computer program product for detecting one or more zombie global breakpoints for debugging computer software are disclosed. The method includes the steps of: checking a breakpoint data structure to determine if a breakpoint known to a debugging process is at an address where a breakpoint fired; if a known breakpoint cannot be determined at the address, verifying if a breakpoint condition continues to exist at the address where the breakpoint fired; and if the breakpoint condition does not exist, identifying the breakpoint as a zombie breakpoint.

Abstract: A system and a computer program product are disclosed for maintaining consistency of object content (252) and metadata (204) related to the object (252) in a loose transaction model, preferably using SQL Mediated Object Manipulation (SMOM), for object and meta-data updates. The related meta-data (204) and a reference to the object (252) are stored in a table of a database. The object is stored externally to the database in an object store. The reference is used to obtain a handle for directly accessing or manipulating the external object. A version number embedded in the handle is then obtained. The embedded version number is then compared with a version number of a latest committed version of the externally stored object to determine if the handle refers to a current version of the externally stored object. Next, the last modification timestamp of the file is compared with the last modification timestamp of the latest committed version, in order to detect uncommitted updates.

Abstract: A method, an apparatus, a system, a computer program product, and a computer program are disclosed for maintaining consistency of object content (252) and metadata (204) related to the object (252) in a loose transaction model, preferably using SQL Mediated Object Manipulation (SMOM), for object and meta-data updates. The related meta-data (204) and a reference to the object (252) are stored in a table of a database. The object is stored externally to the database in an object store. The reference is used to obtain a handle for directly accessing or manipulating the external object. A version number embedded in the handle is then obtained. The embedded version number is then compared with a version number of a latest committed version of the externally stored object to determine if the handle refers to a current version of the externally stored object.

Abstract: A method, a computer-implemented apparatus, and a computer program product for identifying a global breakpoint for debugging computer software are disclosed. The method includes the step of representing the global breakpoint in software code using an identifier of an executable file and an offset in the executable file. Preferably, the file identifier is an inode of a Unix or Unix-like operating system.

Abstract: A client-server computing system is disclosed for supporting relational database records and linked external files. The system comprises one or more servers for storing external files, and a plurality of clients interlinked by a network. Each of the servers and certain of the clients have respective filter layers for controlling servicing of application requests relating to external files, for any application command of a protected class relating to an external file made to a client having a filter layer, the respective client filter layer determines the presence of a valid user token associated with the command, then passes the command to a server across the network. The server filter layer, if it recognizes the command, causes the command to be serviced by the server.

Abstract: A method is provided that allows a general set of watchpoints to be defined for a computer system (a watchpoint is a memory address that triggers an interrupt for debugging or tracing purposes). This is accomplished by modifying the system page table for the memory page containing a watchpoint, such that a page fault interrupt is triggered whenever said memory page is accessed (for example by marking the page as not present). The paging mechanism of the computer system is then adapted, so that responsive to a page fault interrupt, a determination is made as to whether such interrupt has resulted from an access to the watchpoint, and if so, control is passed to a watchpoint handler. Alternatively, if there is no watchpoint, normal paging operations can be resumed if necessary.

Abstract: A method, an apparatus, a system, a computer program product, and a computer program are disclosed for maintaining consistency of object content (252) and metadata (204) related to the object (252) in a loose transaction model, preferably using SQL Mediated Object Manipulation (SMOM), for object and meta-data updates. The related meta-data (204) and a reference to the object (252) are stored in a table of a database. The object is stored externally to the database in an object store. The reference is used to obtain a handle for directly accessing or manipulating the external object. A version number embedded in the handle is then obtained. The embedded version number is then compared with a version number of a latest committed version of the externally stored object to determine if the handle refers to a current version of the externally stored object.