1 /* a fast and simple context switching library */
3 /* Copyright (c) 2004-2008 the SimGrid team. */
4 /* All rights reserved. */
6 /* This program is free software; you can redistribute it and/or modify it
7 * under the terms of the license (GNU LGPL) which comes with this package. */
12 #include "smx_context_private.h"
14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(smx_context, simix, "Context switching mecanism");
16 /* the context factory used to create the appropriate context
17 * each context implementation define its own context factory
18 * a context factory is responsable of the creation of the context
19 * associated with the maestro and of all the context based on
20 * the selected implementation.
22 * for example, the context switch based on java thread use the
23 * java implementation of the context and the java factory build
24 * the context depending of this implementation.
28 * This function is call by SIMIX_global_init() to initialize the context module.
30 void SIMIX_context_mod_init(void)
32 if (!simix_global->context_factory) {
33 /* select context factory to use to create the context(depends of the macro definitions) */
35 #ifdef CONTEXT_THREADS
36 /* context switch based os thread */
37 SIMIX_ctx_thread_factory_init(&simix_global->context_factory);
39 /* context switch based ucontext */
40 SIMIX_ctx_sysv_factory_init(&simix_global->context_factory);
42 /* context switch is not allowed on Windows */
43 #error ERROR [__FILE__, line __LINE__]: no context based implementation specified.
49 * This function is call by SIMIX_clean() to finalize the context module.
51 void SIMIX_context_mod_exit(void)
53 if (simix_global->context_factory) {
54 smx_pfn_context_factory_finalize_t finalize_factory;
56 /* if there are living processes then kill them (except maestro) */
57 if(simix_global->process_list != NULL)
58 SIMIX_process_killall();
60 /* finalize the context factory */
61 finalize_factory = simix_global->context_factory->finalize;
62 (*finalize_factory) (&simix_global->context_factory);
66 /*******************************/
67 /* Object creation/destruction */
68 /*******************************/
70 * \param smx_process the simix process that contains this context
71 * \param code a main function
73 int SIMIX_context_new(smx_process_t *process, xbt_main_func_t code)
75 /* use the appropriate context factory to create the appropriate context */
76 return (*(simix_global->context_factory->create_context)) (process, code);
80 int SIMIX_context_create_maestro(smx_process_t *process)
82 return (*(simix_global->context_factory->create_maestro_context)) (process);
85 /* Scenario for the end of a context:
87 * CASE 1: death after end of function
88 * __context_wrapper, called by os thread, calls smx_context_stop after user code stops
89 * smx_context_stop calls user cleanup_func if any (in context settings),
90 * add current to trashbin
91 * yields back to maestro (destroy os thread on need)
92 * From time to time, maestro calls smx_context_empty_trash,
93 * which maps smx_context_free on the content
94 * smx_context_free frees some more memory,
97 * CASE 2: brutal death
98 * smx_context_kill (from any context)
99 * set context->wannadie to 1
100 * yields to the context
101 * the context is awaken in the middle of __yield.
102 * At the end of it, it checks that wannadie == 1, and call smx_context_stop
103 * (same than first case afterward)
107 /* Argument must be stopped first -- runs in maestro context */
108 void SIMIX_context_free(smx_process_t process)
110 (*(simix_global->context_factory->free)) (process);
113 void SIMIX_context_kill(smx_process_t process)
115 (*(simix_global->context_factory->kill)) (process);
119 * \param context the context to start
121 * Calling this function prepares \a process to be run. It will
122 however run effectively only when calling #SIMIX_context_schedule
124 void SIMIX_context_start(smx_process_t process)
126 (*(simix_global->context_factory->start)) (process);
130 * Calling this function makes the current process yield. The process
131 * that scheduled it returns from SIMIX_context_schedule as if nothing
134 * Only the processes can call this function, giving back the control
137 void SIMIX_context_yield(void)
139 (*(simix_global->context_factory->yield)) ();
143 * \param process to be scheduled
145 * Calling this function blocks the current process and schedule \a process.
146 * When \a process would call SIMIX_context_yield, it will return
147 * to this function as if nothing had happened.
149 * Only the maestro can call this function to run a given process.
151 void SIMIX_context_schedule(smx_process_t process)
153 (*(simix_global->context_factory->schedule)) (process);
156 void SIMIX_context_stop(int exit_code)
158 (*(simix_global->context_factory->stop)) (exit_code);
161 int SIMIX_context_select_factory(const char *name)
163 /* if a factory is already instantiated (SIMIX_context_mod_init() was called) */
164 if (simix_global->context_factory != NULL) {
165 /* if the desired factory is different of the current factory, call SIMIX_context_mod_exit() */
166 if (strcmp(simix_global->context_factory->name, name))
167 SIMIX_context_mod_exit();
169 /* the same context factory is requested return directly */
173 /* get the desired factory */
174 SIMIX_context_init_factory_by_name(&simix_global->context_factory, name);
176 /* maestro process specialisation */
177 (*(simix_global->context_factory->create_maestro_context)) (&simix_global->maestro_process);
179 /* the current process is the process of the maestro */
180 simix_global->current_process = simix_global->maestro_process;
182 /* the current context doesn't want to die */
183 simix_global->current_process->iwannadie = 0;
185 /* insert the current context in the list of the contexts in use */
186 xbt_swag_insert(simix_global->current_process, simix_global->process_list);
192 SIMIX_context_init_factory_by_name(smx_context_factory_t * factory,
195 if (!strcmp(name, "java"))
197 SIMIX_ctx_java_factory_init(factory);
199 THROW0(not_found_error, 0, "Factory 'Java' does not exist: Java support was not compiled in the SimGrid library");
200 #endif /* HAVE_JAVA */
202 else if (!strcmp(name, "thread"))
203 #ifdef CONTEXT_THREADS
204 SIMIX_ctx_thread_factory_init(factory);
206 THROW0(not_found_error, 0, "Factory 'thread' does not exist: thread support was not compiled in the SimGrid library");
207 #endif /* CONTEXT_THREADS */
209 else if (!strcmp(name, "sysv"))
210 #if !defined(WIN32) && !defined(CONTEXT_THREADS)
211 SIMIX_ctx_sysv_factory_init(factory);
213 THROW0(not_found_error, 0, "Factory 'sysv' does not exist: no System V thread support under Windows");
216 THROW1(not_found_error, 0, "Factory '%s' does not exist", name);
219 /** Garbage collection
221 * Should be called some time to time to free the memory allocated for processes
222 * that have finished (or killed).
224 void SIMIX_context_empty_trash(void)
226 smx_process_t process = NULL;
229 while ((process = xbt_swag_extract(simix_global->process_to_destroy))){
231 process->name = NULL;
234 for (i = 0; i < process->argc; i++)
235 if (process->argv[i])
236 free(process->argv[i]);