env: Add a default value for mempool cache size

This is just a convenience and replaces the common practice
of passing -1.

Change-Id: Id96734307ebf52ef0ee7dba0e7ac89602b2b5b1a
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/374520
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

CHANGELOG.md

@@ -31,6 +31,13 @@ The NVMe driver now recognizes the NVMe 1.3 Namespace Optimal I/O Boundary field
 NVMe 1.3 devices may report an optimal I/O boundary, which the driver will take
 into account when splitting I/O requests.
 
+### Environment Abstraction Layer
+
+A new default value, SPDK_MEMPOOL_DEFAULT_CACHE_SIZE, was added to provide
+additional clarity when constructing spdk_mempools. Previously, -1 could be
+passed and the library would choose a reasonable default, but this new value
+makes it explicit that the default is being used.
+
 ## v17.07: Build system improvements, userspace vhost-blk target, and GPT bdev
 
 ### Build System

examples/ioat/perf/perf.c

@@ -468,9 +468,11 @@ associate_workers_with_chan(void)
 		t->ioat_chan_id = i;
 		snprintf(buf_pool_name, sizeof(buf_pool_name), "buf_pool_%d", i);
 		snprintf(task_pool_name, sizeof(task_pool_name), "task_pool_%d", i);
-		t->data_pool = spdk_mempool_create(buf_pool_name, 512, g_user_config.xfer_size_bytes, -1,
+		t->data_pool = spdk_mempool_create(buf_pool_name, 512, g_user_config.xfer_size_bytes,
+						   SPDK_MEMPOOL_DEFAULT_CACHE_SIZE,
 						   SPDK_ENV_SOCKET_ID_ANY);
-		t->task_pool = spdk_mempool_create(task_pool_name, 512, sizeof(struct ioat_task), -1,
+		t->task_pool = spdk_mempool_create(task_pool_name, 512, sizeof(struct ioat_task),
+						   SPDK_MEMPOOL_DEFAULT_CACHE_SIZE,
 						   SPDK_ENV_SOCKET_ID_ANY);
 		if (!t->data_pool || !t->task_pool) {
 			fprintf(stderr, "Could not allocate buffer pool.\n");

examples/ioat/verify/verify.c

@@ -332,10 +332,13 @@ work_fn(void *arg)
 
 	snprintf(buf_pool_name, sizeof(buf_pool_name), "buf_pool_%d", rte_lcore_id());
 	snprintf(task_pool_name, sizeof(task_pool_name), "task_pool_%d", rte_lcore_id());
-	t->data_pool = spdk_mempool_create(buf_pool_name, g_user_config.queue_depth, SRC_BUFFER_SIZE, -1,
+	t->data_pool = spdk_mempool_create(buf_pool_name, g_user_config.queue_depth, SRC_BUFFER_SIZE,
+					   SPDK_MEMPOOL_DEFAULT_CACHE_SIZE,
 					   SPDK_ENV_SOCKET_ID_ANY);
 	t->task_pool = spdk_mempool_create(task_pool_name, g_user_config.queue_depth,
-					   sizeof(struct ioat_task), -1, SPDK_ENV_SOCKET_ID_ANY);
+					   sizeof(struct ioat_task),
+					   SPDK_MEMPOOL_DEFAULT_CACHE_SIZE,
+					   SPDK_ENV_SOCKET_ID_ANY);
 	if (!t->data_pool || !t->task_pool) {
 		fprintf(stderr, "Could not allocate buffer pool.\n");
 		return 1;

include/spdk/env.h

@@ -137,11 +137,14 @@ void spdk_memzone_dump(FILE *f);
 
 struct spdk_mempool;
 
+#define SPDK_MEMPOOL_DEFAULT_CACHE_SIZE	SIZE_MAX
+
 /**
- * Create a thread-safe memory pool. Cache size is the number of
+ * Create a thread-safe memory pool.
- * elements in a thread-local cache. Can be 0 for no caching, or -1
- * for unspecified.
  *
+ * \param cache_size How many elements may be cached in per-core caches. Use
+ *        SPDK_MEMPOOL_DEFAULT_CACHE_SIZE for a reasonable default, or 0 for no
+ *	  per-core cache.
  * \param socket_id Socket ID to allocate memory on, or SPDK_ENV_SOCKET_ID_ANY for any socket.
  */
 struct spdk_mempool *spdk_mempool_create(const char *name, size_t count,

lib/blobfs/blobfs.c

@@ -197,7 +197,9 @@ __initialize_cache(void)
 
 	g_cache_pool = spdk_mempool_create("spdk_fs_cache",
 					   g_fs_cache_size / CACHE_BUFFER_SIZE,
-					   CACHE_BUFFER_SIZE, -1, SPDK_ENV_SOCKET_ID_ANY);
+					   CACHE_BUFFER_SIZE,
+					   SPDK_MEMPOOL_DEFAULT_CACHE_SIZE,
+					   SPDK_ENV_SOCKET_ID_ANY);
 	TAILQ_INIT(&g_caches);
 	pthread_spin_init(&g_caches_lock, 0);
 }

lib/event/reactor.c

@@ -559,7 +559,8 @@ spdk_reactors_init(unsigned int max_delay_us)
 			snprintf(mempool_name, sizeof(mempool_name), "evtpool%d_%d", i, getpid());
 			g_spdk_event_mempool[i] = spdk_mempool_create(mempool_name,
 						  (262144 / socket_count),
-						  sizeof(struct spdk_event), -1, i);
+						  sizeof(struct spdk_event),
+						  SPDK_MEMPOOL_DEFAULT_CACHE_SIZE, i);
 
 			if (g_spdk_event_mempool[i] == NULL) {
 				SPDK_ERRLOG("spdk_event_mempool creation failed on socket %d\n", i);
@@ -573,7 +574,8 @@ spdk_reactors_init(unsigned int max_delay_us)
 				g_spdk_event_mempool[i] = spdk_mempool_create(
 								  mempool_name,
 								  (262144 / socket_count),
-								  sizeof(struct spdk_event), -1,
+								  sizeof(struct spdk_event),
+								  SPDK_MEMPOOL_DEFAULT_CACHE_SIZE,
 								  SPDK_ENV_SOCKET_ID_ANY);
 
 				if (g_spdk_event_mempool[i] == NULL) {