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author | Dmitry Chagin <dchagin@FreeBSD.org> | 2021-07-29 09:43:07 +0000 |
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committer | Dmitry Chagin <dchagin@FreeBSD.org> | 2022-06-17 19:33:17 +0000 |
commit | 85f6b0c801abecd35a42d630fe3a2b6f301fc785 (patch) | |
tree | 2a97c7974399d70a770916a43e2d8f2c15825d2b | |
parent | 6d6fb6026d5f49c509531e926c328e83a8b8ae1f (diff) | |
download | src-85f6b0c801abecd35a42d630fe3a2b6f301fc785.tar.gz src-85f6b0c801abecd35a42d630fe3a2b6f301fc785.zip |
umtx: Add umtxq_requeue Linux emulation layer extension.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D31235
MFC after: 2 weeks
(cherry picked from commit 8e4d22c01d8f76ae144f32b4c5fac40451429891)
-rw-r--r-- | sys/kern/kern_umtx.c | 37 | ||||
-rw-r--r-- | sys/sys/umtxvar.h | 1 |
2 files changed, 38 insertions, 0 deletions
diff --git a/sys/kern/kern_umtx.c b/sys/kern/kern_umtx.c index 256c7e048ba5..1ffa14b7cadb 100644 --- a/sys/kern/kern_umtx.c +++ b/sys/kern/kern_umtx.c @@ -621,6 +621,43 @@ umtxq_signal_thread(struct umtx_q *uq) wakeup(uq); } +/* + * Wake up a maximum of n_wake threads that are waiting on an userland + * object identified by key. The remaining threads are removed from queue + * identified by key and added to the queue identified by key2 (requeued). + * The n_requeue specifies an upper limit on the number of threads that + * are requeued to the second queue. + */ +int +umtxq_requeue(struct umtx_key *key, int n_wake, struct umtx_key *key2, + int n_requeue) +{ + struct umtxq_queue *uh, *uh2; + struct umtx_q *uq, *uq_temp; + int ret; + + ret = 0; + UMTXQ_LOCKED_ASSERT(umtxq_getchain(key)); + UMTXQ_LOCKED_ASSERT(umtxq_getchain(key2)); + uh = umtxq_queue_lookup(key, UMTX_SHARED_QUEUE); + uh2 = umtxq_queue_lookup(key2, UMTX_SHARED_QUEUE); + if (uh == NULL) + return (0); + TAILQ_FOREACH_SAFE(uq, &uh->head, uq_link, uq_temp) { + if (++ret <= n_wake) { + umtxq_remove(uq); + wakeup_one(uq); + } else { + umtxq_remove(uq); + uq->uq_key = *key2; + umtxq_insert(uq); + if (ret - n_wake == n_requeue) + break; + } + } + return (ret); +} + static inline int tstohz(const struct timespec *tsp) { diff --git a/sys/sys/umtxvar.h b/sys/sys/umtxvar.h index de1b649ed8d7..ed2d8046a5fb 100644 --- a/sys/sys/umtxvar.h +++ b/sys/sys/umtxvar.h @@ -210,6 +210,7 @@ void umtxq_free(struct umtx_q *); struct umtxq_chain *umtxq_getchain(struct umtx_key *); void umtxq_insert_queue(struct umtx_q *, int); void umtxq_remove_queue(struct umtx_q *, int); +int umtxq_requeue(struct umtx_key *, int, struct umtx_key *, int); int umtxq_signal_mask(struct umtx_key *, int, u_int); int umtxq_sleep(struct umtx_q *, const char *, struct umtx_abs_timeout *); |