lc = 0;
- emc_cache_slow_sweep(&pmd->flow_cache);
coverage_try_clear();
- ovsrcu_quiesce();
+ if (!ovsrcu_try_quiesce()) {
+ emc_cache_slow_sweep(&pmd->flow_cache);
+ }
atomic_read_relaxed(&pmd->change_seq, &seq);
if (seq != port_seq) {
*/
#include <config.h>
+#include <errno.h>
#include "ovs-rcu.h"
#include "fatal-signal.h"
#include "guarded-list.h"
static struct seq *flushed_cbsets_seq;
static void ovsrcu_init_module(void);
+static void ovsrcu_flush_cbset__(struct ovsrcu_perthread *, bool);
static void ovsrcu_flush_cbset(struct ovsrcu_perthread *);
static void ovsrcu_unregister__(struct ovsrcu_perthread *);
static bool ovsrcu_call_postponed(void);
ovsrcu_quiesced();
}
+int
+ovsrcu_try_quiesce(void)
+{
+ struct ovsrcu_perthread *perthread;
+ int ret = EBUSY;
+
+ ovs_assert(!single_threaded());
+ perthread = ovsrcu_perthread_get();
+ if (!seq_try_lock()) {
+ perthread->seqno = seq_read_protected(global_seqno);
+ if (perthread->cbset) {
+ ovsrcu_flush_cbset__(perthread, true);
+ }
+ seq_change_protected(global_seqno);
+ seq_unlock();
+ ovsrcu_quiesced();
+ ret = 0;
+ }
+ return ret;
+}
+
bool
ovsrcu_is_quiescent(void)
{
}
static void
-ovsrcu_flush_cbset(struct ovsrcu_perthread *perthread)
+ovsrcu_flush_cbset__(struct ovsrcu_perthread *perthread, bool protected)
{
struct ovsrcu_cbset *cbset = perthread->cbset;
guarded_list_push_back(&flushed_cbsets, &cbset->list_node, SIZE_MAX);
perthread->cbset = NULL;
- seq_change(flushed_cbsets_seq);
+ if (protected) {
+ seq_change_protected(flushed_cbsets_seq);
+ } else {
+ seq_change(flushed_cbsets_seq);
+ }
}
}
+static void
+ovsrcu_flush_cbset(struct ovsrcu_perthread *perthread)
+{
+ ovsrcu_flush_cbset__(perthread, false);
+}
+
static void
ovsrcu_unregister__(struct ovsrcu_perthread *perthread)
{
void ovsrcu_quiesce_start(void);
void ovsrcu_quiesce_end(void);
void ovsrcu_quiesce(void);
+int ovsrcu_try_quiesce(void);
bool ovsrcu_is_quiescent(void);
/* Synchronization. Waits for all non-quiescent threads to quiesce at least
ovs_mutex_unlock(&seq_mutex);
}
+int
+seq_try_lock(void)
+{
+ return ovs_mutex_trylock(&seq_mutex);
+}
+
+void
+seq_lock(void)
+ OVS_ACQUIRES(seq_mutex)
+{
+ ovs_mutex_lock(&seq_mutex);
+}
+
+void
+seq_unlock(void)
+ OVS_RELEASES(seq_mutex)
+{
+ ovs_mutex_unlock(&seq_mutex);
+}
+
/* Increments 'seq''s sequence number, waking up any threads that are waiting
* on 'seq'. */
void
-seq_change(struct seq *seq)
- OVS_EXCLUDED(seq_mutex)
+seq_change_protected(struct seq *seq)
+ OVS_REQUIRES(seq_mutex)
{
COVERAGE_INC(seq_change);
- ovs_mutex_lock(&seq_mutex);
seq->value = seq_next++;
seq_wake_waiters(seq);
+}
+
+/* Increments 'seq''s sequence number, waking up any threads that are waiting
+ * on 'seq'. */
+void
+seq_change(struct seq *seq)
+ OVS_EXCLUDED(seq_mutex)
+{
+ ovs_mutex_lock(&seq_mutex);
+ seq_change_protected(seq);
ovs_mutex_unlock(&seq_mutex);
}
+/* Returns 'seq''s current sequence number (which could change immediately).
+ *
+ * seq_read() and seq_wait() can be used together to yield a race-free wakeup
+ * when an object changes, even without an ability to lock the object. See
+ * Usage in seq.h for details. */
+uint64_t
+seq_read_protected(const struct seq *seq)
+ OVS_REQUIRES(seq_mutex)
+{
+ return seq->value;
+}
+
/* Returns 'seq''s current sequence number (which could change immediately).
*
* seq_read() and seq_wait() can be used together to yield a race-free wakeup
uint64_t value;
ovs_mutex_lock(&seq_mutex);
- value = seq->value;
+ value = seq_read_protected(seq);
ovs_mutex_unlock(&seq_mutex);
return value;
struct seq *seq_create(void);
void seq_destroy(struct seq *);
void seq_change(struct seq *);
+void seq_change_protected(struct seq *);
+void seq_lock(void);
+int seq_try_lock(void);
+void seq_unlock(void);
/* For observers. */
uint64_t seq_read(const struct seq *);
+uint64_t seq_read_protected(const struct seq *);
void seq_wait_at(const struct seq *, uint64_t value, const char *where);
#define seq_wait(seq, value) seq_wait_at(seq, value, OVS_SOURCE_LOCATOR)