System and method for hybrid kernel and user-space checkpointing using a character device

Inventors

Havemose, Allan

Assignees

Philips North America LLC

Abstract

A system, method, and computer readable medium for hybrid kernel-mode and user-mode checkpointing of multi-process applications using a character device. The computer readable medium includes computer-executable instructions for execution by a processing system. A multi-process application runs on primary hosts and is checkpointed by a checkpointer comprised of a kernel-mode checkpointer module and one or more user-space interceptors providing barrier synchronization, checkpointing thread, resource flushing, and an application virtualization space. Checkpoints may be written to storage and the application restored from said stored checkpoint at a later time. Checkpointing is transparent to the application and requires no modification to the application, operating system, networking stack or libraries. In an alternate embodiment the kernel-mode checkpointer is built into the kernel.

Core Innovation

The invention provides a hybrid kernel-mode and user-space checkpointing approach for multi-process applications. A kernel module performs transparent checkpoint capture by capturing memory-page and kernel-state information during application execution, while user-space interceptors coordinate execution and checkpoint behavior through barrier synchronization and other controls.

A character-device checkpointer interface is used for checkpoint creation, including a read function that includes memory pages used by the applications. The checkpointer reads memory locations and creates checkpoints by capturing the memory pages, and the captured kernel state and memory information are used to write checkpoint data to storage for later restore.

An Application Virtualization Space (AVS) virtualizes operating system constructs such as PIDs, TIDs, and resource identities across restore. During restore, the initial process recreates the process hierarchy and remaps the AVS resources so that checkpointed applications, including shared/global state and process relationships, are restored while maintaining transparent operation without modifying the application, OS, networking stack, or libraries.

Claims Coverage

This patent contains four independent claims, centered on synchronization points that coordinate or pause application execution and a checkpointer that creates checkpoints by reading memory pages used by the applications, with a character-device implementation and specific read-function behaviors.

Across the independent claims, the core claim coverage is the combination of a synchronization point that coordinates and/or pauses application execution with a checkpointer that creates checkpoints by reading memory pages used by the applications, implemented as or accessed via a character-device read function that includes a read-function mechanism for forwarding a device pointer to a next page after a read.

Stated Advantages

Documented Applications