io_channel: allow user to provide a thread name

This moves the thread name setting code into the generic SPDK thread
setup code, so now all spdk_threads can be named, not just ones created
by the event framework.

Change-Id: I6c824cf4bcf12fe64a8e2fc7cdc2d6c949021e40
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/375220
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

CHANGELOG.md

@@ -50,6 +50,13 @@ makes it explicit that the default is being used.
 spdk_bs_io_readv_blob() and spdk_bs_io_writev_blob() were added to enable
 scattered payloads.
 
+### Event Framework
+
+The ability to set a thread name, previously only used by the reactor code, is
+now part of the `spdk_thread_allocate()` API.  Users may specify a thread name
+which will show up in tools like `gdb`.
+
+
 ## v17.07: Build system improvements, userspace vhost-blk target, and GPT bdev
 
 ### Build System

examples/bdev/fio_plugin/fio_plugin.c

@@ -196,7 +196,7 @@ spdk_fio_init_thread(struct thread_data *td)
 		return -1;
 	}
 
-	fio_thread->thread = spdk_allocate_thread(spdk_fio_send_msg, fio_thread);
+	fio_thread->thread = spdk_allocate_thread(spdk_fio_send_msg, fio_thread, "fio_thread");
 	if (!fio_thread->thread) {
 		spdk_ring_free(fio_thread->ring);
 		free(fio_thread);

include/spdk/io_channel.h

@@ -66,8 +66,12 @@ typedef void (*spdk_channel_for_each_cpl)(void *io_device, void *ctx);
  *          called on the same thread that spdk_allocate_thread
  *          was called from.
  * @param thread_ctx Context that will be passed to fn.
+ * @param name Human-readable name for the thread; can be retrieved with spdk_thread_get_name().
+ *             The string is copied, so the pointed-to data only needs to be valid during the
+ *             spdk_allocate_thread() call.  May be NULL to specify no name.
  */
-struct spdk_thread *spdk_allocate_thread(spdk_thread_pass_msg fn, void *thread_ctx);
+struct spdk_thread *spdk_allocate_thread(spdk_thread_pass_msg fn, void *thread_ctx,
+		const char *name);
 
 /**
  * \brief Releases any resources related to the calling thread for I/O channel allocation.
@@ -85,6 +89,11 @@ void spdk_free_thread(void);
  */
 struct spdk_thread *spdk_get_thread(void);
 
+/**
+ * \brief Get a thread's name.
+ */
+const char *spdk_thread_get_name(const struct spdk_thread *thread);
+
 /**
  * \brief Send a message to the given thread. The message
  * may be sent asynchronously - i.e. spdk_thread_send_msg

lib/event/reactor.c

@@ -36,14 +36,6 @@
 #include "spdk_internal/event.h"
 #include "spdk_internal/log.h"
 
-#ifdef __linux__
-#include <sys/prctl.h>
-#endif
-
-#ifdef __FreeBSD__
-#include <pthread_np.h>
-#endif
-
 #include "spdk/log.h"
 #include "spdk/io_channel.h"
 #include "spdk/env.h"
@@ -207,27 +199,6 @@ _spdk_event_queue_run_batch(struct spdk_reactor *reactor)
 	return count;
 }
 
-/**
- *
- * \brief Set current reactor thread name to "reactor <cpu #>".
- *
- * This makes the reactor threads distinguishable in top and gdb.
- */
-static void set_reactor_thread_name(uint32_t lcore)
-{
-	char thread_name[16];
-
-	snprintf(thread_name, sizeof(thread_name), "reactor_%u", lcore);
-
-#if defined(__linux__)
-	prctl(PR_SET_NAME, thread_name, 0, 0, 0);
-#elif defined(__FreeBSD__)
-	pthread_set_name_np(pthread_self(), thread_name);
-#else
-#error missing platform support for thread name
-#endif
-}
-
 static void
 spdk_poller_insert_timer(struct spdk_reactor *reactor, struct spdk_poller *poller, uint64_t now)
 {
@@ -335,9 +306,10 @@ _spdk_reactor_run(void *arg)
 	uint64_t		spin_cycles, sleep_cycles;
 	uint32_t		sleep_us;
 	uint32_t 		timer_poll_count;
+	char			thread_name[32];
 
-	spdk_allocate_thread(_spdk_reactor_send_msg, &reactor->lcore);
+	snprintf(thread_name, sizeof(thread_name), "reactor_%u", reactor->lcore);
-	set_reactor_thread_name(reactor->lcore);
+	spdk_allocate_thread(_spdk_reactor_send_msg, &reactor->lcore, thread_name);
 	SPDK_NOTICELOG("Reactor started on core %u on socket %u\n", reactor->lcore,
 		       reactor->socket_id);
 

lib/rocksdb/env_spdk.cc

@@ -440,7 +440,7 @@ _spdk_send_msg(spdk_thread_fn fn, void *ctx, void *thread_ctx)
 void SpdkInitializeThread(void)
 {
 	if (g_fs != NULL) {
-		spdk_allocate_thread(_spdk_send_msg, NULL);
+		spdk_allocate_thread(_spdk_send_msg, NULL, "spdk_rocksdb");
 		g_sync_args.channel = spdk_fs_alloc_io_channel_sync(g_fs);
 	}
 }
@@ -481,7 +481,6 @@ spdk_rocksdb_run(void *arg1, void *arg2)
 {
 	struct spdk_bdev *bdev;
 
