3 /* context_sysv - implementation of context switching with ucontextes from Sys V */
5 /* Copyright (c) 2004-2008 the SimGrid team. All right reserved */
7 /* This program is free software; you can redistribute it and/or modify it
8 * under the terms of the license (GNU LGPL) which comes with this package. */
11 #include "context_sysv_config.h" /* loads context system definitions */
13 #include <ucontext.h> /* context relative declarations */
15 /* lower this if you want to reduce the memory consumption */
16 #define STACK_SIZE 128*1024
18 #ifdef HAVE_VALGRIND_VALGRIND_H
19 # include <valgrind/valgrind.h>
20 #endif /* HAVE_VALGRIND_VALGRIND_H */
22 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
24 typedef struct s_smx_ctx_sysv {
25 s_smx_ctx_base_t super; /* Fields of super implementation */
26 ucontext_t uc; /* the thread that execute the code */
27 char stack[STACK_SIZE]; /* the thread stack size */
28 #ifdef HAVE_VALGRIND_VALGRIND_H
29 unsigned int valgrind_stack_id; /* the valgrind stack id */
31 } s_smx_ctx_sysv_t, *smx_ctx_sysv_t;
34 smx_ctx_sysv_factory_create_context(xbt_main_func_t code, int argc, char** argv,
35 void_f_pvoid_t cleanup_func, void* cleanup_arg);
37 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory);
39 static void smx_ctx_sysv_free(smx_context_t context);
40 static void smx_ctx_sysv_stop(smx_context_t context);
41 static void smx_ctx_sysv_suspend(smx_context_t context);
42 static void smx_ctx_sysv_resume(smx_context_t new_context);
44 static void smx_ctx_sysv_wrapper(void);
46 void SIMIX_ctx_sysv_factory_init(smx_context_factory_t *factory)
48 *factory = xbt_new0(s_smx_context_factory_t, 1);
50 (*factory)->create_context = smx_ctx_sysv_factory_create_context;
51 (*factory)->finalize = smx_ctx_sysv_factory_finalize;
52 (*factory)->free = smx_ctx_sysv_free;
53 (*factory)->stop = smx_ctx_sysv_stop;
54 (*factory)->suspend = smx_ctx_sysv_suspend;
55 (*factory)->resume = smx_ctx_sysv_resume;
56 (*factory)->name = "smx_sysv_context_factory";
59 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t * factory)
67 smx_ctx_sysv_factory_create_context(xbt_main_func_t code, int argc, char** argv,
68 void_f_pvoid_t cleanup_func, void* cleanup_arg)
70 smx_ctx_sysv_t context = xbt_new0(s_smx_ctx_sysv_t, 1);
72 /* If the user provided a function for the process then use it
73 otherwise is the context for maestro */
75 context->super.code = code;
77 xbt_assert2(getcontext(&(context->uc)) == 0,
78 "Error in context saving: %d (%s)", errno, strerror(errno));
80 context->uc.uc_link = NULL;
82 context->uc.uc_stack.ss_sp =
83 pth_skaddr_makecontext(context->stack, STACK_SIZE);
85 context->uc.uc_stack.ss_size =
86 pth_sksize_makecontext(context->stack, STACK_SIZE);
88 #ifdef HAVE_VALGRIND_VALGRIND_H
89 context->valgrind_stack_id =
90 VALGRIND_STACK_REGISTER(context->uc.uc_stack.ss_sp,
91 ((char *) context->uc.uc_stack.ss_sp) +
92 context->uc.uc_stack.ss_size);
93 #endif /* HAVE_VALGRIND_VALGRIND_H */
95 context->super.argc = argc;
96 context->super.argv = argv;
97 context->super.cleanup_func = cleanup_func;
98 context->super.cleanup_arg = cleanup_arg;
100 makecontext(&((smx_ctx_sysv_t)context)->uc, smx_ctx_sysv_wrapper, 0);
103 return (smx_context_t)context;
106 static void smx_ctx_sysv_free(smx_context_t pcontext)
109 smx_ctx_sysv_t context = (smx_ctx_sysv_t)pcontext;
112 #ifdef HAVE_VALGRIND_VALGRIND_H
113 VALGRIND_STACK_DEREGISTER(((smx_ctx_sysv_t) context)->valgrind_stack_id);
114 #endif /* HAVE_VALGRIND_VALGRIND_H */
117 if (context->super.argv) {
118 for (i = 0; i < context->super.argc; i++)
119 if (context->super.argv[i])
120 free(context->super.argv[i]);
122 free(context->super.argv);
125 /* destroy the context */
130 static void smx_ctx_sysv_stop(smx_context_t pcontext)
132 smx_ctx_sysv_t context = (smx_ctx_sysv_t)pcontext;
134 if (context->super.cleanup_func)
135 (*context->super.cleanup_func) (context->super.cleanup_arg);
137 smx_ctx_sysv_suspend(pcontext);
140 static void smx_ctx_sysv_wrapper()
142 /*FIXME: I would like to avoid accessing simix_global to get the current
143 context by passing it as an argument of the wrapper function. The problem
144 is that this function is called from smx_ctx_sysv_start, and uses
145 makecontext for calling it, and the stupid posix specification states that
146 all the arguments of the function should be int(32 bits), making it useless
147 in 64-bit architectures where pointers are 64 bit long.
149 smx_ctx_sysv_t context =
150 (smx_ctx_sysv_t)simix_global->current_process->context;
152 (context->super.code) (context->super.argc, context->super.argv);
154 smx_ctx_sysv_stop((smx_context_t)context);
157 static void smx_ctx_sysv_suspend(smx_context_t context) {
159 ucontext_t maestro_ctx = ((smx_ctx_sysv_t)simix_global->maestro_process->context)->uc;
161 rv = swapcontext(&((smx_ctx_sysv_t) context)->uc, &maestro_ctx);
163 xbt_assert0((rv == 0), "Context swapping failure");
167 smx_ctx_sysv_resume(smx_context_t new_context) {
169 smx_ctx_sysv_t maestro = (smx_ctx_sysv_t)simix_global->maestro_process->context;
171 rv = swapcontext(&(maestro->uc), &((smx_ctx_sysv_t)new_context)->uc);
173 xbt_assert0((rv == 0), "Context swapping failure");