Operating System With A Single Kernel Stack Per Processor

Abstract

In one embodiment, a method includes storing thread state information associated with the first user-mode thread into a memory space associated with the first user-mode thread when executing in kernel space in response to a first system call by a first-user mode thread, executing first operations corresponding to the first system call on a processor, where data associated with executing the first operations are stored on a kernel stack associated with the processor, determining to pause the execution of the first operations, enqueuing a workload on a schedule queue for resuming execution of the first operations in a future, where the workload comprises data associated with executing a remainder of the first operations, and executing second operations corresponding to a second system call from a second user-mode thread on the processor, where data associated with executing the second operations are stored on the kernel stack associated with the processor.

1 - 20 . (canceled) 
     
     
         21 . A method comprising, by a kernel-mode thread of an operating system of a computing device:
 executing first operations corresponding to a first system call, wherein data associated with executing the first operations are stored on a kernel stack associated with a processor;   determining to pause the execution of the first operations;   enqueuing a workload on a schedule queue for resuming the execution of the first operations in a future, wherein the workload comprises data associated with executing a remainder of the first operations; and   executing second operations corresponding to a second system call, wherein data associated with executing the second operations are stored on the kernel stack associated with the processor.   
     
     
         22 . The method of  claim 21 , wherein a processor of the computing device is associated with only one kernel-mode thread. 
     
     
         23 . The method of  claim 22 , wherein the first operations and the second operations are executed by the kernel-mode thread running on the processor. 
     
     
         24 . The method of  claim 21 , wherein determining to pause the execution of the first operations comprises calling a scheduler function, wherein the scheduler function makes a schedule decision among a plurality of workloads in the schedule queue. 
     
     
         25 . The method of  claim 24 , wherein the schedule decision is made based on one or more scheduling policies. 
     
     
         26 . The method of  claim 21 , wherein the operating system is a microkernel-based operating system, wherein user-mode threads in the operating system comprise user application threads and service-providing threads. 
     
     
         27 . The method of  claim 26 , wherein a first service-providing thread provides a particular service to one or more user-mode threads. 
     
     
         28 . The method of  claim 27 , wherein a request for the particular service from one of the one or more user-mode threads to the first service-providing thread is communicated through one of available Inter-Process Communication (IPC) mechanisms. 
     
     
         29 . The method of  claim 28 , wherein a result of the particular service from the first service-providing thread to the one of the one or more user-mode threads is communicated through one of the available IPC mechanisms or a shared memory. 
     
     
         30 . The method of  claim 26 , wherein the service-providing threads comprise device drivers. 
     
     
         31 . The method of  claim 26 , wherein the user application threads are implemented with an event-driven architecture. 
     
     
         32 . The method of  claim 21 , wherein the first system call is made by a first user-mode thread, wherein thread state information associated with the first user-mode thread is stored into a memory space associated with the first user-mode thread before the first operations are executed, and wherein the thread state information associated with the first user-mode thread is a snapshot of register values associated with the processor when the first user-mode thread makes the first system call. 
     
     
         33 . The method of  claim 32 , wherein the memory space associated with the first user-mode thread is a Thread-Local Storage (TLS) associated with the first user-mode thread or a Thread Control Block (TCB) associated with the first user-mode thread. 
     
     
         34 . The method of  claim 21 , wherein the second system call is made by a second user-mode thread, and wherein the second operations comprise returning to the second user-mode thread. 
     
     
         35 . The method of  claim 34 , wherein returning to the second user-mode thread comprises:
 retrieving thread state information associated with the second user-mode thread from a memory space associated with the second user-mode thread;   returning results of the second operations to the second system call; and   restoring registers of the processor with the retrieved thread state information.   
     
     
         36 . One or more computer-readable non-transitory storage media embodying software that is operable by a kernel-mode thread of an operating system of a computing device when executed to:
 execute first operations corresponding to a first system call, wherein data associated with executing the first operations are stored on a kernel stack associated with a processor;   determine to pause the execution of the first operations;   enqueue a workload on a schedule queue for resuming the execution of the first operations in a future, wherein the workload comprises data associated with executing a remainder of the first operations; and   execute second operations corresponding to a second system call, wherein data associated with executing the second operations are stored on the kernel stack associated with the processor.   
     
     
         37 . The media of  claim 36 , wherein a processor of the computing device is associated with only one kernel-mode thread. 
     
     
         38 . The media of  claim 37 , wherein the first operations and the second operations are executed by the kernel-mode thread running on the processor. 
     
     
         39 . The media of  claim 36 , wherein determining to pause the execution of the first operations comprises calling a scheduler function, wherein the scheduler function makes a schedule decision among a plurality of workloads in the schedule queue. 
     
     
         40 . A computing device comprising:
 one or more processors; and   one or more computer-readable non-transitory storage media coupled to one or more of the one or more processors and comprising instructions operable when executed by one of the one or more processors to cause a kernel-mode thread of an operating system of the computing device to:
 execute first operations corresponding to a first system call, wherein data associated with executing the first operations are stored on a kernel stack associated with a processor among the one or more processors; 
 determine to pause the execution of the first operations; 
 enqueue a workload on a schedule queue for resuming the execution of the first operations in a future, wherein the workload comprises data associated with executing a remainder of the first operations; and 
 execute second operations corresponding to a second system call, wherein data associated with executing the second operations are stored on the kernel stack associated with the processor.