13 Commits

Author SHA1 Message Date
Gregory Nutt
c9ca97b4b5 cancellation points are basically function. More tested is needed and additional cancellation points must be implemented before this can be merged back to master. 2016-12-09 12:01:18 -06:00
Gregory Nutt
018db84567 Flesh out more cancellation point logic. 2016-12-09 10:31:40 -06:00
Freddie Chopin
484a1b6104 sem_wait() and sem_trywait() no longer modify the errno value UNLESS an error occurs. This allows these functions to be used internallly without clobbering the errno value. 2016-11-09 07:01:49 -06:00
Gregory Nutt
3e13ed2400 Within the OS, when a thread obtains a semaphore count it must call sem_addholder() if CONFIG_PRIORITY_INHERITANCE is enabled. If a count is available, then sem_wait() calls sem_addholder(), otherwise it waited for the semaphore and called sem_addholder() when it eventually received the count.
This caused a problem when the thread calling sem_wait() was very low priority.  When it received the count, there may be higher priority threads "hogging" the CPU that prevent the lower priority task from running and, as a result, the sem_addholder() may be delayed indefinitely.

The fix was to have sem_post() call sem_addholder() just before restarting the thread waiting for the semaphore count.

This problem was noted by Benix Vincent who also suggested the solution.
2016-10-26 07:23:15 -06:00
Paul A. Patience
891113dac9 sched/semaphore: Fix setting EINVAL in sem_post() and sem_wait() 2016-06-28 10:15:52 -04:00
Gregory Nutt
6e3107650d nuttx/sched: Replace irqsave() with enter_critical_section(); replace irqrestore() with leave_critical_section() 2016-02-14 08:17:46 -06:00
Gregory Nutt
74db48202e sched/: Replace explict references to g_readytorun with indirect references via the this_task() macro 2016-02-06 17:44:41 -06:00
Gregory Nutt
b90da3f27b waitpid: CRITICAL BUGFIX. Add a reference counting mechansim to prevent wait from using stale memory that was freed by the exiting task 2015-12-22 11:48:17 -06:00
Gregory Nutt
79d554939e sched/: Fix some spacing issues 2015-10-07 19:59:14 -06:00
Gregory Nutt
cb9e27c3b0 Standardize naming used for public data and function groupings 2015-10-02 16:30:35 -06:00
Gregory Nutt
093a144934 sem_wait(): Missing comma on debug statement caused compile error with DEBUG on. Why hasn't that been noted before? 2015-04-23 07:15:55 -06:00
Gregory Nutt
d798dd37a7 Replace os_internal.h with sched/sched.h in files that actually reference something in sched.h 2014-08-08 17:53:55 -06:00
Gregory Nutt
e10a23ae50 Move environment files from sched/ to sched/environ 2014-08-08 13:53:29 -06:00