Implemented a new system call cpu_block() to block all task from running for specified length except itself and tasks with rt priority high than 50 (kernel threads). It is implemented using a hrtimer that has the period specified in the calling process's cgroup cpu.window_us. The syscall has a syscall number of 400 and no input parameters. You can invoke it using syscall(400).
Add a parameter window_us for cgroup to specify the blocking time in microseconds. To set the parameter
echo time_in_us > /sys/fs/cgroup/cpu/cg/cg1/cpu.window_us
- note: The blocking function will not work unless this parameter is set.
Some cgroup setup scripts and test programs are in the folder tools/exp/.
Important: If the window is too long compared with the period of the invoking task, the whole system might become unresponsive.
There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first.
In order to build the documentation, use make htmldocs or
make pdfdocs. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.