Set TASKQ_DYNAMIC for kmem and system taskqs

Add the TASKQ_DYNAMIC flag to the kmem_cache and system taskqs to reduce the number of idle threads on the system. Additional threads will be created on demand up to the previous maximum thread counts. This should have minimal, if any, impact on performance. This makes the system taskq consistent with illumos which is always created as a dynamic taskq with up to 64 threads. The task limits for the kmem_cache have been increased to avoid any unnessisary throttling and to keep a larger reserve of task_t structures on the free list. Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: Tim Chase <[email protected]> Closes openzfs#458
behlendorf · Jun 24, 2015 · 3c82160 · 3c82160
1 parent f7a973d
commit 3c82160
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diff --git a/module/spl/spl-kmem-cache.c b/module/spl/spl-kmem-cache.c
@@ -1725,7 +1725,9 @@ spl_kmem_cache_init(void)
 	init_rwsem(&spl_kmem_cache_sem);
 	INIT_LIST_HEAD(&spl_kmem_cache_list);
 	spl_kmem_cache_taskq = taskq_create("spl_kmem_cache",
-	    spl_kmem_cache_kmem_threads, maxclsyspri, 1, 32, TASKQ_PREPOPULATE);
+	    spl_kmem_cache_kmem_threads, maxclsyspri,
+	    spl_kmem_cache_kmem_threads * 8, INT_MAX,
+	    TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
 	spl_register_shrinker(&spl_kmem_cache_shrinker);
 
 	return (0);

diff --git a/module/spl/spl-taskq.c b/module/spl/spl-taskq.c
@@ -1069,10 +1069,8 @@ EXPORT_SYMBOL(taskq_destroy);
 int
 spl_taskq_init(void)
 {
-	/* Solaris creates a dynamic taskq of up to 64 threads, however in
-	 * a Linux environment 1 thread per-core is usually about right */
-	system_taskq = taskq_create("spl_system_taskq", num_online_cpus(),
-				    minclsyspri, 4, 512, TASKQ_PREPOPULATE);
+	system_taskq = taskq_create("spl_system_taskq", MAX(boot_ncpus, 64),
+	    minclsyspri, boot_ncpus, INT_MAX, TASKQ_PREPOPULATE|TASKQ_DYNAMIC);
 	if (system_taskq == NULL)
 		return (1);