International Business Machines Corporation

Stephen Bailey Peckham

Khalid Filali-Adib

David W Sheffield

Frederic Barrat

Sungjin Yook

Laurent Dufour

Donald Ray Stence

Marc Joel Stephenson

Perinkulam I Ganesh

John Mark McConaughy

Philippe Bergheaud

Nathaniel S Tomsic

Luke Mathew Browning

Christophe Lombard

Guy Menanteau

Christine M Briand

J Mark McConaughy

Clifford Jay Spinac

Eric Philip Fried

Basu Vaidyanathan

David Alan Hepkin

Alfredo V Mendoza

Tiffany Lynn Winman

Provided are techniques for an operating system (OS) to be modified on a running system such that running programs, including system services, so not have to be stopped and restarted for the modification to take effect. The techniques include detecting, by a processing thread, when the processing thread has entered a shared library; in response to the detecting, setting a thread flag corresponding to the thread in an operating system (OS); detecting an OS flag, set by the OS, indicating that the OS is updating the shared library; in response to detecting the OS flag, suspending processing by the processing thread and transferring control from the thread to the OS; resuming processing by the processing thread in response to detecting that the OS has completed the updating; and executing the shared library in response to the resuming.

Dynamic library replacement

Mechanisms are provided for performing a live update of an operating system. The mechanisms receive an update to an operating system and clone a root volume group associated with an operating system instance executing in a first logical partition of the data processing system to generate a cloned root volume group. The mechanisms apply the update to the cloned root volume group to generate an updated and cloned root volume group and boot a second logical partition of the data processing system using the updated and cloned root volume group. Moreover, the mechanisms migrate application instances and application data to the second logical partition.

Live operating system update mechanisms

Provided are techniques for comparing a first fileset associated with a first operating system (OS) with a second fileset associated with a second OS; determining, based upon the comparing, that the second OS is a more current version of the first OS; in response to the determining that the second OS is a more current version of the first OS, moving, in conjunction with live application mobility, a virtual machine (VM) workload partition (WPAR) on the first LPAR to a second LPAR, the moving comprising determining a set of overlays associated with the WPAR corresponding to the second OS; removing from the WPAR any overlays associated with the first OS; applying to the WPAR a set of overlays corresponding to the second OS; check pointing processes associated with the WAPR; and copying live data associated with the LPAR from the first LPAR to the second LPAR.

Live application mobility from one operating system level to an updated operating system level and applying overlay files to the updated operating system

Provided are techniques for an OS to be modified on a running system such that running programs, including system services, so not have to be stopped and restarted for the modification to take effect. The techniques include detecting, by a processing thread, when the processing thread has entered a shared library; in response to the detecting, setting a thread flag corresponding to the thread in an operating system (OS); detecting an OS flag, set by the OS, indicating that the OS is updating the shared library; in response to detecting the OS flag, suspending processing by the processing thread and transferring control from the thread to the OS; resuming processing by the processing thread in response to detecting that the OS has completed the updating; and executing the shared library in response to the resuming.

Provided are techniques for comparing a first fileset associated with a first operating system (OS) with a second fileset associated with a second OS; determining, based upon the comparing, that the second OS is a more current version of the first OS; in response to the determining that the second OS is a more current version of the first OS, moving, in conjunction with live application mobility, a virtual machine (VM) workload partition (WPAR) on the first LPAR to a second LPAR, the moving comprising determining a set of overlays associated with the WPAR corresponding to the second OS; removing from the WPAR any overlays associated with the first OS; applying to the WPAR a set of overlays corresponding to the second OS; check pointing processes associated with the WPAR; and copying live data associated with the LPAR from the first LPAR to the second LPAR.

