rbraun/x15.git - The X15 microkernel

Age	Commit message (Collapse)	Author
2019-01-10	kern/semaphore: rework	Richard Braun
	The previous implementation, which uses a combination of fast and slow paths around accessing an atomic integer, suffers from a bug triggered when two or more posts are performed back-to-back, without a waiter decrementing the semaphore value in between. The first post would be the only one signalling a waiter. In addition, having a fast path that expects the absence of waiters probably doesn't make sense, as semaphores are expected to be used for signalling threads. As a result, it was decided to remove the fast path altogether, and protect the semaphore value with sleep queues. Finally, as part of the rework, semaphores now have a user-defined maximum value, in order to make the implementation of, e.g. wrappers for binary semaphores, convenient. Thanks to Simon Venken for reporting the bug.
2018-04-19	kern/atomic: remove shortcuts	Richard Braun
	These shortcuts just don't bring enough value.
2018-02-24	Don't use reserved identifiers	Richard Braun

2017-09-07	kern/semaphore: add missing atomic access	Richard Braun

2017-08-27	kern/semaphore: implement timed waits	Richard Braun

2017-05-30	Move assert.h to the include directory	Richard Braun
	This turns assert.h into a standard header.
2017-05-09	Replace sequential consistency with more efficient orders	Agustina Arzille

2017-04-04	Use the new atomic operations interface	Agustina Arzille
	Stick to a sequentially consistent model for most atomic operations as it matches the semantics of the existing code. Each call site will have to be reevaluated in order to switch to more relaxed accesses where possible.
2017-03-17	kern/semaphore: new module	Richard Braun