git: 894f70a2bd8c - main - libthr: drop use of try_gc in the end of thr_join

The branch main has been updated by aokblast:

URL: https://cgit.FreeBSD.org/src/commit/?id=894f70a2bd8c7f67f131b76b9ce122a752818af3

commit 894f70a2bd8c7f67f131b76b9ce122a752818af3
Author:     ShengYi Hung <aokblast@FreeBSD.org>
AuthorDate: 2026-10-13 22:40:05 +0000
Commit:     ShengYi Hung <aokblast@FreeBSD.org>
CommitDate: 2026-10-19 05:23:14 +0000

    libthr: drop use of try_gc in the end of thr_join
    
    thr_try_gc unlock and lock again to make sure the lock order. However,
    there is no reason for such roundtrip if the caller holds the correct
    oder. As a result, we create a new helper function to add the thread
    to gc list without unlock + lock and wire the join_common to this new helper.
    
    Reviewed by:    kib
    MFC after:      2 weeks
    Differential Revision: https://reviews.freebsd.org/D60717
---
 lib/libthr/thread/thr_join.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/lib/libthr/thread/thr_join.c b/lib/libthr/thread/thr_join.c
index 16137d482632..bc06390ebe58 100644
--- a/lib/libthr/thread/thr_join.c
+++ b/lib/libthr/thread/thr_join.c
@@ -92,19 +92,12 @@ _pthread_tryjoin_np(pthread_t pthread, void **thread_return)
 	return (join_common(pthread, thread_return, NULL, false, true));
 }
 
-static void
-join_common_joined(struct pthread *pthread, struct pthread *curthread,
-    void **thread_return)
+static void *
+join_common_detach(struct pthread *pthread)
 {
-	void *tmp;
-
-	tmp = pthread->ret;
 	pthread->flags |= THR_FLAGS_DETACHED;
 	pthread->joiner = NULL;
-	_thr_try_gc(curthread, pthread); /* thread lock released */
-
-	if (thread_return != NULL)
-		*thread_return = tmp;
+	return (pthread->ret);
 }
 
 /*
@@ -117,6 +110,7 @@ join_common(pthread_t pthread, void **thread_return,
 {
 	struct pthread *curthread = _get_curthread();
 	struct timespec ts, ts2, *tsp;
+	void *tmp;
 	long tid;
 	int ret;
 
@@ -156,7 +150,10 @@ join_common(pthread_t pthread, void **thread_return,
 			THR_THREAD_UNLOCK(curthread, pthread);
 			return (EBUSY);
 		}
-		join_common_joined(pthread, curthread, thread_return);
+		tmp = join_common_detach(pthread);
+		_thr_try_gc(curthread, pthread); /* thread lock released */
+		if (thread_return != NULL)
+			*thread_return = tmp;
 		return (0);
 	}
 
@@ -193,8 +190,17 @@ join_common(pthread_t pthread, void **thread_return,
 		backout_join(pthread, curthread);
 	} else {
 		ret = 0;
+		THREAD_LIST_WRLOCK(curthread);
 		THR_THREAD_LOCK(curthread, pthread);
-		join_common_joined(pthread, curthread, thread_return);
+		tmp = join_common_detach(pthread);
+		if (THR_SHOULD_GC(pthread)) {
+			THR_LIST_REMOVE(pthread);
+			THR_GCLIST_ADD(pthread);
+		}
+		THR_THREAD_UNLOCK(curthread, pthread);
+		THREAD_LIST_UNLOCK(curthread);
+		if (thread_return != NULL)
+			*thread_return = tmp;
 	}
 	return (ret);
 }