Introduce names for ZTHRs

When debugging issues or generally analyzing the runtime of
a system it would be nice to be able to tell the different
ZTHRs running by name rather than having to analyze their
stack.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Matthew Ahrens <[email protected]>
Co-authored-by: Ryan Moeller <[email protected]>
Signed-off-by: Serapheim Dimitropoulos <[email protected]>
Closes #10630 

4 files changed, 24 insertions, 16 deletions

diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 785ad9775..9e9227271 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -7339,10 +7339,10 @@ arc_init(void)
 		kstat_install(arc_ksp);
 	}
 
-	arc_evict_zthr = zthr_create_timer(arc_evict_cb_check,
-	    arc_evict_cb, NULL, SEC2NSEC(1));
-	arc_reap_zthr = zthr_create_timer(arc_reap_cb_check,
-	    arc_reap_cb, NULL, SEC2NSEC(1));
+	arc_evict_zthr = zthr_create_timer("arc_evict",
+	    arc_evict_cb_check, arc_evict_cb, NULL, SEC2NSEC(1));
+	arc_reap_zthr = zthr_create_timer("arc_reap",
+	    arc_reap_cb_check, arc_reap_cb, NULL, SEC2NSEC(1));
 
 	arc_warm = B_FALSE;
 
diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index 2783e9e29..86e5d0125 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -2548,7 +2548,8 @@ static void
 spa_start_livelist_destroy_thread(spa_t *spa)
 {
 	ASSERT3P(spa->spa_livelist_delete_zthr, ==, NULL);
-	spa->spa_livelist_delete_zthr = zthr_create(
+	spa->spa_livelist_delete_zthr =
+	    zthr_create("z_livelist_destroy",
 	    spa_livelist_delete_cb_check, spa_livelist_delete_cb, spa);
 }
 
@@ -2755,8 +2756,10 @@ spa_start_livelist_condensing_thread(spa_t *spa)
 	spa->spa_to_condense.cancelled = B_FALSE;
 
 	ASSERT3P(spa->spa_livelist_condense_zthr, ==, NULL);
-	spa->spa_livelist_condense_zthr = zthr_create(
-	    spa_livelist_condense_cb_check, spa_livelist_condense_cb, spa);
+	spa->spa_livelist_condense_zthr =
+	    zthr_create("z_livelist_condense",
+	    spa_livelist_condense_cb_check,
+	    spa_livelist_condense_cb, spa);
 }
 
 static void
@@ -2772,7 +2775,8 @@ spa_spawn_aux_threads(spa_t *spa)
 
 	ASSERT3P(spa->spa_checkpoint_discard_zthr, ==, NULL);
 	spa->spa_checkpoint_discard_zthr =
-	    zthr_create(spa_checkpoint_discard_thread_check,
+	    zthr_create("z_checkpoint_discard",
+	    spa_checkpoint_discard_thread_check,
 	    spa_checkpoint_discard_thread, spa);
 }
 
diff --git a/module/zfs/vdev_indirect.c b/module/zfs/vdev_indirect.c
index ac3e13d37..fc49bad06 100644
--- a/module/zfs/vdev_indirect.c
+++ b/module/zfs/vdev_indirect.c
@@ -884,7 +884,8 @@ void
 spa_start_indirect_condensing_thread(spa_t *spa)
 {
 	ASSERT3P(spa->spa_condense_zthr, ==, NULL);
-	spa->spa_condense_zthr = zthr_create(spa_condense_indirect_thread_check,
+	spa->spa_condense_zthr = zthr_create("z_indirect_condense",
+	    spa_condense_indirect_thread_check,
 	    spa_condense_indirect_thread, spa);
 }
 
diff --git a/module/zfs/zthr.c b/module/zfs/zthr.c
index 53c0a0b3d..fdc4b8633 100644
--- a/module/zfs/zthr.c
+++ b/module/zfs/zthr.c
@@ -14,7 +14,7 @@
  */
 
 /*
- * Copyright (c) 2017, 2019 by Delphix. All rights reserved.
+ * Copyright (c) 2017, 2020 by Delphix. All rights reserved.
  */
 
 /*
@@ -269,9 +269,11 @@ zthr_procedure(void *arg)
 }
 
 zthr_t *
-zthr_create(zthr_checkfunc_t *checkfunc, zthr_func_t *func, void *arg)
+zthr_create(const char *zthr_name, zthr_checkfunc_t *checkfunc,
+    zthr_func_t *func, void *arg)
 {
-	return (zthr_create_timer(checkfunc, func, arg, (hrtime_t)0));
+	return (zthr_create_timer(zthr_name, checkfunc,
+	    func, arg, (hrtime_t)0));
 }
 
 /*
@@ -280,8 +282,8 @@ zthr_create(zthr_checkfunc_t *checkfunc, zthr_func_t *func, void *arg)
  * start working if required) will be triggered.
  */
 zthr_t *
-zthr_create_timer(zthr_checkfunc_t *checkfunc, zthr_func_t *func,
-    void *arg, hrtime_t max_sleep)
+zthr_create_timer(const char *zthr_name, zthr_checkfunc_t *checkfunc,
+    zthr_func_t *func, void *arg, hrtime_t max_sleep)
 {
 	zthr_t *t = kmem_zalloc(sizeof (*t), KM_SLEEP);
 	mutex_init(&t->zthr_state_lock, NULL, MUTEX_DEFAULT, NULL);
@@ -295,8 +297,9 @@ zthr_create_timer(zthr_checkfunc_t *checkfunc, zthr_func_t *func,
 	t->zthr_arg = arg;
 	t->zthr_sleep_timeout = max_sleep;
 
-	t->zthr_thread = thread_create(NULL, 0, zthr_procedure, t,
-	    0, &p0, TS_RUN, minclsyspri);
+	t->zthr_thread = thread_create_named(zthr_name, NULL, 0,
+	    zthr_procedure, t, 0, &p0, TS_RUN, minclsyspri);
+
 	mutex_exit(&t->zthr_state_lock);
 
 	return (t);