X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/e048b9d6c83f24e8649df8ae09759d4616ec0d30..71a018851ec389e3c5c68e6dda895d47f5a29c5f:/src/xbt/mallocator.c

diff --git a/src/xbt/mallocator.c b/src/xbt/mallocator.c
index 52d77026d3..469c43596a 100644
--- a/src/xbt/mallocator.c
+++ b/src/xbt/mallocator.c
@@ -1,67 +1,250 @@
+/* mallocator - recycle objects to avoid malloc() / free()                  */
+
+/* Copyright (c) 2006-2011. The SimGrid Team.
+ * All rights reserved.                                                     */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
 #include "xbt/mallocator.h"
 #include "xbt/asserts.h"
 #include "xbt/sysdep.h"
+#include "mc/mc.h" /* kill mallocators when model-checking is enabled */
 #include "mallocator_private.h"
 
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_mallocator, xbt, "Mallocators");
+
+/** Implementation note on the mallocators:
+ *
+ * Mallocators and memory mess introduced by model-checking do not mix well
+ * together: the mallocator will give standard memory when we are using raw
+ * memory (so these blocks are killed on restore) and the contrary (so these
+ * blocks will leak across restores).
+ *
+ * In addition, model-checking is activated when the command-line arguments
+ * are parsed, at the beginning of main, while most of the mallocators are
+ * created during the constructor functions launched from xbt_preinit, before
+ * the beginning of the main function.
+ *
+ * We want the code as fast as possible when they are active while we can deal
+ * with a little slow-down when they are inactive. So we start the mallocators
+ * as inactive. When they are so, they check at each use whether they should
+ * switch to the fast active mode or should stay in inactive mode.
+ * Finally, we give external elements a way to switch them
+ * all to the active mode (through xbt_mallocator_initialization_is_done).
+ *
+ * This design avoids to store all mallocators somewhere for later conversion,
+ * which would be hard to achieve provided that all our data structures use
+ * some mallocators internally...
+ */
+
+/* Value != 0 when the framework configuration is done.  Value > 1 if the
+ * mallocators should be protected from concurrent accesses.  */
+static int initialization_done = 0;
+
+static XBT_INLINE void lock_create(xbt_mallocator_t m)
+{
+  m->mutex = initialization_done > 1 ? xbt_os_mutex_init() : NULL;
+}
+
+static XBT_INLINE void lock_destroy(xbt_mallocator_t m)
+{
+  if (m->mutex)
+    xbt_os_mutex_destroy(m->mutex);
+}
+
+static XBT_INLINE void lock_acquire(xbt_mallocator_t m)
+{
+  if (m->mutex)
+    xbt_os_mutex_acquire(m->mutex);
+}
+
+static XBT_INLINE void lock_release(xbt_mallocator_t m)
+{
+  if (m->mutex)
+    xbt_os_mutex_release(m->mutex);
+}
+
+/**
+ * This function must be called once the framework configuration is done. If not,
+ * mallocators will never get used. Check the implementation notes in
+ * src/xbt/mallocator.c for the justification of this.
+ *
+ * For example, surf_config uses this function to tell to the mallocators that
+ * the simgrid
+ * configuration is now finished and that it can create them if not done yet */
+void xbt_mallocator_initialization_is_done(int protect)
+{
+  initialization_done = protect ? 2 : 1;
+}
+
+/** used by the module to know if it's time to activate the mallocators yet */
+static XBT_INLINE int xbt_mallocator_is_active(void) {
+#if MALLOCATOR_COMPILED_IN
+  return initialization_done && !MC_is_active();
+#else
+  return 0;
+#endif
+}
+
+/**
+ * \brief Constructor
+ * \param size size of the internal stack: number of objects the mallocator
+ * will be able to store
+ * \param new_f function to allocate a new object of your datatype, called
+ * in \a xbt_mallocator_get() when the mallocator is empty
+ * \param free_f function to free an object of your datatype, called
+ * in \a xbt_mallocator_release() when the stack is full, and when
+ * the mallocator is freed.
+ * \param reset_f function to reinitialise an object of your datatype, called
+ * when you extract an object from the mallocator (can be NULL)
+ *
+ * Create and initialize a new mallocator for a given datatype.
+ *
+ * \return pointer to the created mallocator
+ * \see xbt_mallocator_free()
+ */
 xbt_mallocator_t xbt_mallocator_new(int size,
-				    pvoid_f_void_t new_f,
-				    void_f_pvoid_t free_f,
-				    void_f_pvoid_t reset_f) {
-  xbt_assert0(size > 0, "size must be positive");
-  xbt_assert0(new_f != NULL && free_f != NULL && reset_f != NULL,
-	      "invalid parameter");
-  xbt_mallocator_t m = xbt_new0(s_xbt_mallocator_t, 1);
-
-  m->objects = xbt_new0(void*, size);
-  m->max_size = size;
+                                    pvoid_f_void_t new_f,
+                                    void_f_pvoid_t free_f,
+                                    void_f_pvoid_t reset_f)
+{
+  xbt_mallocator_t m;
+
+  xbt_assert(size > 0, "size must be positive");
+  xbt_assert(new_f != NULL && free_f != NULL, "invalid parameter");
+
+  m = xbt_new0(s_xbt_mallocator_t, 1);
+  XBT_VERB("Create mallocator %p (%s)",
+           m, xbt_mallocator_is_active() ? "enabled" : "disabled");
   m->current_size = 0;
   m->new_f = new_f;
   m->free_f = free_f;
   m->reset_f = reset_f;
+  m->max_size = size;
 
