src/simix/xbt_context_sysv.c

   1 /* $Id$ */
   2
   3 /* context_sysv - implementation of context switching with ucontextes from Sys V */
   4
   5 /* Copyright (c) 2004-2008 the SimGrid team. All right reserved */
   6
   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. */
   9
  10 #include "xbt/ex_interface.h"
  11 #include "xbt_context_private.h"
  12
  13 #include "context_sysv_config.h"        /* loads context system definitions                             */
  14 #include "portable.h"
  15 #include <ucontext.h>           /* context relative declarations                                */
  16 #define STACK_SIZE 128*1024     /* lower this if you want to reduce the memory consumption      */
  17 #ifdef HAVE_VALGRIND_VALGRIND_H
  18 #  include <valgrind/valgrind.h>
  19 #endif /* HAVE_VALGRIND_VALGRIND_H */
  20
  21 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_context);
  22
  23 typedef struct s_xbt_ctx_sysv {
  24   XBT_CTX_BASE_T;
  25   ucontext_t uc;                /* the thread that execute the code */
  26   char stack[STACK_SIZE];       /* the thread stack size */
  27   smx_process_t prev;           /* the previous process */
  28 #ifdef HAVE_VALGRIND_VALGRIND_H
  29   unsigned int valgrind_stack_id;       /* the valgrind stack id */
  30 #endif
  31 } s_xbt_ctx_sysv_t, *xbt_ctx_sysv_t;
  32
  33
  34 /* callback: context fetching */
  35 static ex_ctx_t *xbt_jcontext_ex_ctx(void);
  36
  37 /* callback: termination */
  38 static void xbt_jcontext_ex_terminate(xbt_ex_t * e);
  39
  40 static int
  41 smx_ctx_sysv_factory_create_context(smx_process_t *smx_process, xbt_main_func_t code);
  42
  43 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t * factory);
  44
  45 static int smx_ctx_sysv_factory_create_maestro_context(smx_process_t * maestro);
  46
  47 static void smx_ctx_sysv_free(smx_process_t process);
  48
  49 static void smx_ctx_sysv_kill(smx_process_t process);
  50
  51 static void smx_ctx_sysv_schedule(smx_process_t process);
  52
  53 static void smx_ctx_sysv_yield(void);
  54
  55 static void smx_ctx_sysv_start(smx_process_t process);
  56
  57 static void smx_ctx_sysv_stop(int exit_code);
  58
  59 static void smx_ctx_sysv_swap(smx_process_t process);
  60
  61 static void smx_ctx_sysv_schedule(smx_process_t process);
  62
  63 static void smx_ctx_sysv_yield(void);
  64
  65 static void smx_ctx_sysv_suspend(smx_process_t process);
  66
  67 static void smx_ctx_sysv_resume(smx_process_t process);
  68
  69 static void smx_ctx_sysv_wrapper(void);
  70
  71 /* callback: context fetching */
  72 static ex_ctx_t *xbt_ctx_sysv_ex_ctx(void)
  73 {
  74   return simix_global->current_process->context->exception;
  75 }
  76
  77 /* callback: termination */
  78 static void xbt_ctx_sysv_ex_terminate(xbt_ex_t * e)
  79 {
  80   xbt_ex_display(e);
  81   abort();
  82 }
  83
  84 void SIMIX_ctx_sysv_factory_init(smx_context_factory_t * factory)
  85 {
  86   *factory = xbt_new0(s_smx_context_factory_t, 1);
  87
  88   (*factory)->create_context = smx_ctx_sysv_factory_create_context;
  89   (*factory)->finalize = smx_ctx_sysv_factory_finalize;
  90   (*factory)->create_maestro_context = smx_ctx_sysv_factory_create_maestro_context;
  91   (*factory)->free = smx_ctx_sysv_free;
