Improve write issue taskqs utilization

[mirror_zfs.git] / module / zfs / spa_misc.c

diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index 5fb7847b5d8b5ef94c780ab29cb936356aa13b38..e6d4a9bdb29c3b73b522064ad62e8dc3cc480cc5 100644 (file)
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -394,6 +394,7 @@ static const uint64_t spa_max_slop = 128ULL * 1024 * 1024 * 1024;
  * Number of allocators to use, per spa instance
  */
 static int spa_num_allocators = 4;
+static int spa_cpus_per_allocator = 4;
 
 /*
  * Spa active allocator.
@@ -747,8 +748,9 @@ spa_add(const char *name, nvlist_t *config, const char *altroot)
        if (altroot)
                spa->spa_root = spa_strdup(altroot);
 
-       /* Do not allow more allocators than CPUs. */
-       spa->spa_alloc_count = MIN(MAX(spa_num_allocators, 1), boot_ncpus);
+       /* Do not allow more allocators than fraction of CPUs. */
+       spa->spa_alloc_count = MAX(MIN(spa_num_allocators,
+           boot_ncpus / MAX(spa_cpus_per_allocator, 1)), 1);
 
        spa->spa_allocs = kmem_zalloc(spa->spa_alloc_count *
            sizeof (spa_alloc_t), KM_SLEEP);
@@ -758,6 +760,12 @@ spa_add(const char *name, nvlist_t *config, const char *altroot)
                avl_create(&spa->spa_allocs[i].spaa_tree, zio_bookmark_compare,
                    sizeof (zio_t), offsetof(zio_t, io_queue_node.a));
        }
+       if (spa->spa_alloc_count > 1) {
+               spa->spa_allocs_use = kmem_zalloc(offsetof(spa_allocs_use_t,
+                   sau_inuse[spa->spa_alloc_count]), KM_SLEEP);
+               mutex_init(&spa->spa_allocs_use->sau_lock, NULL, MUTEX_DEFAULT,
+                   NULL);
+       }
 
        avl_create(&spa->spa_metaslabs_by_flushed, metaslab_sort_by_flushed,
            sizeof (metaslab_t), offsetof(metaslab_t, ms_spa_txg_node));
@@ -853,6 +861,11 @@ spa_remove(spa_t *spa)
        }
        kmem_free(spa->spa_allocs, spa->spa_alloc_count *
            sizeof (spa_alloc_t));
+       if (spa->spa_alloc_count > 1) {
+               mutex_destroy(&spa->spa_allocs_use->sau_lock);
+               kmem_free(spa->spa_allocs_use, offsetof(spa_allocs_use_t,
+                   sau_inuse[spa->spa_alloc_count]));
+       }
 
        avl_destroy(&spa->spa_metaslabs_by_flushed);
        avl_destroy(&spa->spa_sm_logs_by_txg);
@@ -3097,4 +3110,7 @@ ZFS_MODULE_PARAM_CALL(zfs_spa, spa_, slop_shift, param_set_slop_shift,
        param_get_uint, ZMOD_RW, "Reserved free space in pool");
 
 ZFS_MODULE_PARAM(zfs, spa_, num_allocators, INT, ZMOD_RW,
-       "Number of allocators per spa, capped by ncpus");
+       "Number of allocators per spa");
+
+ZFS_MODULE_PARAM(zfs, spa_, cpus_per_allocator, INT, ZMOD_RW,
+       "Minimum number of CPUs per allocators");