/* mallocator - recycle objects to avoid malloc() / free() */
-/* Copyright (c) 2006 Christophe Thiery. All rights reserved. */
+/* 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->lock = 0;
+}
+
+static XBT_INLINE void lock_destroy(xbt_mallocator_t m)
+{
+}
+
+static XBT_INLINE void lock_acquire(xbt_mallocator_t m)
+{
+ if (initialization_done > 1) {
+ int *lock = &m->lock;
+ while (__sync_lock_test_and_set(lock, 1))
+ /* nop */;
+ }
+}
+
+static XBT_INLINE void lock_release(xbt_mallocator_t m)
+{
+ if (initialization_done > 1)
+ __sync_lock_release(&m->lock);
+}
+
+/**
+ * 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
* 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
+ * when you extract an object from the mallocator (can be NULL)
*
* Create and initialize a new mallocator for a given datatype.
*
* \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) {
-
-
+ pvoid_f_void_t new_f,
+ void_f_pvoid_t free_f,
+ void_f_pvoid_t reset_f)
+{
xbt_mallocator_t m;
- xbt_assert0(size > 0, "size must be positive");
- xbt_assert0(new_f != NULL && free_f != NULL && reset_f != NULL,"invalid parameter");
+ 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);
-
- m->objects = xbt_new0(void*, size);
- m->max_size = size;
+ 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;
}
*
* \see xbt_mallocator_new()
*/
-void xbt_mallocator_free(xbt_mallocator_t m) {
+void xbt_mallocator_free(xbt_mallocator_t m)
+{
int i;
- xbt_assert0(m != NULL, "Invalid parameter");
-
+ 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);
}
* 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() is called on the object.
+ *
+ * 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;
- xbt_assert0(m != NULL, "Invalid parameter");
-
-
- if (m->current_size > 0) {
- /* there is at least an available object */
+void *xbt_mallocator_get(xbt_mallocator_t m)
+{
+ void *object;
+
+ 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();
- }
- m->reset_f(object);
+
+ if (m->reset_f)
+ m->reset_f(object);
return object;
}
*
* \see xbt_mallocator_get()
*/
-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->objects[m->current_size++] = object;
- }
- else {
- /* otherwise we don't have a choice, we must free the object */
- m->free_f(object);
+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);
+ }
}
}
