feat: add mutex

Makefile

@@ -16,8 +16,8 @@ bins+=31-switch-many
 bins+=32-switch-many-join
 bins+=33-switch-many-cascade
 bins+=51-fibonacci
-#bins+=61-mutex
+bins+=61-mutex
-#bins+=62-mutex
+bins+=62-mutex
 bins+=71-preemption
 bins+=81-deadlock
 

src/thread/thread.c

@@ -21,19 +21,25 @@
 #define GET_LAST_WAITED_THREAD(entry) (entry->last_waited ? entry->last_waited->last_thread : NULL)
 #define IS_WAITED_THREAD_FINISHED(entry) (GET_WAITED_THREAD(entry)->status & FINISHED)
 #define WAITED 0x8
+#define MUTEX_WAITING 0xf0
 #define IS_WAITED(entry) (entry->status & WAITED)
+#define IS_MUTEX_WAITING(entry) (entry->status & MUTEX_WAITING)
 
 #ifndef STACK_SIZE
 #define STACK_SIZE 4096
 #endif
 
+#ifndef HASHMAP_SIZE
+#define HASHMAP_SIZE 16384
+#endif
+
 // Variables used to clean up everything at the end of the processus
 static char stack_for_freeing[STACK_SIZE] = {0};
 static int stack_valgrind_id = 0;
 static ucontext_t context_for_freeing;
 
 struct last_thread_t;
-
+struct mutex_fifo_entry_t;
 
 struct context_entry {
     TAILQ_ENTRY(context_entry)
@@ -43,6 +49,7 @@ struct context_entry {
     void *waiting; // the thread that the entry is waiting for
     void *retvalue; // return value or if the thread is waited, the id of the thread that wait for it
     struct last_thread_t *last_waited;
+    struct mutex_fifo_entry_t* mutex_fifo_entry;
     int valgrind_id;
     char status;
     char stack[STACK_SIZE];
@@ -60,6 +67,14 @@ static struct context_entry* running = NULL;
 
 static TAILQ_HEAD(freed_context_head, context_entry) context_to_freed = TAILQ_HEAD_INITIALIZER(context_to_freed);
 
+
+struct mutex_fifo_entry_t {
+    STAILQ_ENTRY(mutex_fifo_entry_t) link;
+    struct context_entry* thread;
+};
+STAILQ_HEAD(mutex_fifo, mutex_fifo_entry_t) mutex_fifo;
+static struct mutex_fifo* mutex_fifo_hashmap[HASHMAP_SIZE] = {};
+
 int thread_yield(void)
 {
     //TRACE("thread_yield");
@@ -79,7 +94,7 @@ int thread_yield(void)
         return -1;
     }
     TAILQ_REMOVE(&head, first, link);
-    if (!IS_FINISHED(running) && !(IS_WAITING(running) && !IS_WAITED_THREAD_FINISHED(running))) {
+    if (!IS_FINISHED(running) && !IS_MUTEX_WAITING(running) && !(IS_WAITING(running) && !IS_WAITED_THREAD_FINISHED(running))) {
         TAILQ_INSERT_TAIL(&head, running, link);
     }
     TRACE("PICKING %p (previous was %p)", first->id, running->id);
@@ -144,6 +159,7 @@ int thread_create(thread_t* newthread, void* (*func)(void*), void* funcarg)
     new_entry->status = ALLOCATED;
     new_entry->retvalue = NULL;
     new_entry->last_waited = NULL;
+    new_entry->mutex_fifo_entry = NULL;
 
     *newthread = new_entry->id;
 
@@ -272,6 +288,7 @@ void clear_context(void)
     while (!TAILQ_EMPTY(&head)) {
         last = TAILQ_FIRST(&head);
         TAILQ_REMOVE(&head, last, link);
+        free(last->mutex_fifo_entry);
         if (WAS_ALLOCATED(last)) {
             VALGRIND_STACK_DEREGISTER(last->valgrind_id);
         }
@@ -283,12 +300,18 @@ void clear_context(void)
     }
     while (!TAILQ_EMPTY(&context_to_freed)) {
         last = TAILQ_FIRST(&context_to_freed);
+        free(last->mutex_fifo_entry);
         TAILQ_REMOVE(&context_to_freed, last, link);
         if (WAS_ALLOCATED(last)) {
             VALGRIND_STACK_DEREGISTER(last->valgrind_id);
         }
         free(last);
     }
+
+    // Free all the fifo that might have been allocated
+    for (int i = 0 ; i < HASHMAP_SIZE ; ++i)
+        free(mutex_fifo_hashmap[i]);
+
     VALGRIND_STACK_DEREGISTER(stack_valgrind_id);
     exit(0);
 }
@@ -329,24 +352,68 @@ void __attribute__((destructor)) clear_last_thread()
     exit(0);
 }
 
+
 int thread_mutex_init(thread_mutex_t* mutex)
 {
-    return pthread_mutex_init((pthread_mutex_t*)mutex, NULL);
+    long id = ((long)mutex) % HASHMAP_SIZE;
+    if (mutex_fifo_hashmap[id] == NULL)
+    {
+        mutex_fifo_hashmap[id] = malloc(sizeof(mutex_fifo));
+        STAILQ_INIT(mutex_fifo_hashmap[id]);
+    }
+
+    return mutex->dummy = 0;
 }
 
 int thread_mutex_destroy(thread_mutex_t* mutex)
 {
-    return pthread_mutex_destroy((pthread_mutex_t*)mutex);
+    long id = ((long)mutex) % HASHMAP_SIZE;
+    struct mutex_fifo_entry_t* last = NULL;
+
+    while (!STAILQ_EMPTY(mutex_fifo_hashmap[id])) {
+        last = STAILQ_FIRST(mutex_fifo_hashmap[id]);
+        STAILQ_REMOVE_HEAD(mutex_fifo_hashmap[id], link);
+        free(last);
+    }
+
+    return 0;
 }
 
 int thread_mutex_lock(thread_mutex_t* mutex)
 {
-    return pthread_mutex_lock((pthread_mutex_t*)mutex);
+    // Add to mutex fifo
+    long id = ((long)mutex) % HASHMAP_SIZE;
+    DBG("Lock mutex %d\n", id);
+    while (! __sync_bool_compare_and_swap(&mutex->dummy, 0, 1))
+    {
+        DBG("Wait for mutex %d\n", id);
+        if (running->mutex_fifo_entry == NULL)
+            running->mutex_fifo_entry = malloc(sizeof(struct mutex_fifo_entry_t));
+
+        STAILQ_INSERT_TAIL(mutex_fifo_hashmap[id], running->mutex_fifo_entry, link);
+        // Use status to be in waiting state
+        running->status |= MUTEX_WAITING;
+        running->mutex_fifo_entry->thread = running;
+        thread_yield();
+    }
+
+    mutex->dummy = 1;
+    return 0;
 }
 
 int thread_mutex_unlock(thread_mutex_t* mutex)
 {
-    return pthread_mutex_unlock((pthread_mutex_t*)mutex);
+    long id = ((long)mutex) % HASHMAP_SIZE;
+    DBG("Unlock mutex %d\n", id);
+    if (!STAILQ_EMPTY(mutex_fifo_hashmap[id]))
+    {
+        struct mutex_fifo_entry_t* first = STAILQ_FIRST(mutex_fifo_hashmap[id]);
+        STAILQ_REMOVE_HEAD(mutex_fifo_hashmap[id], link);
+
+        first->thread->status &= ~MUTEX_WAITING;
+        TAILQ_INSERT_TAIL(&head, first->thread, link);
     }
 
+    return mutex->dummy = 0;
+}
 #endif