Check return value for posix_memalign.

[simgrid.git] / src / simix / smx_context.c

diff --git a/src/simix/smx_context.c b/src/simix/smx_context.c
index e638bb7..0bfad29 100644 (file)
--- a/src/simix/smx_context.c
+++ b/src/simix/smx_context.c
@@ -1,6 +1,6 @@
 /* a fast and simple context switching library                              */
 
-/* Copyright (c) 2009-2013. The SimGrid Team.
+/* Copyright (c) 2009-2014. The SimGrid Team.
  * All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
@@ -13,14 +13,22 @@
 #include "smx_private.h"
 #include "simgrid/sg_config.h"
 #include "internal_config.h"
+#include "simgrid/modelchecker.h"
+#include <sys/mman.h>
+
+#ifdef HAVE_VALGRIND_VALGRIND_H
+# include <valgrind/valgrind.h>
+#endif
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix,
                                 "Context switching mechanism");
 
 char* smx_context_factory_name = NULL; /* factory name specified by --cfg=contexts/factory:value */
 smx_ctx_factory_initializer_t smx_factory_initializer_to_use = NULL;
-int smx_context_stack_size = 128 * 1024;
+int smx_context_stack_size;
 int smx_context_stack_size_was_set = 0;
+int smx_context_guard_size;
+int smx_context_guard_size_was_set = 0;
 #ifdef HAVE_THREAD_LOCAL_STORAGE
 static __thread smx_context_t smx_current_context_parallel;
 #else
@@ -99,6 +107,68 @@ void SIMIX_context_mod_exit(void)
   xbt_dict_remove((xbt_dict_t) _sg_cfg_set,"contexts/factory");
 }
 
+void *SIMIX_context_stack_new(void)
+{
+  void *stack;
+
+  if (smx_context_guard_size > 0 && !MC_is_active()) {
+    size_t size = smx_context_stack_size + smx_context_guard_size;
+#ifdef HAVE_MC
+    /* Cannot use posix_memalign when HAVE_MC. Align stack by hand, and save the
+     * pointer returned by xbt_malloc0. */
+    char *alloc = xbt_malloc0(size + xbt_pagesize);
+    stack = alloc - ((uintptr_t)alloc & (xbt_pagesize - 1)) + xbt_pagesize;
+    *((void **)stack - 1) = alloc;
+#else
+    if (posix_memalign(&stack, xbt_pagesize, size) != 0)
+      xbt_die("Failed to allocate stack.");
+#endif
+    if (mprotect(stack, smx_context_guard_size, PROT_NONE) == -1) {
+      XBT_WARN("Failed to protect stack: %s", strerror(errno));
+      /* That's not fatal, pursue anyway. */
+    }
+    stack = (char *)stack + smx_context_guard_size;
+  } else {
+    stack = xbt_malloc0(smx_context_stack_size);
+  }
+
+#ifdef HAVE_VALGRIND_VALGRIND_H
+  unsigned int valgrind_stack_id =
+    VALGRIND_STACK_REGISTER(stack, (char *)stack + smx_context_stack_size);
+  memcpy((char *)stack + smx_context_usable_stack_size, &valgrind_stack_id,
+         sizeof valgrind_stack_id);
+#endif
+
+  return stack;
+}
+
+void SIMIX_context_stack_delete(void *stack)
+{
+  if (!stack)
+    return;
+
+#ifdef HAVE_VALGRIND_VALGRIND_H
+  unsigned int valgrind_stack_id;
+  memcpy(&valgrind_stack_id, (char *)stack + smx_context_usable_stack_size,
+         sizeof valgrind_stack_id);
+  VALGRIND_STACK_DEREGISTER(valgrind_stack_id);
+#endif
+
+  if (smx_context_guard_size > 0 && !MC_is_active()) {
+    stack = (char *)stack - smx_context_guard_size;
+    if (mprotect(stack, smx_context_guard_size,
+                 PROT_READ | PROT_WRITE | PROT_EXEC) == -1) {
+      XBT_WARN("Failed to remove page protection: %s", strerror(errno));
+      /* try to pursue anyway */
+    }
+#ifdef HAVE_MC
+    /* Retrieve the saved pointer.  See SIMIX_context_stack_new above. */
+    stack = *((void **)stack - 1);
+#endif
+  }
+  xbt_free(stack);
+}
+
 /**
  * \brief Returns whether some parallel threads are used
  * for the user contexts.
@@ -127,7 +197,7 @@ XBT_INLINE int SIMIX_context_get_nthreads(void) {
  *
  * \param nb_threads the number of threads to use
  */
-XBT_INLINE void SIMIX_context_set_nthreads(int nb_threads) {
+void SIMIX_context_set_nthreads(int nb_threads) {
   if (nb_threads<=0) {  
      nb_threads = xbt_os_get_numcores();
      XBT_INFO("Auto-setting contexts/nthreads to %d",nb_threads);