19012b786e
Running locktorture scenario LOCK05 results in hangs: tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --torture lock --duration 3 --configs LOCK05 The lock_torture_writer() kthreads set themselves to MAX_NICE while running SCHED_OTHER. Other locktorture kthreads run at default niceness, also SCHED_OTHER. This results in these other locktorture kthreads indefinitely preempting the lock_torture_writer() kthreads. Note that the cond_resched() in the stutter_wait() function's loop is ineffective because this scenario is built with CONFIG_PREEMPT=y. It is not clear that such indefinite preemption is supposed to happen, but in the meantime this commit prevents kthreads running in stutter_wait() from being completely CPU-bound, thus allowing the other threads to get some CPU in a timely fashion. This commit also uses hrtimers to provide very short sleeps to avoid degrading the sudden-on testing that stutter is supposed to provide. Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Linux kernel
============
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.
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.