From: Jens Axboe <axboe@fb.com>
Date: Sun, 12 Jun 2016 03:27:29 +0000 (-0600)
Subject: Revert "fio: Simplify forking of processes"
X-Git-Tag: fio-2.12~4
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=cb92ecf8118b1a8b13909ab18d8a646e24ac79f2;hp=54d0a3150d44adca3ee4047fabd85651c6ea2db1;ds=sidebyside

Revert "fio: Simplify forking of processes"

This reverts commit d7982dd0ab2a1a315b5f9859c67a02414ce6274f.

Causes a regression in the logging, looks like a problem with
shared memory. Will need to investigate further, but it's
reproducibly broken.
---

diff --git a/backend.c b/backend.c
index d8f4f4cf..bb0200bb 100644
--- a/backend.c
+++ b/backend.c
@@ -1799,6 +1799,39 @@ err:
 	return (void *) (uintptr_t) td->error;
 }
 
+
+/*
+ * We cannot pass the td data into a forked process, so attach the td and
+ * pass it to the thread worker.
+ */
+static int fork_main(struct sk_out *sk_out, int shmid, int offset)
+{
+	struct fork_data *fd;
+	void *data, *ret;
+
+#if !defined(__hpux) && !defined(CONFIG_NO_SHM)
+	data = shmat(shmid, NULL, 0);
+	if (data == (void *) -1) {
+		int __err = errno;
+
+		perror("shmat");
+		return __err;
+	}
+#else
+	/*
+	 * HP-UX inherits shm mappings?
+	 */
+	data = threads;
+#endif
+
+	fd = calloc(1, sizeof(*fd));
+	fd->td = data + offset * sizeof(struct thread_data);
+	fd->sk_out = sk_out;
+	ret = thread_main(fd);
+	shmdt(data);
+	return (int) (uintptr_t) ret;
+}
+
 static void dump_td_info(struct thread_data *td)
 {
 	log_err("fio: job '%s' (state=%d) hasn't exited in %lu seconds, it "
@@ -2136,7 +2169,6 @@ reap:
 		struct thread_data *map[REAL_MAX_JOBS];
 		struct timeval this_start;
 		int this_jobs = 0, left;
-		struct fork_data *fd;
 
 		/*
 		 * create threads (TD_NOT_CREATED -> TD_CREATED)
@@ -2186,13 +2218,14 @@ reap:
 			map[this_jobs++] = td;
 			nr_started++;
 
-			fd = calloc(1, sizeof(*fd));
-			fd->td = td;
-			fd->sk_out = sk_out;
-
 			if (td->o.use_thread) {
+				struct fork_data *fd;
 				int ret;
 
+				fd = calloc(1, sizeof(*fd));
+				fd->td = td;
+				fd->sk_out = sk_out;
+
 				dprint(FD_PROCESS, "will pthread_create\n");
 				ret = pthread_create(&td->thread, NULL,
 							thread_main, fd);
@@ -2212,9 +2245,8 @@ reap:
 				dprint(FD_PROCESS, "will fork\n");
 				pid = fork();
 				if (!pid) {
-					int ret;
+					int ret = fork_main(sk_out, shm_id, i);
 
-					ret = (int)(uintptr_t)thread_main(fd);
 					_exit(ret);
 				} else if (i == fio_debug_jobno)
 					*fio_debug_jobp = pid;