X-Git-Url: http://demsky.eecs.uci.edu/git/?p=model-checker-benchmarks.git;a=blobdiff_plain;f=treiber-stack%2Fmy_stack.c;fp=treiber-stack%2Fmy_stack.c;h=5f3cc89300d9b621e91c59227633af8929a64cf3;hp=0000000000000000000000000000000000000000;hb=e326d381460902d927b8862149ce5382f8509bbd;hpb=f19c4f0d0d8c054fdea82137c57dc0dca3059704

diff --git a/treiber-stack/my_stack.c b/treiber-stack/my_stack.c
new file mode 100644
index 0000000..5f3cc89
--- /dev/null
+++ b/treiber-stack/my_stack.c
@@ -0,0 +1,123 @@
+#include <threads.h>
+#include <stdlib.h>
+#include "librace.h"
+#include "model-assert.h"
+
+#include "my_stack.h"
+
+#define MAX_FREELIST 4 /* Each thread can own up to MAX_FREELIST free nodes */
+#define INITIAL_FREE 2 /* Each thread starts with INITIAL_FREE free nodes */
+
+#define POISON_IDX 0x666
+
+static unsigned int (*free_lists)[MAX_FREELIST];
+
+/* Search this thread's free list for a "new" node */
+static unsigned int new_node()
+{
+	int i;
+	int t = get_thread_num();
+	for (i = 0; i < MAX_FREELIST; i++) {
+		//unsigned int node = load_32(&free_lists[t][i]);
+		unsigned int node = free_lists[t][i];
+		if (node) {
+			//store_32(&free_lists[t][i], 0);
+			free_lists[t][i] = 0;
+			return node;
+		}
+	}
+	/* free_list is empty? */
+	MODEL_ASSERT(0);
+	return 0;
+}
+
+/* Place this node index back on this thread's free list */
+static void reclaim(unsigned int node)
+{
+	int i;
+	int t = get_thread_num();
+
+	/* Don't reclaim NULL node */
+	//MODEL_ASSERT(node);
+
+	for (i = 0; i < MAX_FREELIST; i++) {
+		/* Should never race with our own thread here */
+		//unsigned int idx = load_32(&free_lists[t][i]);
+		unsigned int idx = free_lists[t][i];
+
+		/* Found empty spot in free list */
+		if (idx == 0) {
+			//store_32(&free_lists[t][i], node);
+			free_lists[t][i] = node;
+			return;
+		}
+	}
+	/* free list is full? */
+	MODEL_ASSERT(0);
+}
+
+void init_stack(stack_t *s, int num_threads)
+{
+	int i, j;
+
+	/* Initialize each thread's free list with INITIAL_FREE pointers */
+	/* The actual nodes are initialized with poison indexes */
+	free_lists = malloc(num_threads * sizeof(*free_lists));
+	for (i = 0; i < num_threads; i++) {
+		for (j = 0; j < INITIAL_FREE; j++) {
+			free_lists[i][j] = 1 + i * MAX_FREELIST + j;
+			atomic_init(&s->nodes[free_lists[i][j]].next, MAKE_POINTER(POISON_IDX, 0));
+		}
+	}
+
+	/* initialize stack */
+	atomic_init(&s->top, MAKE_POINTER(0, 0));
+}
+
+void push(stack_t *s, unsigned int val) {
+	unsigned int nodeIdx = new_node();
+	node_t *node = &s->nodes[nodeIdx];
+	node->value = val;
+	pointer oldTop, newTop;
+	bool success;
+	while (true) {
+		// acquire
+		oldTop = atomic_load_explicit(&s->top, acquire);
+		newTop = MAKE_POINTER(nodeIdx, get_count(oldTop) + 1);
+		// relaxed
+		atomic_store_explicit(&node->next, oldTop, relaxed);
+
+		// release & relaxed
+		success = atomic_compare_exchange_strong_explicit(&s->top, &oldTop,
+			newTop, release, relaxed);
+		if (success)
+			break;
+	} 
+}
+
+unsigned int pop(stack_t *s) 
+{
+	pointer oldTop, newTop, next;
+	node_t *node;
+	bool success;
+	int val;
+	while (true) {
+		// acquire
+		oldTop = atomic_load_explicit(&s->top, acquire);
+		if (get_ptr(oldTop) == 0)
+			return 0;
+		node = &s->nodes[get_ptr(oldTop)];
+		// relaxed
+		next = atomic_load_explicit(&node->next, relaxed);
+		newTop = MAKE_POINTER(get_ptr(next), get_count(oldTop) + 1);
+		// release & relaxed
+		success = atomic_compare_exchange_strong_explicit(&s->top, &oldTop,
+			newTop, release, relaxed);
+		if (success)
+			break;
+	}
+	val = node->value;
+	/* Reclaim the used slot */
+	reclaim(get_ptr(oldTop));
+	return val;
+}