/*
- * Copyright (c) 2013, 2014 Nicira, Inc.
+ * Copyright (c) 2013, 2014, 2015 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <stdlib.h>
#include <unistd.h>
#include "compiler.h"
+#include "fatal-signal.h"
#include "hash.h"
+#include "list.h"
#include "netdev-dpdk.h"
#include "ovs-rcu.h"
#include "poll-loop.h"
* cut-and-paste. Since "sparse" is just a checker, not a compiler, it
* doesn't matter that we don't define them. */
#else
-#include "vlog.h"
+#include "openvswitch/vlog.h"
VLOG_DEFINE_THIS_MODULE(ovs_thread);
l->where = WHERE; \
error = pthread_##TYPE##_##FUN(&l->lock); \
if (OVS_UNLIKELY(error)) { \
- ovs_abort(error, "pthread_%s_%sfailed", #TYPE, #FUN); \
+ ovs_abort(error, "pthread_%s_%s failed", #TYPE, #FUN); \
} \
}
UNLOCK_FUNCTION(mutex, unlock, "<unlocked>");
ovs_barrier_init(struct ovs_barrier *barrier, uint32_t size)
{
barrier->size = size;
- atomic_init(&barrier->count, 0);
+ atomic_count_init(&barrier->count, 0);
barrier->seq = seq_create();
}
}
/* Makes the calling thread block on the 'barrier' until all
- * 'barrier->size' threads hit the barrier. */
+ * 'barrier->size' threads hit the barrier.
+ * ovs_barrier provides the necessary acquire-release semantics to make
+ * the effects of prior memory accesses of all the participating threads
+ * visible on return and to prevent the following memory accesses to be
+ * reordered before the ovs_barrier_block(). */
void
ovs_barrier_block(struct ovs_barrier *barrier)
{
uint64_t seq = seq_read(barrier->seq);
uint32_t orig;
- atomic_add(&barrier->count, 1, &orig);
+ orig = atomic_count_inc(&barrier->count);
if (orig + 1 == barrier->size) {
- atomic_store(&barrier->count, 0);
+ atomic_count_set(&barrier->count, 0);
+ /* seq_change() serves as a release barrier against the other threads,
+ * so the zeroed count is visible to them as they continue. */
seq_change(barrier->seq);
- }
-
- /* To prevent thread from waking up by other event,
- * keeps waiting for the change of 'barrier->seq'. */
- while (seq == seq_read(barrier->seq)) {
- seq_wait(barrier->seq, seq);
- poll_block();
+ } else {
+ /* To prevent thread from waking up by other event,
+ * keeps waiting for the change of 'barrier->seq'. */
+ while (seq == seq_read(barrier->seq)) {
+ seq_wait(barrier->seq, seq);
+ poll_block();
+ }
}
}
\f
static void *
ovsthread_wrapper(void *aux_)
{
- static atomic_uint next_id = ATOMIC_VAR_INIT(1);
+ static atomic_count next_id = ATOMIC_COUNT_INIT(1);
struct ovsthread_aux *auxp = aux_;
struct ovsthread_aux aux;
unsigned int id;
- atomic_add(&next_id, 1, &id);
+ id = atomic_count_inc(&next_id);
*ovsthread_id_get() = id;
aux = *auxp;
/* The order of the following calls is important, because
* ovsrcu_quiesce_end() saves a copy of the thread name. */
- set_subprogram_name("%s%u", aux.name, id);
+ char *subprogram_name = xasprintf("%s%u", aux.name, id);
+ set_subprogram_name(subprogram_name);
+ free(subprogram_name);
ovsrcu_quiesce_end();
- thread_set_nonpmd();
-
return aux.start(aux.arg);
}
+static void
+set_min_stack_size(pthread_attr_t *attr, size_t min_stacksize)
+{
+ size_t stacksize;
+ int error;
+
+ error = pthread_attr_getstacksize(attr, &stacksize);
+ if (error) {
+ ovs_abort(error, "pthread_attr_getstacksize failed");
+ }
+
+ if (stacksize < min_stacksize) {
+ error = pthread_attr_setstacksize(attr, min_stacksize);
+ if (error) {
+ ovs_abort(error, "pthread_attr_setstacksize failed");
+ }
+ }
+}
+
/* Starts a thread that calls 'start(arg)'. Sets the thread's name to 'name'
