source: trunk/kernel/kern/scheduler.h @ 296

Last change on this file since 296 was 296, checked in by alain, 4 years ago

Several modifs in the generic scheduler and in the hal_context to
fix the context switch mechanism.

File size: 7.0 KB
Line 
1/*
2 * scheduler.h - Core scheduler definition.
3 *
4 * Author    Alain Greiner (2016)
5 *
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#ifndef _SCHEDULER_H_
25#define _SCHEDULER_H_
26
27#include <hal_types.h>
28#include <list.h>
29#include <spinlock.h>
30
31/****  Forward declarations  ****/
32
33struct core_s;
34struct thread_s;
35
36/*********************************************************************************************
37 * This structure define the scheduler associated to a given core.
38 ********************************************************************************************/
39
40typedef struct scheduler_s
41{
42    spinlock_t        lock;         /*! readlock protecting lists of threads                */
43    uint16_t          u_threads_nr; /*! total numbre of attached user threads               */
44    uint16_t          k_threads_nr; /*! total number of attached kernel threads             */
45    list_entry_t      u_root;       /*! root of list of user threads for this scheduler     */
46    list_entry_t      k_root;       /*! root of list of kernel threads for this scheduler   */
47    list_entry_t    * u_last;       /*! pointer on list_entry for last executed k_thread    */
48    list_entry_t    * k_last;       /*! pointer on list entry for last executed u_thread    */
49    struct thread_s * idle;         /*! pointer on idle thread                              */
50    struct thread_s * current;      /*! pointer on current running thread                   */
51}
52scheduler_t;
53
54/*********************************************************************************************
55 *  This function initialises the scheduler for a given core.
56 ********************************************************************************************/ 
57void sched_init( struct core_s * core );
58
59/*********************************************************************************************
60 * This function register a new thread in a given core scheduler.
61 *********************************************************************************************
62 * @ core    : local pointer on the core descriptor.
63 * @ thread  : local pointer on the thread descriptor.
64 ********************************************************************************************/ 
65void sched_register_thread( struct core_s   * core,
66                            struct thread_s * thread );
67
68/*********************************************************************************************
69 *  This function removes a thread from the set of threads attached to a given core.
70 *********************************************************************************************
71 * @ thread  : local pointer on the thread descriptor.
72 ********************************************************************************************/ 
73void sched_remove_thread( struct thread_s * thread );
74
75/*********************************************************************************************
76 * This function handles pending signals for all registered threads, and tries to make
77 * a context switch for the core running the calling thread.
78 * - If the <next> argument is not NULL, this next thread starts execution.
79 * - If <next> is NULL, it calls the sched_select() function. If there is a runable thread
80 *   (other than current thread or idle thread), this selected thread starts execution.
81 * - If there is no other runable thread, the calling thread continues execution.
82 * - If there is no runable thread, the idle thread is executed.
83 *********************************************************************************************
84 * @ next  : local pointer on next thread to run / call sched_select() if NULL.
85 ********************************************************************************************/
86void sched_yield( struct thread_s * next );
87
88/*********************************************************************************************
89 * This function scan all threads attached to a given core scheduler, and executes
90 * the relevant actions for pending signals, such as the THREAD_SIG_KILL signal.
91 *********************************************************************************************
92 * @ core    : local pointer on the core descriptor.
93 ********************************************************************************************/
94void sched_handle_signals( struct core_s * core );
95
96/*********************************************************************************************
97 * This function is used by the scheduler of a given core to actually kill a thread that has
98 * the SIG_KILL signal set (following a thread_exit() or a thread_kill() event).
99 * - It checks that the thread has released all locks => panic otherwise...
100 * - It detach the thread from the local process descriptor.
101 * - It removes the thread from the scheduler.
102 * - It release physical memory allocated for thread descriptor.
103 *********************************************************************************************
104 * @ thread  : local pointer on the thread descriptor.
105 ********************************************************************************************/
106void sched_kill_thread( struct thread_s * thread );
107
108/*********************************************************************************************
109 * This function does NOT modify the scheduler state.
110 * It just select a thread in the list of attached threads, implementing the following policy:
111 * 1) it scan the list of kernel threads, from the next thread after the last executed one,
112 *    and returns the first runnable found (can be the current thread).
113 * 2) if no kernel thread found, it scan the list of user thread, from the next thread after
114 *    the last executed one, and returns the first runable found (can be the current thread).
115 * 3) if no runable thread found, it returns the idle thread.
116 *********************************************************************************************
117 * @ core    : local pointer on the core descriptor.
118 * @ returns pointer on selected thread descriptor
119 ********************************************************************************************/
120struct thread_s * sched_select( struct core_s * core );
121
122/*********************************************************************************************
123 * This function display the internal state of the calling core scheduler.
124 ********************************************************************************************/
125void sched_display();
126
127
128#endif  /* _SCHEDULER_H_ */
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