/*
- * Copyright (c) 2013 Nicira, Inc.
+ * Copyright (c) 2013, 2014 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
typedef void destructor_func(void *);
XPTHREAD_FUNC2(pthread_key_create, pthread_key_t *, destructor_func *);
+XPTHREAD_FUNC1(pthread_key_delete, pthread_key_t);
XPTHREAD_FUNC2(pthread_setspecific, pthread_key_t, const void *);
static void
{
return !must_not_fork;
}
+\f
+/* Parses /proc/cpuinfo for the total number of physical cores on this system
+ * across all CPU packages, not counting hyper-threads.
+ *
+ * Sets *n_cores to the total number of cores on this system, or 0 if the
+ * number cannot be determined. */
+static void
+parse_cpuinfo(long int *n_cores)
+{
+ static const char file_name[] = "/proc/cpuinfo";
+ char line[128];
+ uint64_t cpu = 0; /* Support up to 64 CPU packages on a single system. */
+ long int cores = 0;
+ FILE *stream;
+
+ stream = fopen(file_name, "r");
+ if (!stream) {
+ VLOG_DBG("%s: open failed (%s)", file_name, ovs_strerror(errno));
+ return;
+ }
+
+ while (fgets(line, sizeof line, stream)) {
+ unsigned int id;
+
+ /* Find the next CPU package. */
+ if (ovs_scan(line, "physical id%*[^:]: %u", &id)) {
+ if (id > 63) {
+ VLOG_WARN("Counted over 64 CPU packages on this system. "
+ "Parsing %s for core count may be inaccurate.",
+ file_name);
+ cores = 0;
+ break;
+ }
+
+ if (cpu & (1 << id)) {
+ /* We've already counted this package's cores. */
+ continue;
+ }
+ cpu |= 1 << id;
+
+ /* Find the number of cores for this package. */
+ while (fgets(line, sizeof line, stream)) {
+ int count;
+
+ if (ovs_scan(line, "cpu cores%*[^:]: %u", &count)) {
+ cores += count;
+ break;
+ }
+ }
+ }
+ }
+ fclose(stream);
+
+ *n_cores = cores;
+}
+
+/* Returns the total number of cores on this system, or 0 if the number cannot
+ * be determined.
+ *
+ * Tries not to count hyper-threads, but may be inaccurate - particularly on
+ * platforms that do not provide /proc/cpuinfo, but also if /proc/cpuinfo is
+ * formatted different to the layout that parse_cpuinfo() expects. */
+int
+count_cpu_cores(void)
+{
+ static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+ static long int n_cores;
+
+ if (ovsthread_once_start(&once)) {
+ parse_cpuinfo(&n_cores);
+ if (!n_cores) {
+ n_cores = sysconf(_SC_NPROCESSORS_ONLN);
+ }
+ ovsthread_once_done(&once);
+ }
+
+ return n_cores > 0 ? n_cores : 0;
+}
+\f
+/* ovsthread_key. */
+
+#define L1_SIZE 1024
+#define L2_SIZE 1024
+#define MAX_KEYS (L1_SIZE * L2_SIZE)
+
+/* A piece of thread-specific data. */
+struct ovsthread_key {
+ struct list list_node; /* In 'inuse_keys' or 'free_keys'. */
+ void (*destructor)(void *); /* Called at thread exit. */
+
+ /* Indexes into the per-thread array in struct ovsthread_key_slots.
+ * This key's data is stored in p1[index / L2_SIZE][index % L2_SIZE]. */
+ unsigned int index;
+};
+
+/* Per-thread data structure. */
+struct ovsthread_key_slots {
+ struct list list_node; /* In 'slots_list'. */
+ void **p1[L1_SIZE];
+};
+
+/* Contains "struct ovsthread_key_slots *". */
+static pthread_key_t tsd_key;
+
+/* Guards data structures below. */
+static struct ovs_mutex key_mutex = OVS_MUTEX_INITIALIZER;
+
+/* 'inuse_keys' holds "struct ovsthread_key"s that have been created and not
+ * yet destroyed.
+ *
+ * 'free_keys' holds "struct ovsthread_key"s that have been deleted and are
+ * ready for reuse. (We keep them around only to be able to easily locate
+ * free indexes.)