  92   (*factory)->kill = smx_ctx_sysv_kill;
  93   (*factory)->schedule = smx_ctx_sysv_schedule;
  94   (*factory)->yield = smx_ctx_sysv_yield;
  95   (*factory)->start = smx_ctx_sysv_start;
  96   (*factory)->stop = smx_ctx_sysv_stop;
  97   (*factory)->name = "smx_sysv_context_factory";
  98
  99   /* context exception handlers */
 100   __xbt_ex_ctx = xbt_ctx_sysv_ex_ctx;
 101   __xbt_ex_terminate = xbt_ctx_sysv_ex_terminate;
 102 }
 103
 104 static int smx_ctx_sysv_factory_create_maestro_context(smx_process_t *maestro)
 105 {
 106   xbt_ctx_sysv_t context = xbt_new0(s_xbt_ctx_sysv_t, 1);
 107
 108   context->exception = xbt_new(ex_ctx_t, 1);
 109   XBT_CTX_INITIALIZE(context->exception);
 110
 111   (*maestro)->context = (xbt_context_t) context;
 112
 113   return 0;
 114
 115 }
 116
 117
 118 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t * factory)
 119 {
 120   /*FIXME free(maestro_context->exception);*/
 121   free(*factory);
 122   *factory = NULL;
 123   return 0;
 124 }
 125
 126 static int
 127 smx_ctx_sysv_factory_create_context(smx_process_t *smx_process, xbt_main_func_t code)
 128 {
 129   VERB1("Create context %s", (*smx_process)->name);
 130   xbt_ctx_sysv_t context = xbt_new0(s_xbt_ctx_sysv_t, 1);
 131
 132   context->code = code;
 133
 134   xbt_assert2(getcontext(&(context->uc)) == 0,
 135               "Error in context saving: %d (%s)", errno, strerror(errno));
 136   context->uc.uc_link = NULL;
 137   context->uc.uc_stack.ss_sp =
 138     pth_skaddr_makecontext(context->stack, STACK_SIZE);
 139   context->uc.uc_stack.ss_size =
 140     pth_sksize_makecontext(context->stack, STACK_SIZE);
 141 #ifdef HAVE_VALGRIND_VALGRIND_H
 142   context->valgrind_stack_id =
 143     VALGRIND_STACK_REGISTER(context->uc.uc_stack.ss_sp,
 144                             ((char *) context->uc.uc_stack.ss_sp) +
 145                             context->uc.uc_stack.ss_size);
 146 #endif /* HAVE_VALGRIND_VALGRIND_H */
 147
 148   context->exception = xbt_new(ex_ctx_t, 1);
 149   XBT_CTX_INITIALIZE(context->exception);
 150   (*smx_process)->context = (xbt_context_t)context;
 151   (*smx_process)->iwannadie = 0;
 152
 153   /* FIXME: Check what should return */
 154   return 1;
 155 }
 156
 157 static void smx_ctx_sysv_free(smx_process_t process)
 158 {
 159   xbt_ctx_sysv_t context = (xbt_ctx_sysv_t)process->context;
 160   if (context){
 161
 162     if (context->exception)
 163       free(context->exception);
 164
 165 #ifdef HAVE_VALGRIND_VALGRIND_H
 166     VALGRIND_STACK_DEREGISTER(((xbt_ctx_sysv_t) context)->valgrind_stack_id);
 167 #endif /* HAVE_VALGRIND_VALGRIND_H */
 168
 169     /* destroy the context */
 170     free(context);
 171   }
 172 }
 173
 174 static void smx_ctx_sysv_kill(smx_process_t process)
 175 {
 176   DEBUG2("Kill process '%s' (from '%s')", process->name,
 177          simix_global->current_process->name);
 178   process->iwannadie = 1;
 179   smx_ctx_sysv_swap(process);
 180 }
 181
 182 /**
 183  * \param context the winner
 184  *
 185  * Calling this function blocks the current context and schedule \a context.
 186  * When \a context will call xbt_context_yield, it will return
 187  * to this function as if nothing had happened.
 188  *
 189  * Only the maestro can call this function to run a given process.
