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kernel: New timeout implementation

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Now that the API has been fixed up, replace the existing timeout queue
with a much smaller version.  The basic algorithm is unchanged:
timeouts are stored in a sorted dlist with each node nolding a delta
time from the previous node in the list; the announce call just walks
this list pulling off the heads as needed.  Advantages:

* Properly spinlocked and SMP-aware.  The earlier timer implementation
  relied on only CPU 0 doing timeout work, and on an irq_lock() being
  taken before entry (something that was violated in a few spots).
  Now any CPU can wake up for an event (or all of them) and everything
  works correctly.

* The *_thread_timeout() API is now expressible as a clean wrapping
  (just one liners) around the lower-level interface based on function
  pointer callbacks.  As a result the timeout objects no longer need
  to store backpointers to the thread and wait_q and have shrunk by
  33%.

* MUCH smaller, to the tune of hundreds of lines of code removed.

* Future proof, in that all operations on the queue are now fronted by
  just two entry points (_add_timeout() and z_clock_announce()) which
  can easily be augmented with fancier data structures.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
This commit is contained in:
Andy Ross 2018-09-27 16:50:00 -07:00 • committed by Anas Nashif
commit 987c0e5fc1
11 changed files with 315 additions and 637 deletions
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17
include/sys_clock.h
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@ -199,14 +199,10 @@ u32_t z_tick_get_32(void);
*/
s64_t z_tick_get(void);
/**
*
* @brief Sets the current system tick count
*
* @param ticks Ticks since system start
*
*/
void z_tick_set(s64_t ticks);
#ifndef CONFIG_SYS_CLOCK_EXISTS
#define z_tick_get() (0)
#define z_tick_get_32() (0)
#endif
/* timeouts */
@ -215,9 +211,8 @@ typedef void (*_timeout_func_t)(struct _timeout *t);
struct _timeout {
sys_dnode_t node;
struct k_thread *thread;
s32_t delta_ticks_from_prev;
_timeout_func_t func;
s32_t dticks;
_timeout_func_t fn;
};
/*