diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2024-10-09 16:53:34 -0700 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2024-10-14 12:52:40 +0200 |
| commit | 894d1b3db41cf7e6ae0304429a1747b3c3f390bc (patch) | |
| tree | 3bcda09ee457a5edb2df9b51bbdfa04377394150 /kernel/locking/mutex.c | |
| parent | 7e019dcc470f27066c98697e43d930df8d54bd9c (diff) | |
locking/mutex: Remove wakeups from under mutex::wait_lock
In preparation to nest mutex::wait_lock under rq::lock we need
to remove wakeups from under it.
Do this by utilizing wake_qs to defer the wakeup until after the
lock is dropped.
[Heavily changed after 55f036ca7e74 ("locking: WW mutex cleanup") and
08295b3b5bee ("locking: Implement an algorithm choice for Wound-Wait
mutexes")]
[jstultz: rebased to mainline, added extra wake_up_q & init
to avoid hangs, similar to Connor's rework of this patch]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Metin Kaya <metin.kaya@arm.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: Metin Kaya <metin.kaya@arm.com>
Link: https://lore.kernel.org/r/20241009235352.1614323-2-jstultz@google.com
Diffstat (limited to 'kernel/locking/mutex.c')
| -rw-r--r-- | kernel/locking/mutex.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index cbae8c0b89ab..6c94da061ec2 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -575,6 +575,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas struct lockdep_map *nest_lock, unsigned long ip, struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx) { + DEFINE_WAKE_Q(wake_q); struct mutex_waiter waiter; struct ww_mutex *ww; int ret; @@ -625,7 +626,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas */ if (__mutex_trylock(lock)) { if (ww_ctx) - __ww_mutex_check_waiters(lock, ww_ctx); + __ww_mutex_check_waiters(lock, ww_ctx, &wake_q); goto skip_wait; } @@ -645,7 +646,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas * Add in stamp order, waking up waiters that must kill * themselves. */ - ret = __ww_mutex_add_waiter(&waiter, lock, ww_ctx); + ret = __ww_mutex_add_waiter(&waiter, lock, ww_ctx, &wake_q); if (ret) goto err_early_kill; } @@ -681,6 +682,10 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas } raw_spin_unlock(&lock->wait_lock); + /* Make sure we do wakeups before calling schedule */ + wake_up_q(&wake_q); + wake_q_init(&wake_q); + schedule_preempt_disabled(); first = __mutex_waiter_is_first(lock, &waiter); @@ -714,7 +719,7 @@ acquired: */ if (!ww_ctx->is_wait_die && !__mutex_waiter_is_first(lock, &waiter)) - __ww_mutex_check_waiters(lock, ww_ctx); + __ww_mutex_check_waiters(lock, ww_ctx, &wake_q); } __mutex_remove_waiter(lock, &waiter); @@ -730,6 +735,7 @@ skip_wait: ww_mutex_lock_acquired(ww, ww_ctx); raw_spin_unlock(&lock->wait_lock); + wake_up_q(&wake_q); preempt_enable(); return 0; @@ -741,6 +747,7 @@ err_early_kill: raw_spin_unlock(&lock->wait_lock); debug_mutex_free_waiter(&waiter); mutex_release(&lock->dep_map, ip); + wake_up_q(&wake_q); preempt_enable(); return ret; } @@ -951,9 +958,10 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne if (owner & MUTEX_FLAG_HANDOFF) __mutex_handoff(lock, next); + preempt_disable(); raw_spin_unlock(&lock->wait_lock); - wake_up_q(&wake_q); + preempt_enable(); } #ifndef CONFIG_DEBUG_LOCK_ALLOC |