-	pthread_setname_np(pthread_self(), "spdk");
 	bdev = spdk_bdev_get_by_name(g_bdev_name.c_str());
 
 	if (bdev == NULL) {

lib/util/io_channel.c

@@ -36,6 +36,14 @@
 #include "spdk/io_channel.h"
 #include "spdk/log.h"
 
+#ifdef __linux__
+#include <sys/prctl.h>
+#endif
+
+#ifdef __FreeBSD__
+#include <pthread_np.h>
+#endif
+
 static pthread_mutex_t g_devlist_mutex = PTHREAD_MUTEX_INITIALIZER;
 
 struct io_device {
@@ -72,6 +80,7 @@ struct spdk_thread {
 	void *thread_ctx;
 	TAILQ_HEAD(, spdk_io_channel) io_channels;
 	TAILQ_ENTRY(spdk_thread) tailq;
+	char *name;
 };
 
 static TAILQ_HEAD(, spdk_thread) g_threads = TAILQ_HEAD_INITIALIZER(g_threads);
@@ -94,8 +103,20 @@ _get_thread(void)
 	return NULL;
 }
 
+static void
+_set_thread_name(const char *thread_name)
+{
+#if defined(__linux__)
+	prctl(PR_SET_NAME, thread_name, 0, 0, 0);
+#elif defined(__FreeBSD__)
+	pthread_set_name_np(pthread_self(), thread_name);
+#else
+#error missing platform support for thread name
+#endif
+}
+
 struct spdk_thread *
-spdk_allocate_thread(spdk_thread_pass_msg fn, void *thread_ctx)
+spdk_allocate_thread(spdk_thread_pass_msg fn, void *thread_ctx, const char *name)
 {
 	struct spdk_thread *thread;
 
@@ -120,6 +141,10 @@ spdk_allocate_thread(spdk_thread_pass_msg fn, void *thread_ctx)
 	thread->thread_ctx = thread_ctx;
 	TAILQ_INIT(&thread->io_channels);
 	TAILQ_INSERT_TAIL(&g_threads, thread, tailq);
+	if (name) {
+		_set_thread_name(name);
+		thread->name = strdup(name);
+	}
 
 	pthread_mutex_unlock(&g_devlist_mutex);
 
@@ -141,6 +166,7 @@ spdk_free_thread(void)
 	}
 
 	TAILQ_REMOVE(&g_threads, thread, tailq);
+	free(thread->name);
 	free(thread);
 
 	pthread_mutex_unlock(&g_devlist_mutex);
@@ -163,6 +189,12 @@ spdk_get_thread(void)
 	return thread;
 }
 
+const char *
+spdk_thread_get_name(const struct spdk_thread *thread)
+{
+	return thread->name;
+}
+
 void
 spdk_thread_send_msg(const struct spdk_thread *thread, spdk_thread_fn fn, void *ctx)
 {

test/lib/blobfs/blobfs_async_ut/blobfs_async_ut.c

@@ -73,7 +73,7 @@ fs_init(void)
 	struct spdk_bs_dev *dev;
 
 	dev = init_dev();
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 
 	spdk_fs_init(dev, NULL, fs_op_with_handle_complete, NULL);
 	CU_ASSERT(g_fs != NULL);
@@ -117,7 +117,7 @@ fs_open(void)
 
 	dev = init_dev();
 	memset(name, 'a', sizeof(name) - 1);
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 
 	spdk_fs_init(dev, NULL, fs_op_with_handle_complete, NULL);
 	CU_ASSERT(g_fs != NULL);
@@ -186,7 +186,7 @@ fs_create(void)
 
 	dev = init_dev();
 	memset(name, 'a', sizeof(name) - 1);
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 
 	spdk_fs_init(dev, NULL, fs_op_with_handle_complete, NULL);
 	SPDK_CU_ASSERT_FATAL(g_fs != NULL);
@@ -225,7 +225,7 @@ fs_truncate(void)
 	struct spdk_bs_dev *dev;
 
 	dev = init_dev();
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 
 	spdk_fs_init(dev, NULL, fs_op_with_handle_complete, NULL);
 	SPDK_CU_ASSERT_FATAL(g_fs != NULL);
@@ -278,7 +278,7 @@ fs_rename(void)
 	struct spdk_bs_dev *dev;
 