A symbol resolution unit can be configured for resolving conflicting operating system symbols. A default symbol resolution data structure can be accessed to resolve a symbol associated with a client of an operating system. A first data entry that corresponds to the symbol is located in the default symbol resolution data structure. It is determined that the first data entry indicates that the symbol is marked special (e.g., as a conflicting operating system symbol). A secondary symbol resolution data structure is accessed in response to determining that the first data entry indicates that the symbol is marked special. A second data entry that corresponds to the symbol is located in the secondary symbol resolution data structure based, at least in part, on an identifier of the client. A memory location indicated in the second data entry that corresponds to the symbol is provided to the client.

Minimizing overhead in resolving operating system symbols

A kernel extension associated with a first instance of an operating system can be detected. The kernel extension is configured to extend functionality of the kernel when loaded in a kernel managed by a second instance of the operating system. Some embodiments are further directed to detecting symbols for the kernel extension, where the symbols specify one or more functions associated with the kernel extension. Some embodiments are further directed to generating a first namespace that is assigned only to the first of the plurality of instances of the operating system. The first namespace is separate from a second namespace for the second of the plurality of the instances of the operating system. Some embodiments are further directed to storing the symbols in the first namespace.

Controlling kernel symbol visibility and accessibility across operating system linkage spaces

An approach is provided in preparing a dynamically loaded kernel extension. The approach includes compiling a kernel extension program that includes a symbol, such as a function. The symbol is exported from the kernel extension program and a symbol broker that references the exported symbol is compiled. A kernel extension loader library is created with a defined callable symbol that corresponds to the exported symbol. The kernel extension loader library is linked by an external program after compilation of the external program resulting in a compiled external program. The kernel extension loader library dynamically loads the compiled kernel extension program, the compiled symbol broker, and the exported symbol when the defined callable symbol is referenced by during execution of the compiled external program.

Dynamic loading of kernel extensions

A method includes atomically reading a next field of a current element of the linked list to determine a first value that encodes a first pointer to the first element and a first indication of an owner of the first element. The first indication of the owner is stored in a first of a plurality of multi-field reservation data structures. The operation includes determining whether the next field of the current element still indicates the first value. The operation includes reading the first element of the linked list via the first pointer if the next field of the current element still indicates the first value. If the next field of the current element indicates a current value different than the first value, the first indication of the owner is removed from the first multi-field reservation data structure, and storing and determining with the second value is repeated.

Maintenance and access of a linked list

Methods and arrangements of representing the allocation of integers are discussed. Embodiments include transformations, code, state machines or other logic to represent the allocation of integers. An embodiment may involve representing a first allocation of integers via a set of nodes of a tree. In the representation, a data structure in a node may represent, for each integer in a set of integers, whether the integer is allocated or free. The embodiment may also involve representing a subsequent allocation. The representing may include adding a new node to the nodes of the tree for the first allocation. The subsequent allocation may consist of freeing of an integer allocated in the first allocation. The data structure of the new node may represent that the integer is free.

Representing the allocation of integers

A process for managing customizations for components in a component tree includes for each customization associated with the parent of a component, matching the pathname of the component with the customization path. The process further includes associating the customization with the component, if the matching results in a partial match. The process further includes applying the customization to the component, if the matching results in a complete match.

Applying persistence to selected attributes of static and dynamic operating system components

A computer implemented method, computer program product, and computer usable program code for preventing execution of program components having errors. First, a software application is executed. The software application interacts with a number of programs. Next, an error message is received. The error message indicates an error has occurred in a first program within the number of programs. The first program is then isolated such that the first program no longer interacts with the software application.

Method of isolating erroneous software program components

A method and apparatus for managing data structures associated with large files are provided. With the apparatus and method, region control blocks for a data file are allocated on demand from an array of control blocks and are organized into a tree data structure. The tree data structure includes a base region control block and zero or more extended region control blocks. The base region control block includes a pointer to a root of the tree data structure and information about the data file. The extended region control blocks have pointers to the base region control block, to a successor region control block, and pointers to zero to four child region control blocks. Using this tree data structure, the operating system may perform various operations on the region control blocks with improved performance.

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Austin, TX, United States of America

Stephen Bailey Peckham