UBUNTU: SAUCE: (noup) Update zfs to 0.7.5-1ubuntu16.6

[mirror_ubuntu-bionic-kernel.git] / zfs / module / zfs / spa.c

diff --git a/zfs/module/zfs/spa.c b/zfs/module/zfs/spa.c
index 00587d8e88d1cee7b94220006bfafe7061d5de7c..b777afc60242964ee556f99c98d3381f55c7079a 100644 (file)
--- a/zfs/module/zfs/spa.c
+++ b/zfs/module/zfs/spa.c
@@ -1182,6 +1182,14 @@ spa_activate(spa_t *spa, int mode)
        spa->spa_zvol_taskq = taskq_create("z_zvol", 1, defclsyspri,
            1, INT_MAX, 0);
 
+       /*
+        * Taskq dedicated to prefetcher threads: this is used to prevent the
+        * pool traverse code from monopolizing the global (and limited)
+        * system_taskq by inappropriately scheduling long running tasks on it.
+        */
+       spa->spa_prefetch_taskq = taskq_create("z_prefetch", boot_ncpus,
+           defclsyspri, 1, INT_MAX, TASKQ_DYNAMIC);
+
        /*
         * The taskq to upgrade datasets in this pool. Currently used by
         * feature SPA_FEATURE_USEROBJ_ACCOUNTING.
@@ -1211,6 +1219,11 @@ spa_deactivate(spa_t *spa)
                spa->spa_zvol_taskq = NULL;
        }
 
+       if (spa->spa_prefetch_taskq) {
+               taskq_destroy(spa->spa_prefetch_taskq);
+               spa->spa_prefetch_taskq = NULL;
+       }
+
        if (spa->spa_upgrade_taskq) {
                taskq_destroy(spa->spa_upgrade_taskq);
                spa->spa_upgrade_taskq = NULL;