   return m;
 }
 
-/* Destroy the mallocator and all its data */
-void xbt_mallocator_free(xbt_mallocator_t m) {
-  xbt_assert0(m != NULL, "Invalid parameter");
+/** \brief Destructor
+ * \param m the mallocator you want to destroy
+ *
+ * Destroy the mallocator and all its data. The function
+ * free_f is called on each object in the mallocator.
+ *
+ * \see xbt_mallocator_new()
+ */
+void xbt_mallocator_free(xbt_mallocator_t m)
+{
 
   int i;
+  xbt_assert(m != NULL, "Invalid parameter");
+
+  XBT_VERB("Frees mallocator %p (size:%d/%d)", m, m->current_size,
+        m->max_size);
   for (i = 0; i < m->current_size; i++) {
     m->free_f(m->objects[i]);
   }
   xbt_free(m->objects);
+  lock_destroy(m);
   xbt_free(m);
 }
 
-/* Return an object (use this function instead of malloc) */
-void *xbt_mallocator_get(xbt_mallocator_t m) {
-  xbt_assert0(m != NULL, "Invalid parameter");
-
+/**
+ * \brief Extract an object from a mallocator
+ * \param m a mallocator
+ *
+ * Remove an object from the mallocator and return it.
+ * This function is designed to be used instead of malloc().
+ * If the mallocator is not empty, an object is
+ * extracted from the mallocator and no malloc is done.
+ *
+ * If the mallocator is empty, a new object is created,
+ * by calling the function new_f().
+ *
+ * In both cases, the function reset_f() (if defined) is called on the object.
+ *
+ * \see xbt_mallocator_release()
+ */
+void *xbt_mallocator_get(xbt_mallocator_t m)
+{
   void *object;
-  if (m->current_size > 0) {
-    /* there is at least an available object */
-    return m->objects[--m->current_size];
+
+  if (m->objects != NULL) { // this mallocator is active, stop thinking and go for it!
+    lock_acquire(m);
+    if (m->current_size <= 0) {
+      /* No object is ready yet. Create a bunch of them to try to group the
+       * mallocs on the same memory pages (to help the cache lines) */
+
+      /* XBT_DEBUG("Create a new object for mallocator %p (size:%d/%d)", */
+      /*           m, m->current_size, m->max_size); */
+      int i;
+      int amount = MIN(m->max_size / 2, 1000);
+      for (i = 0; i < amount; i++)
+        m->objects[i] = m->new_f();
+      m->current_size = amount;
+    }
+
+    /* there is at least an available object, now */
+    /* XBT_DEBUG("Reuse an old object for mallocator %p (size:%d/%d)", */
+    /*           m, m->current_size, m->max_size); */
+    object = m->objects[--m->current_size];
+    lock_release(m);
+  } else {
+    if (xbt_mallocator_is_active()) {
+      // We have to switch this mallocator from inactive to active (and then get an object)
+      m->objects = xbt_new0(void *, m->max_size);
+      lock_create(m);
+      return xbt_mallocator_get(m);
+    } else {
+      object = m->new_f();
+    }
   }
-  else {
-    /* otherwise we must allocate a new object */
-    object = m->new_f();
+
+  if (m->reset_f)
     m->reset_f(object);
-    return object;
-  }
+  return object;
 }
 
-/* Release an object (use this function instead of free) */
-void xbt_mallocator_release(xbt_mallocator_t m, void *object) {
-  xbt_assert0(m != NULL && object != NULL, "Invalid parameter");
-
-  if (m->current_size < m->max_size) {
-    /* there is enough place to push the object */
-    m->reset_f(object);
-    m->objects[m->current_size++] = object;
-  }
-  else {
-    /* otherwise we don't have a choice, we must free the object */
-    m->free_f(object);
+/** \brief Push an object into a mallocator
+ * \param m a mallocator
+ * \param object an object you don't need anymore
+ *
+ * Push into the mallocator an object you don't need anymore.
+ * This function is designed to be used instead of free().
+ * If the mallocator is not full, your object if stored into
+ * the mallocator and no free is done.
+ * If the mallocator is full, the object is freed by calling
+ * the function free_f().
+ *
+ * \see xbt_mallocator_get()
+ */
+void xbt_mallocator_release(xbt_mallocator_t m, void *object)
+{
+  if (m->objects != NULL) { // Go for it
+    lock_acquire(m);
+    if (m->current_size < m->max_size) {
+      /* there is enough place to push the object */
+      /* XBT_DEBUG
+         ("Store deleted object in mallocator %p for further use (size:%d/%d)",
+         m, m->current_size, m->max_size); */
+      m->objects[m->current_size++] = object;
+      lock_release(m);
+    } else {
+      lock_release(m);
+      /* otherwise we don't have a choice, we must free the object */
+      /* XBT_DEBUG("Free deleted object: mallocator %p is full (size:%d/%d)", m,
+         m->current_size, m->max_size); */
+      m->free_f(object);
+    }
+  } else {
+    if (xbt_mallocator_is_active()) {
+      // We have to switch this mallocator from inactive to active (and then store that object)
+      m->objects = xbt_new0(void *, m->max_size);
+      lock_create(m);
+      xbt_mallocator_release(m,object);
+    } else {
+      m->free_f(object);
+    }
   }
 }