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 {
26 ucontext_t uc; /* the thread that execute the code */
27 char stack[STACK_SIZE]; /* the thread stack size */
28 struct s_smx_ctx_sysv *prev; /* the previous process */
29 #ifdef HAVE_VALGRIND_VALGRIND_H
30 unsigned int valgrind_stack_id; /* the valgrind stack id */
32 } s_smx_ctx_sysv_t, *smx_ctx_sysv_t;
35 smx_ctx_sysv_factory_create_context(xbt_main_func_t code, int argc, char** argv,
36 void_f_pvoid_t cleanup_func, void* cleanup_arg);
38 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory);
40 static void smx_ctx_sysv_free(smx_context_t context);
42 static void smx_ctx_sysv_stop(smx_context_t context);
44 static void smx_ctx_sysv_suspend(smx_context_t context);
47 smx_ctx_sysv_resume(smx_context_t old_context, smx_context_t new_context);
49 static void smx_ctx_sysv_wrapper(void);
51 void SIMIX_ctx_sysv_factory_init(smx_context_factory_t *factory)
53 *factory = xbt_new0(s_smx_context_factory_t, 1);
55 (*factory)->create_context = smx_ctx_sysv_factory_create_context;
56 (*factory)->finalize = smx_ctx_sysv_factory_finalize;
57 (*factory)->free = smx_ctx_sysv_free;
58 (*factory)->stop = smx_ctx_sysv_stop;
59 (*factory)->suspend = smx_ctx_sysv_suspend;
60 (*factory)->resume = smx_ctx_sysv_resume;
61 (*factory)->name = "smx_sysv_context_factory";
64 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t * factory)
72 smx_ctx_sysv_factory_create_context(xbt_main_func_t code, int argc, char** argv,
73 void_f_pvoid_t cleanup_func, void* cleanup_arg)
75 smx_ctx_sysv_t context = xbt_new0(s_smx_ctx_sysv_t, 1);
77 /* If the user provided a function for the process then use it
78 otherwise is the context for maestro */
82 xbt_assert2(getcontext(&(context->uc)) == 0,
83 "Error in context saving: %d (%s)", errno, strerror(errno));
85 context->uc.uc_link = NULL;
87 context->uc.uc_stack.ss_sp =
88 pth_skaddr_makecontext(context->stack, STACK_SIZE);
90 context->uc.uc_stack.ss_size =
91 pth_sksize_makecontext(context->stack, STACK_SIZE);
93 #ifdef HAVE_VALGRIND_VALGRIND_H
94 context->valgrind_stack_id =
95 VALGRIND_STACK_REGISTER(context->uc.uc_stack.ss_sp,
96 ((char *) context->uc.uc_stack.ss_sp) +
97 context->uc.uc_stack.ss_size);
98 #endif /* HAVE_VALGRIND_VALGRIND_H */
100 context->argc = argc;
101 context->argv = argv;
102 context->cleanup_func = cleanup_func;
103 context->cleanup_arg = cleanup_arg;
105 makecontext(&((smx_ctx_sysv_t)context)->uc, smx_ctx_sysv_wrapper, 0);
108 return (smx_context_t)context;
111 static void smx_ctx_sysv_free(smx_context_t pcontext)
114 smx_ctx_sysv_t context = (smx_ctx_sysv_t)pcontext;
117 #ifdef HAVE_VALGRIND_VALGRIND_H
118 VALGRIND_STACK_DEREGISTER(((smx_ctx_sysv_t) context)->valgrind_stack_id);
119 #endif /* HAVE_VALGRIND_VALGRIND_H */
123 for (i = 0; i < context->argc; i++)
124 if (context->argv[i])
125 free(context->argv[i]);
130 /* destroy the context */
135 static void smx_ctx_sysv_stop(smx_context_t pcontext)
137 smx_ctx_sysv_t context = (smx_ctx_sysv_t)pcontext;
139 if (context->cleanup_func)
140 (*context->cleanup_func) (context->cleanup_arg);
142 smx_ctx_sysv_suspend(pcontext);
145 static void smx_ctx_sysv_wrapper()
147 /*FIXME: I would like to avoid accessing simix_global to get the current
148 context by passing it as an argument of the wrapper function. The problem
149 is that this function is called from smx_ctx_sysv_start, and uses
150 makecontext for calling it, and the stupid posix specification states that
151 all the arguments of the function should be int(32 bits), making it useless
152 in 64-bit architectures where pointers are 64 bit long.
154 smx_ctx_sysv_t context =
155 (smx_ctx_sysv_t)simix_global->current_process->context;
157 (context->code) (context->argc, context->argv);
159 smx_ctx_sysv_stop((smx_context_t)context);
162 static void smx_ctx_sysv_suspend(smx_context_t context)
166 smx_ctx_sysv_t prev_context = ((smx_ctx_sysv_t) context)->prev;
168 ((smx_ctx_sysv_t) context)->prev = NULL;
170 rv = swapcontext(&((smx_ctx_sysv_t) context)->uc, &prev_context->uc);
172 xbt_assert0((rv == 0), "Context swapping failure");
176 smx_ctx_sysv_resume(smx_context_t old_context, smx_context_t new_context)
180 ((smx_ctx_sysv_t) new_context)->prev = (smx_ctx_sysv_t)old_context;
182 rv = swapcontext(&((smx_ctx_sysv_t)old_context)->uc,
183 &((smx_ctx_sysv_t)new_context)->uc);
185 xbt_assert0((rv == 0), "Context swapping failure");