1 files changed, 37 insertions, 3 deletions

diff --git a/thrpool.c b/thrpool.c
index 00c4586..718c568 100644
--- a/thrpool.c
+++ b/thrpool.c
@@ -46,13 +46,38 @@ static void poke(pthread_t thr, int sig)
         assert(err == ESRCH && "pthread_kill() usage bug");
 }
 
+static bool
+thr_create_fail_retry(struct mog_thrpool *tp, size_t size,
+                      unsigned long *nr_eagain, int err)
+{
+        /* do not leave the pool w/o threads at all */
+        if (tp->n_threads == 0) {
+                if ((++*nr_eagain % 1024) == 0) {
+                        errno = err;
+                        syslog(LOG_ERR, "pthread_create: %m (tries: %lu)",
+                               *nr_eagain);
+                }
+                sched_yield();
+                return true;
+        } else {
+                errno = err;
+                syslog(LOG_ERR,
+                       "pthread_create: %m, only running %lu of %lu threads",
+                       (unsigned long)tp->n_threads, (unsigned long)size);
+                return false;
+        }
+}
+
 static void thrpool_set_size(struct mog_thrpool *tp, size_t size)
 {
+        unsigned long nr_eagain = 0;
+
         CHECK(int, 0, pthread_mutex_lock(&tp->lock));
         while (size > tp->n_threads) {
                 pthread_t *thr;
                 pthread_attr_t attr;
                 size_t bytes = (tp->n_threads + 1) * sizeof(pthread_t);
+                int rc;
 
                 tp->threads = xrealloc(tp->threads, bytes);
 
@@ -65,10 +90,18 @@ static void thrpool_set_size(struct mog_thrpool *tp, size_t size)
 
                 thr = tp->threads + tp->n_threads;
 
-                CHECK(int, 0,
-                      pthread_create(thr, &attr, tp->start_fn, tp->start_arg));
+                rc = pthread_create(thr, &attr, tp->start_fn, tp->start_arg);
                 CHECK(int, 0, pthread_attr_destroy(&attr));
-                tp->n_threads++;
+
+                if (rc == 0) {
+                        tp->n_threads++;
+                        nr_eagain = 0;
+                } else if (rc == EAGAIN) {
+                        if (!thr_create_fail_retry(tp, size, &nr_eagain, rc))
+                                goto out;
+                } else {
+                        assert(rc == 0 && "pthread_create usage error");
+                }
         }
 
         if (tp->n_threads > size) {
@@ -95,6 +128,7 @@ static void thrpool_set_size(struct mog_thrpool *tp, size_t size)
                 }
                 tp->n_threads = size;
         }
+out:
         CHECK(int, 0, pthread_mutex_unlock(&tp->lock));
 }