Merge branch 'mainstream'

[sliver-openvswitch.git] / lib / ovs-rcu.c

diff --git a/lib/ovs-rcu.c b/lib/ovs-rcu.c
index 1843ef5..7aed6db 100644 (file)
--- a/lib/ovs-rcu.c
+++ b/lib/ovs-rcu.c
@@ -21,6 +21,10 @@
 #include "ovs-thread.h"
 #include "poll-loop.h"
 #include "seq.h"
+#include "timeval.h"
+#include "vlog.h"
+
+VLOG_DEFINE_THIS_MODULE(ovs_rcu);
 
 struct ovsrcu_cb {
     void (*function)(void *aux);
@@ -34,11 +38,12 @@ struct ovsrcu_cbset {
 };
 
 struct ovsrcu_perthread {
-    struct list list_node;           /* In global list. */
+    struct list list_node;      /* In global list. */
 
     struct ovs_mutex mutex;
     uint64_t seqno;
     struct ovsrcu_cbset *cbset;
+    char name[16];              /* This thread's name. */
 };
 
 static struct seq *global_seqno;
@@ -66,10 +71,14 @@ ovsrcu_perthread_get(void)
 
     perthread = pthread_getspecific(perthread_key);
     if (!perthread) {
+        const char *name = get_subprogram_name();
+
         perthread = xmalloc(sizeof *perthread);
         ovs_mutex_init(&perthread->mutex);
         perthread->seqno = seq_read(global_seqno);
         perthread->cbset = NULL;
+        ovs_strlcpy(perthread->name, name[0] ? name : "main",
+                    sizeof perthread->name);
 
         ovs_mutex_lock(&ovsrcu_threads_mutex);
         list_push_back(&ovsrcu_threads, &perthread->list_node);
@@ -99,7 +108,7 @@ ovsrcu_quiesced(void)
     } else {
         static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
         if (ovsthread_once_start(&once)) {
-            xpthread_create(NULL, NULL, ovsrcu_postpone_thread, NULL);
+            ovs_thread_create("urcu", ovsrcu_postpone_thread, NULL);
             ovsthread_once_done(&once);
         }
     }
@@ -134,10 +143,19 @@ ovsrcu_quiesce(void)
     ovsrcu_quiesced();
 }
 
+bool
+ovsrcu_is_quiescent(void)
+{
+    ovsrcu_init();
+    return pthread_getspecific(perthread_key) == NULL;
+}
+
 static void
 ovsrcu_synchronize(void)
 {
+    unsigned int warning_threshold = 1000;
     uint64_t target_seqno;
+    long long int start;
 
     if (single_threaded()) {
         return;
@@ -145,15 +163,20 @@ ovsrcu_synchronize(void)
 
     target_seqno = seq_read(global_seqno);
     ovsrcu_quiesce_start();
+    start = time_msec();
 
     for (;;) {
         uint64_t cur_seqno = seq_read(global_seqno);
         struct ovsrcu_perthread *perthread;
+        char stalled_thread[16];
+        unsigned int elapsed;
         bool done = true;
 
         ovs_mutex_lock(&ovsrcu_threads_mutex);
         LIST_FOR_EACH (perthread, list_node, &ovsrcu_threads) {
             if (perthread->seqno <= target_seqno) {
+                ovs_strlcpy(stalled_thread, perthread->name,
+                            sizeof stalled_thread);
                 done = false;
                 break;
             }
@@ -164,6 +187,14 @@ ovsrcu_synchronize(void)
             break;
         }
 
+        elapsed = time_msec() - start;
+        if (elapsed >= warning_threshold) {
+            VLOG_WARN("blocked %u ms waiting for %s to quiesce",
+                      elapsed, stalled_thread);
+            warning_threshold *= 2;
+        }
+        poll_timer_wait_until(start + warning_threshold);
+
         seq_wait(global_seqno, cur_seqno);
         poll_block();
     }