 	dev = init_dev();
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 
 	spdk_fs_init(dev, NULL, fs_op_with_handle_complete, NULL);
 	SPDK_CU_ASSERT_FATAL(g_fs != NULL);
@@ -431,7 +431,7 @@ channel_ops(void)
 	struct spdk_io_channel *channel;
 
 	dev = init_dev();
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 
 	spdk_fs_init(dev, NULL, fs_op_with_handle_complete, NULL);
 	SPDK_CU_ASSERT_FATAL(g_fs != NULL);
@@ -459,7 +459,7 @@ channel_ops_sync(void)
 	struct spdk_io_channel *channel;
 
 	dev = init_dev();
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 
 	spdk_fs_init(dev, NULL, fs_op_with_handle_complete, NULL);
 	SPDK_CU_ASSERT_FATAL(g_fs != NULL);

test/lib/blobfs/blobfs_sync_ut/blobfs_sync_ut.c

@@ -158,7 +158,7 @@ cache_write(void)
 
 	ut_send_request(_fs_init, NULL);
 
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 	channel = spdk_fs_alloc_io_channel_sync(g_fs);
 
 	rc = spdk_fs_open_file(g_fs, channel, "testfile", SPDK_BLOBFS_OPEN_CREATE, &g_file);
@@ -196,7 +196,7 @@ cache_write_null_buffer(void)
 
 	ut_send_request(_fs_init, NULL);
 
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 	channel = spdk_fs_alloc_io_channel_sync(g_fs);
 
 	rc = spdk_fs_open_file(g_fs, channel, "testfile", SPDK_BLOBFS_OPEN_CREATE, &g_file);
@@ -227,7 +227,7 @@ fs_create_sync(void)
 
 	ut_send_request(_fs_init, NULL);
 
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 	channel = spdk_fs_alloc_io_channel_sync(g_fs);
 	CU_ASSERT(channel != NULL);
 
@@ -256,7 +256,7 @@ cache_append_no_cache(void)
 
 	ut_send_request(_fs_init, NULL);
 
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 	channel = spdk_fs_alloc_io_channel_sync(g_fs);
 
 	rc = spdk_fs_open_file(g_fs, channel, "testfile", SPDK_BLOBFS_OPEN_CREATE, &g_file);
@@ -298,7 +298,7 @@ spdk_thread(void *arg)
 {
 	struct ut_request *req;
 
-	spdk_allocate_thread(_fs_send_msg, NULL);
+	spdk_allocate_thread(_fs_send_msg, NULL, "thread0");
 
 	while (1) {
 		pthread_mutex_lock(&g_mutex);

test/unit/lib/blob/blob.c/blob_ut.c

@@ -1218,7 +1218,7 @@ int main(int argc, char **argv)
 	}
 
 	g_dev_buffer = calloc(1, DEV_BUFFER_SIZE);
-	spdk_allocate_thread(_bs_send_msg, NULL);
+	spdk_allocate_thread(_bs_send_msg, NULL, "thread0");
 	CU_basic_set_mode(CU_BRM_VERBOSE);
 	CU_basic_run_tests();
 	num_failures = CU_get_number_of_failures();

test/unit/lib/util/io_channel.c/io_channel_ut.c

@@ -46,7 +46,24 @@ _send_msg(spdk_thread_fn fn, void *ctx, void *thread_ctx)
 static void
 thread_alloc(void)
 {
-	spdk_allocate_thread(_send_msg, NULL);
+	struct spdk_thread *thread;
+	const char *name;
+
+	/* Create thread with no name */
+	spdk_allocate_thread(_send_msg, NULL, NULL);
+	thread = spdk_get_thread();
+	SPDK_CU_ASSERT_FATAL(thread != NULL);
+	name = spdk_thread_get_name(thread);
+	CU_ASSERT(name == NULL);
+	spdk_free_thread();
+
+	/* Create thread named "test_thread" */
+	spdk_allocate_thread(_send_msg, NULL, "test_thread");
+	thread = spdk_get_thread();
+	SPDK_CU_ASSERT_FATAL(thread != NULL);
+	name = spdk_thread_get_name(thread);
+	SPDK_CU_ASSERT_FATAL(name != NULL);
+	CU_ASSERT(strcmp(name, "test_thread") == 0);
 	spdk_free_thread();
 }
 
@@ -106,7 +123,7 @@ channel(void)
 	struct spdk_io_channel *ch1, *ch2;
 	void *ctx;
 
-	spdk_allocate_thread(_send_msg, NULL);
+	spdk_allocate_thread(_send_msg, NULL, "thread0");
 	spdk_io_device_register(&device1, create_cb_1, destroy_cb_1, sizeof(ctx1));
 	spdk_io_device_register(&device2, create_cb_2, destroy_cb_2, sizeof(ctx2));
 	spdk_io_device_register(&device3, create_cb_null, NULL, 0);