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 <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Co-authored-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #10630

include/os/freebsd/spl/sys/proc.h

@@ -65,7 +65,7 @@ extern struct proc *zfsproc;
 
 static __inline kthread_t *
 do_thread_create(caddr_t stk, size_t stksize, void (*proc)(void *), void *arg,
-    size_t len, proc_t *pp, int state, pri_t pri)
+    size_t len, proc_t *pp, int state, pri_t pri, const char *name)
 {
 	kthread_t *td = NULL;
 	int error;
@@ -78,7 +78,7 @@ do_thread_create(caddr_t stk, size_t stksize, void (*proc)(void *), void *arg,
 	ASSERT(state == TS_RUN);
 
 	error = kproc_kthread_add(proc, arg, &zfsproc, &td,
-	    RFSTOPPED, stksize / PAGE_SIZE, "zfskern", "solthread %p", proc);
+	    RFSTOPPED, stksize / PAGE_SIZE, "zfskern", "%s", name);
 	if (error == 0) {
 		thread_lock(td);
 		sched_prio(td, pri);
@@ -90,8 +90,11 @@ do_thread_create(caddr_t stk, size_t stksize, void (*proc)(void *), void *arg,
 	return (td);
 }
 
+#define	thread_create_named(name, stk, stksize, proc, arg, len,	\
+    pp, state, pri) \
+	do_thread_create(stk, stksize, proc, arg, len, pp, state, pri, name)
 #define	thread_create(stk, stksize, proc, arg, len, pp, state, pri) \
-	do_thread_create(stk, stksize, proc, arg, len, pp, state, pri)
+	do_thread_create(stk, stksize, proc, arg, len, pp, state, pri, #proc)
 #define	thread_exit()	kthread_exit()
 
 int	uread(proc_t *, void *, size_t, uintptr_t);

include/os/linux/spl/sys/thread.h

@@ -45,6 +45,11 @@
 
 typedef void (*thread_func_t)(void *);
 
+#define	thread_create_named(name, stk, stksize, func, arg, len,	\
+    pp, state, pri)	\
+	__thread_create(stk, stksize, (thread_func_t)func,		\
+	name, arg, len, pp, state, pri)
+
 /* BEGIN CSTYLED */
 #define	thread_create(stk, stksize, func, arg, len, pp, state, pri)	\
 	__thread_create(stk, stksize, (thread_func_t)func,		\

include/sys/zfs_context.h

@@ -218,6 +218,9 @@ typedef pthread_t	kthread_t;
 #define	kpreempt(x)	yield()
 #define	getcomm()	"unknown"
 
+#define	thread_create_named(name, stk, stksize, func, arg, len, \
+    pp, state, pri)	\
+	zk_thread_create(func, arg, stksize, state)
 #define	thread_create(stk, stksize, func, arg, len, pp, state, pri)	\
 	zk_thread_create(func, arg, stksize, state)
 #define	thread_exit()	pthread_exit(NULL)

include/sys/zthr.h

@@ -24,10 +24,11 @@ typedef struct zthr zthr_t;
 typedef void (zthr_func_t)(void *, zthr_t *);
 typedef boolean_t (zthr_checkfunc_t)(void *, zthr_t *);
 
-extern zthr_t *zthr_create(zthr_checkfunc_t checkfunc,
-    zthr_func_t *func, void *arg);
-extern zthr_t *zthr_create_timer(zthr_checkfunc_t *checkfunc,
-    zthr_func_t *func, void *arg, hrtime_t nano_wait);
+extern zthr_t *zthr_create(const char *zthr_name,
+    zthr_checkfunc_t checkfunc, zthr_func_t *func, void *arg);
+extern zthr_t *zthr_create_timer(const char *zthr_name,
+    zthr_checkfunc_t *checkfunc, zthr_func_t *func, void *arg,
+	hrtime_t nano_wait);
 extern void zthr_destroy(zthr_t *t);
 
 extern void zthr_wakeup(zthr_t *t);

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;
 

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);
 }
 

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);
 }
 

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);