/* mallocator - recycle objects to avoid malloc() / free() */
-/* Copyright (c) 2006 Christophe Thiery. All rights reserved. */
+/* Copyright (c) 2006-2018. 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 "mallocator_private.h"
+#include "simgrid/modelchecker.h" /* kill mallocators when model-checking is enabled */
+#include "src/internal_config.h"
#include "xbt/asserts.h"
#include "xbt/sysdep.h"
-#include "mallocator_private.h"
+
+#ifndef MIN
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#endif
+#ifndef MAX
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#endif
+
+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 inline void lock_reset(xbt_mallocator_t m)
+{
+ m->lock = 0;
+}
+
+static inline void lock_acquire(xbt_mallocator_t m)
+{
+ if (initialization_done > 1) {
+ while (__atomic_test_and_set(&m->lock, __ATOMIC_ACQUIRE))
+ /* nop */;
+ }
+}
+
+static inline void lock_release(xbt_mallocator_t m)
+{
+ if (initialization_done > 1)
+ __atomic_clear(&m->lock, __ATOMIC_RELEASE);
+}
+
+/**
+ * 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 inline int xbt_mallocator_is_active(void) {
+#if SIMGRID_HAVE_MALLOCATOR
+ 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
+ * \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_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_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;
}
/** \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.
+ * 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) {
-
+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]);
}
*
* 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() is called on the object.
+ * 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;
- 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) */
+ 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 */
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_reset(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;
}
*
* 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().
+ * 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) {
- 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 == NULL) // The mallocators are already destroyed. Bail out ASAP.
+ return;
+ 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 */
+ 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 */
+ 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_reset(m);
+ xbt_mallocator_release(m,object);
+ } else {
+ m->free_f(object);
+ }
}
}
