source: trunk/kernel/kern/scheduler.h @ 411

Last change on this file since 411 was 409, checked in by alain, 6 years ago

Fix bugs in exec
File size: 7.4 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    bool_t            sig_pending;  /*! signal_handller must be called when true            */
52}
53scheduler_t;
54
55/*********************************************************************************************
56 *  This function initialises the scheduler for a given core.
57 ********************************************************************************************/ 
58void sched_init( struct core_s * core );
59
60/*********************************************************************************************
61 * This function register a new thread in a given core scheduler.
62 *********************************************************************************************
63 * @ core    : local pointer on the core descriptor.
64 * @ thread  : local pointer on the thread descriptor.
65 ********************************************************************************************/ 
66void sched_register_thread( struct core_s   * core,
67                            struct thread_s * thread );
68
69/*********************************************************************************************
70 * This function remove a thread from its scheduler.re scheduler.
71 *********************************************************************************************
72 * @ thread  : local pointer on the thread descriptor.
73 ********************************************************************************************/ 
74void sched_remove_thread( struct thread_s * thread );
75
76/*********************************************************************************************
77 * This function is the only method to make a context switch. It is called in cas of TICK,
78 * or when when a thread explicitely requires a scheduling.
79 * It handles the pending signals for all threads attached to the core running the calling
80 * thread, and calls the sched_select() function to select a new thread.
81 * The cause argument is only used for debug by the sched_display() function, and
82 * indicates the scheduling cause.
83 *********************************************************************************************
84 * @ cause    : character string defining the scheduling cause.
85 ********************************************************************************************/
86void sched_yield( char * cause );
87
88/*********************************************************************************************
89 * This function scan all threads attached to a given core scheduler, and executes
90 * the relevant actions for pending KILL or EXIT signals.
91 * It is called in by the sched_yield() function, with IRQ disabled.
92 *********************************************************************************************
93 * @ core    : local pointer on the core descriptor.
94 ********************************************************************************************/
95void sched_handle_signals( struct core_s * core );
96
97/*********************************************************************************************
98 * This function does NOT modify the scheduler state.
99 * It just select a thread in the list of attached threads, implementing the following
100 * three steps policy:
101 * 1) It scan the list of kernel threads, from the next thread after the last executed one,
102 *    and returns the first runnable found : not IDLE, not blocked, client queue not empty.
103 *    It can be the current thread.
104 * 2) If no kernel thread found, it scan the list of user thread, from the next thread after
105 *    the last executed one, and returns the first runable found : not blocked.
106 *    It can be the current thread.
107 * 3) If no runable thread found, it returns the idle thread.
108 *********************************************************************************************
109 * @ core    : local pointer on scheduler.
110 * @ returns pointer on selected thread descriptor
111 ********************************************************************************************/
112struct thread_s * sched_select( struct scheduler_s * sched );
113
114/*********************************************************************************************
115 * This function unlink a thread identified by the <thread> pointer from its process.
116 * It is called by the sched_handle_signals() function when one EXIT or KILL signal is set,
117 * and it implement the first step of a thread destructionebut can also be directly called by a local killer thread signal.
118 * - It detach the thread from the scheduler.
119 * - It detach the thread from the process.
120 * - It detach the thread from the parent thread when the thread is attached.
121 * - It destroys the thread descriptor.
122 * - It acknowledge the killer thread if it's a kill signal
123 *********************************************************************************************
124 * @ thread   : pointer on thread to be killed.
125 ********************************************************************************************/
126void sched_kill_thread( struct thread_s * thread );
127
128/*********************************************************************************************
129 * This function display the internal state of the local core identified by its <lid>.
130 *********************************************************************************************
131 * @ lid      : local index of target core.
132 ********************************************************************************************/
133void sched_display( lid_t lid );
134
135
136#endif  /* _SCHEDULER_H_ */
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