Blackberry Corporation

Elad Lahav

Peter H Van Der Veen

Danny Thomas Dodge

In some examples, a system includes a kernel scheduler to schedule, for execution, threads to run in an address space of an operating system (OS) kernel according to respective priorities associated with the threads, where each thread of the threads has a user persona and a kernel persona. The kernel scheduler switches each respective thread of the threads to the kernel persona of the respective thread in response to scheduling the respective thread for execution responsive to a kernel call from the respective thread. The kernel scheduler preempts a thread in the kernel persona of the thread that is actively executing in response to an event.

Thread scheduling including preemption of a thread in a kernel persona

In some examples, a system includes a plurality of processors and a kernel scheduler. The kernel scheduler associates each respective processor of the plurality of processors with a collection of clusters, wherein each cluster of the collection of clusters represents a respective different subset of the plurality of processors, and the respective processor is a member of each cluster of the collection of clusters. For each corresponding cluster of the collection of clusters, the kernel scheduler maintains a data structure associated with a ready queue of the kernel scheduler, the data structure comprising elements representing thread priorities, wherein an element of the data structure is associated with an ordered list of threads in the ready queue.

Scheduling of threads for clusters of processors

In some examples, a system includes an operating system (OS) kernel, one or more hardware processors, and a kernel scheduler. The kernel scheduler receives a first indication that a first thread is to wait for an event, receives a second indication that the first thread has transitioned to a blocked state in which the first thread is blocked on the event, and receives a third indication from a second thread delivering the event, the third indication to unblock the first thread. In response to the third indication, the kernel scheduler causes a transition of the first thread from the wait state to an active state if the first thread is in the wait state and has not yet transitioned to the blocked state, and causes a transition of the first thread from the blocked state to a ready state if the first thread is in the blocked state.

Thread state transitions

In some examples, a system includes one or more hardware processors, an interrupt service thread to handle an interrupt, and a kernel scheduler to schedule the interrupt service thread as part of a collection of threads to be scheduled.

Interrupt handling

A system and method enforce file system path-based access controls in a message-based operating system. The system and method enforce a list of rules that provide a grant and an access restriction to file system paths to server applications. A path manager receives client messages marked by a kernel to indicate that the client is subject to the path-based access controls. The path manager control access to the file systems served by the server applications in response to the rules that provide grants and access restrictions. The path manager exercises that control by transmitting messages to the client that establishes privileges to systems paths through an authentication protocol.

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Stittsville, Canada

Elad Lahav