source: trunk/kernel/kern/scheduler.h @ 564

Last change on this file since 564 was 564, checked in by alain, 3 years ago

Complete restructuration of kernel locks.

File size: 5.9 KB
Line 
1/*
2 * scheduler.h - Core scheduler definition.
3 *
4 * Author    Alain Greiner (2016,2017,2018)
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_kernel_types.h>
28#include <list.h>
29#include <busylock.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    busylock_t        lock;            /*! lock protecting scheduler state                  */
43    uint16_t          u_threads_nr;    /*! total number 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                     */
46    list_entry_t      k_root;          /*! root of list of kernel threads                   */
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    volatile bool_t   req_ack_pending; /*! sequencialize ack requests when true             */
52    bool_t            trace;           /*! context switches trace activated if true         */
53}
54scheduler_t;
55
56/*********************************************************************************************
57 *  This function initialises the scheduler for a given core.
58 ********************************************************************************************/ 
59void sched_init( struct core_s * core );
60
61/*********************************************************************************************
62 * This function atomically register a new thread in a given core scheduler.
63 * Note: There is no specific sched_remove_thread(), as a thread is always deleted
64 * by the ched_handle_signals() function, called by the sched_yield() function.
65 *********************************************************************************************
66 * @ core    : local pointer on the core descriptor.
67 * @ thread  : local pointer on the thread descriptor.
68 ********************************************************************************************/ 
69void sched_register_thread( struct core_s   * core,
70                            struct thread_s * thread );
71
72/*********************************************************************************************
73 * This function is the only method to make a context switch. It is called in cas of TICK,
74 * or when a thread explicitely requires to be descheduled.
75 * It takes the scheduler busylock to atomically update the scheduled state.
76 * It calls the sched_select() private function to select a new thread. After switch, it
77 * calls the sched_handle_signals() private function to handle the pending REQ_ACK and
78 * REQ_DELETE flagss for all threads attached to the scheduler: it deletes all threads
79 * marked for delete (and the process descriptor when the deleted thread is the main thread).
80 * As the REQ_DELETE flag can be asynchronously set (between the select and the handle),
81 * the sched_handle-signals() function check that the thread to delete is not the new thread,
82 * because a thread cannot delete itself.
83 * The cause argument is only used for debug by the sched_display() functions, and indicates
84 * the scheduling cause.
85 *********************************************************************************************
86 * @ cause    : character string defining the scheduling cause.
87 ********************************************************************************************/
88void sched_yield( const char * cause );
89
90/*********************************************************************************************
91 * This debug function displays on TXT0 the internal state of a local scheduler,
92 * identified by the core local index <lid>. It must be called by a local thread.
93 *********************************************************************************************
94 * @ lid      : local index of target core.
95 ********************************************************************************************/
96void sched_display( lid_t lid );
97
98/*********************************************************************************************
99 * This debug function displays on TXT0 the internal state of a scheduler,
100 * identified by the target cluster identifier <cxy> and the core local index <lid>.
101 * It can be called by a thread running in any cluster, as it uses remote accesses,
102 * to scan the scheduler lists of threads.
103 *********************************************************************************************
104 * @ cxy      : target cluster identifier
105 * @ lid      : local index of target core.
106 ********************************************************************************************/
107void sched_remote_display( cxy_t  cxy,
108                           lid_t  lid );
109
110#endif  /* _SCHEDULER_H_ */
Note: See TracBrowser for help on using the repository browser.