 190  */
 191 static void smx_ctx_sysv_schedule(smx_process_t process)
 192 {
 193   DEBUG1("Schedule process '%s'", process->name);
 194   xbt_assert0((simix_global->current_process == simix_global->maestro_process),
 195               "You are not supposed to run this function here!");
 196   smx_ctx_sysv_swap(process);
 197 }
 198
 199 /**
 200  * Calling this function makes the current context yield. The context
 201  * that scheduled it returns from xbt_context_schedule as if nothing
 202  * had happened.
 203  *
 204  * Only the processes can call this function, giving back the control
 205  * to the maestro
 206  */
 207 static void smx_ctx_sysv_yield(void)
 208 {
 209   DEBUG1("Yielding context '%s'", simix_global->current_process->name);
 210   xbt_assert0((simix_global->current_process != simix_global->maestro_process),
 211               "You are not supposed to run this function here!");
 212   smx_ctx_sysv_swap(simix_global->current_process);
 213 }
 214
 215 static void smx_ctx_sysv_start(smx_process_t process)
 216 {
 217   /*DEBUG1("Start context '%s'", context->name);*/
 218   makecontext(&(((xbt_ctx_sysv_t) process->context)->uc), smx_ctx_sysv_wrapper, 0);
 219 }
 220
 221 static void smx_ctx_sysv_stop(int exit_code)
 222 {
 223   /* please no debug here: our procdata was already free'd */
 224   if (simix_global->current_process->cleanup_func)
 225     ((*simix_global->current_process->cleanup_func)) (simix_global->current_process->cleanup_arg);
 226
 227   smx_ctx_sysv_swap(simix_global->current_process);
 228 }
 229
 230 static void smx_ctx_sysv_swap(smx_process_t process)
 231 {
 232   DEBUG2("Swap context: '%s' -> '%s'", simix_global->current_process->name, process->name);
 233   xbt_assert0(simix_global->current_process, "You have to call context_init() first.");
 234   xbt_assert0(process, "Invalid argument");
 235
 236   if (((xbt_ctx_sysv_t) process->context)->prev == NULL)
 237     smx_ctx_sysv_resume(process);
 238   else
 239     smx_ctx_sysv_suspend(process);
 240
 241   if (simix_global->current_process->iwannadie)
 242     smx_ctx_sysv_stop(1);
 243 }
 244
 245 static void smx_ctx_sysv_wrapper(void)
 246 {
 247   smx_ctx_sysv_stop((*(simix_global->current_process->context->code))
 248                     (simix_global->current_process->argc, simix_global->current_process->argv));
 249 }
 250
 251 static void smx_ctx_sysv_suspend(smx_process_t process)
 252 {
 253   int rv;
 254
 255   DEBUG1("Suspend context: '%s'", simix_global->current_process->name);
 256   smx_process_t prev_process = ((xbt_ctx_sysv_t) process->context)->prev;
 257
 258   simix_global->current_process = (smx_process_t) (((xbt_ctx_sysv_t) process->context)->prev);
 259
 260   ((xbt_ctx_sysv_t) process->context)->prev = NULL;
 261
 262   rv = swapcontext(&(((xbt_ctx_sysv_t) process->context)->uc), &(((xbt_ctx_sysv_t)prev_process->context)->uc));
 263
 264   xbt_assert0((rv == 0), "Context swapping failure");
 265 }
 266
 267 static void smx_ctx_sysv_resume(smx_process_t process)
 268 {
 269   int rv;
 270   xbt_ctx_sysv_t new_context = (xbt_ctx_sysv_t)process->context;
 271   xbt_ctx_sysv_t prev_context = (xbt_ctx_sysv_t)simix_global->current_process->context;
 272
 273   DEBUG2("Resume context: '%s' (from '%s')", process->name,
 274          simix_global->current_process->name);
 275
 276   ((xbt_ctx_sysv_t) process->context)->prev = simix_global->current_process;
 277
 278   simix_global->current_process = process;
 279
 280   rv = swapcontext(&prev_context->uc, &new_context->uc);
 281
 282   xbt_assert0((rv == 0), "Context swapping failure");
 283 }