+ *
+ * Together, 'inuse_keys' and 'free_keys' hold an ovsthread_key for every index
+ * from 0 to n_keys - 1, inclusive. */
+static struct list inuse_keys OVS_GUARDED_BY(key_mutex)
+ = LIST_INITIALIZER(&inuse_keys);
+static struct list free_keys OVS_GUARDED_BY(key_mutex)
+ = LIST_INITIALIZER(&free_keys);
+static unsigned int n_keys OVS_GUARDED_BY(key_mutex);
+
+/* All existing struct ovsthread_key_slots. */
+static struct list slots_list OVS_GUARDED_BY(key_mutex)
+ = LIST_INITIALIZER(&slots_list);
+
+static void *
+clear_slot(struct ovsthread_key_slots *slots, unsigned int index)
+{
+ void **p2 = slots->p1[index / L2_SIZE];
+ if (p2) {
+ void **valuep = &p2[index % L2_SIZE];
+ void *value = *valuep;
+ *valuep = NULL;
+ return value;
+ } else {
+ return NULL;
+ }
+}
+
+static void
+ovsthread_key_destruct__(void *slots_)
+{
+ struct ovsthread_key_slots *slots = slots_;
+ struct ovsthread_key *key;
+ unsigned int n;
+ int i;
+
+ ovs_mutex_lock(&key_mutex);
+ list_remove(&slots->list_node);
+ LIST_FOR_EACH (key, list_node, &inuse_keys) {
+ void *value = clear_slot(slots, key->index);
+ if (value && key->destructor) {
+ key->destructor(value);
+ }
+ }
+ n = n_keys;
+ ovs_mutex_unlock(&key_mutex);
+
+ for (i = 0; i < n / L2_SIZE; i++) {
+ free(slots->p1[i]);
+ }
+ free(slots);
+}
+
+/* Initializes '*keyp' as a thread-specific data key. The data items are
+ * initially null in all threads.
+ *
+ * If a thread exits with non-null data, then 'destructor', if nonnull, will be
+ * called passing the final data value as its argument. 'destructor' must not
+ * call any thread-specific data functions in this API.
+ *
+ * This function is similar to xpthread_key_create(). */
+void
+ovsthread_key_create(ovsthread_key_t *keyp, void (*destructor)(void *))
+{
+ static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+ struct ovsthread_key *key;
+
+ if (ovsthread_once_start(&once)) {
+ xpthread_key_create(&tsd_key, ovsthread_key_destruct__);
+ ovsthread_once_done(&once);
+ }
+
+ ovs_mutex_lock(&key_mutex);
+ if (list_is_empty(&free_keys)) {
+ key = xmalloc(sizeof *key);
+ key->index = n_keys++;
+ if (key->index >= MAX_KEYS) {
+ abort();
+ }
+ } else {
+ key = CONTAINER_OF(list_pop_back(&free_keys),
+ struct ovsthread_key, list_node);
+ }
+ list_push_back(&inuse_keys, &key->list_node);
+ key->destructor = destructor;
+ ovs_mutex_unlock(&key_mutex);
+
+ *keyp = key;
+}
+
+/* Frees 'key'. The destructor supplied to ovsthread_key_create(), if any, is
+ * not called.
+ *
+ * This function is similar to xpthread_key_delete(). */
+void
+ovsthread_key_delete(ovsthread_key_t key)
+{
+ struct ovsthread_key_slots *slots;
+
+ ovs_mutex_lock(&key_mutex);
+
+ /* Move 'key' from 'inuse_keys' to 'free_keys'. */
+ list_remove(&key->list_node);
+ list_push_back(&free_keys, &key->list_node);
+
+ /* Clear this slot in all threads. */
+ LIST_FOR_EACH (slots, list_node, &slots_list) {
+ clear_slot(slots, key->index);
+ }
+
+ ovs_mutex_unlock(&key_mutex);
+}
+
+static void **
+ovsthread_key_lookup__(const struct ovsthread_key *key)
+{
+ struct ovsthread_key_slots *slots;
+ void **p2;
+
+ slots = pthread_getspecific(tsd_key);
+ if (!slots) {
+ slots = xzalloc(sizeof *slots);
+
+ ovs_mutex_lock(&key_mutex);
+ pthread_setspecific(tsd_key, slots);
+ list_push_back(&slots_list, &slots->list_node);
+ ovs_mutex_unlock(&key_mutex);
+ }
+
+ p2 = slots->p1[key->index / L2_SIZE];
+ if (!p2) {
+ p2 = xzalloc(L2_SIZE * sizeof *p2);
+ slots->p1[key->index / L2_SIZE] = p2;
+ }
+
+ return &p2[key->index % L2_SIZE];
+}
+
+/* Sets the value of thread-specific data item 'key', in the current thread, to
+ * 'value'.
+ *
+ * This function is similar to pthread_setspecific(). */
+void
+ovsthread_setspecific(ovsthread_key_t key, const void *value)
+{
+ *ovsthread_key_lookup__(key) = CONST_CAST(void *, value);
+}
+
+/* Returns the value of thread-specific data item 'key' in the current thread.
+ *
+ * This function is similar to pthread_getspecific(). */
+void *
+ovsthread_getspecific(ovsthread_key_t key)
+{
+ return *ovsthread_key_lookup__(key);
+}
#endif
projects / cascardo / ovs.git / blobdiff