* (suffixed by its ovsthread_id()). Returns the new thread's pthread_t. */
pthread_t
aux->arg = arg;
ovs_strlcpy(aux->name, name, sizeof aux->name);
+ /* Some small systems use a default stack size as small as 80 kB, but OVS
+ * requires approximately 384 kB according to the following analysis:
+ * http://openvswitch.org/pipermail/dev/2016-January/065049.html
+ *
+ * We use 512 kB to give us some margin of error. */
+ pthread_attr_t attr;
+ pthread_attr_init(&attr);
+ set_min_stack_size(&attr, 512 * 1024);
+
error = pthread_create(&thread, NULL, ovsthread_wrapper, aux);
if (error) {
ovs_abort(error, "pthread_create failed");
}
+ pthread_attr_destroy(&attr);
return thread;
}
\f
ovsthread_once_start__(struct ovsthread_once *once)
{
ovs_mutex_lock(&once->mutex);
- if (!ovsthread_once_is_done__(once)) {
- return false;
+ /* Mutex synchronizes memory, so we get the current value of 'done'. */
+ if (!once->done) {
+ return true;
}
ovs_mutex_unlock(&once->mutex);
- return true;
+ return false;
}
void
ovsthread_once_done(struct ovsthread_once *once)
{
- atomic_store(&once->done, true);
+ /* We need release semantics here, so that the following store may not
+ * be moved ahead of any of the preceding initialization operations.
+ * A release atomic_thread_fence provides that prior memory accesses
+ * will not be reordered to take place after the following store. */
+ atomic_thread_fence(memory_order_release);
+ once->done = true;
ovs_mutex_unlock(&once->mutex);
}
\f
return n_cores > 0 ? n_cores : 0;
}
+
+/* Returns 'true' if current thread is PMD thread. */
+bool
+thread_is_pmd(void)
+{
+ const char *name = get_subprogram_name();
+ return !strncmp(name, "pmd", 3);
+}
+
\f
/* ovsthread_key. */
/* A piece of thread-specific data. */
struct ovsthread_key {
- struct list list_node; /* In 'inuse_keys' or 'free_keys'. */
+ struct ovs_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.
/* Per-thread data structure. */
struct ovsthread_key_slots {
- struct list list_node; /* In 'slots_list'. */
+ struct ovs_list list_node; /* In 'slots_list'. */
void **p1[L1_SIZE];
};
*
* 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 struct ovs_list inuse_keys OVS_GUARDED_BY(key_mutex)
+ = OVS_LIST_INITIALIZER(&inuse_keys);
+static struct ovs_list free_keys OVS_GUARDED_BY(key_mutex)
+ = OVS_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 struct ovs_list slots_list OVS_GUARDED_BY(key_mutex)
+ = OVS_LIST_INITIALIZER(&slots_list);
static void *
clear_slot(struct ovsthread_key_slots *slots, unsigned int index)
n = n_keys;
ovs_mutex_unlock(&key_mutex);
- for (i = 0; i < n / L2_SIZE; i++) {
+ for (i = 0; i < DIV_ROUND_UP(n, L2_SIZE); i++) {
free(slots->p1[i]);
}
free(slots);
}
+/* Cancels the callback to ovsthread_key_destruct__().
+ *
+ * Cancelling the call to the destructor during the main thread exit
+ * is needed while using pthreads-win32 library in Windows. It has been
+ * observed that in pthreads-win32, a call to the destructor during
+ * main thread exit causes undefined behavior. */
+static void
+ovsthread_cancel_ovsthread_key_destruct__(void *aux OVS_UNUSED)
+{
+ pthread_setspecific(tsd_key, NULL);
+}
+
/* Initializes '*keyp' as a thread-specific data key. The data items are
* initially null in all threads.
*
if (ovsthread_once_start(&once)) {
xpthread_key_create(&tsd_key, ovsthread_key_destruct__);
+ fatal_signal_add_hook(ovsthread_cancel_ovsthread_key_destruct__,
+ NULL, NULL, true);
ovsthread_once_done(&once);
}
projects / cascardo / ovs.git / blobdiff