diff options
author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-11-21 12:21:53 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-11-21 12:21:53 +0300 |
commit | 05df6ab8eba625a1d97eb67ee06d786b8e460685 (patch) | |
tree | 7fed59b7f49fd8d816475ca6b20c95c7f837ca6f /kernel/sched/core.c | |
parent | 1d926e259d8f8195fdfaeea7951149001894b473 (diff) | |
parent | eb7081409f94a9a8608593d0fb63a1aa3d6f95d8 (diff) | |
download | linux-05df6ab8eba625a1d97eb67ee06d786b8e460685.tar.xz |
Merge 6.1-rc6 into driver-core-next
We need the kernfs changes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/sched/core.c')
-rw-r--r-- | kernel/sched/core.c | 76 |
1 files changed, 47 insertions, 29 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5800b0623ff3..daff72f00385 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4200,6 +4200,40 @@ out: return success; } +static bool __task_needs_rq_lock(struct task_struct *p) +{ + unsigned int state = READ_ONCE(p->__state); + + /* + * Since pi->lock blocks try_to_wake_up(), we don't need rq->lock when + * the task is blocked. Make sure to check @state since ttwu() can drop + * locks at the end, see ttwu_queue_wakelist(). + */ + if (state == TASK_RUNNING || state == TASK_WAKING) + return true; + + /* + * Ensure we load p->on_rq after p->__state, otherwise it would be + * possible to, falsely, observe p->on_rq == 0. + * + * See try_to_wake_up() for a longer comment. + */ + smp_rmb(); + if (p->on_rq) + return true; + +#ifdef CONFIG_SMP + /* + * Ensure the task has finished __schedule() and will not be referenced + * anymore. Again, see try_to_wake_up() for a longer comment. + */ + smp_rmb(); + smp_cond_load_acquire(&p->on_cpu, !VAL); +#endif + + return false; +} + /** * task_call_func - Invoke a function on task in fixed state * @p: Process for which the function is to be invoked, can be @current. @@ -4217,28 +4251,12 @@ out: int task_call_func(struct task_struct *p, task_call_f func, void *arg) { struct rq *rq = NULL; - unsigned int state; struct rq_flags rf; int ret; raw_spin_lock_irqsave(&p->pi_lock, rf.flags); - state = READ_ONCE(p->__state); - - /* - * Ensure we load p->on_rq after p->__state, otherwise it would be - * possible to, falsely, observe p->on_rq == 0. - * - * See try_to_wake_up() for a longer comment. - */ - smp_rmb(); - - /* - * Since pi->lock blocks try_to_wake_up(), we don't need rq->lock when - * the task is blocked. Make sure to check @state since ttwu() can drop - * locks at the end, see ttwu_queue_wakelist(). - */ - if (state == TASK_RUNNING || state == TASK_WAKING || p->on_rq) + if (__task_needs_rq_lock(p)) rq = __task_rq_lock(p, &rf); /* @@ -4823,10 +4841,10 @@ static inline void finish_task(struct task_struct *prev) #ifdef CONFIG_SMP -static void do_balance_callbacks(struct rq *rq, struct callback_head *head) +static void do_balance_callbacks(struct rq *rq, struct balance_callback *head) { void (*func)(struct rq *rq); - struct callback_head *next; + struct balance_callback *next; lockdep_assert_rq_held(rq); @@ -4853,15 +4871,15 @@ static void balance_push(struct rq *rq); * This abuse is tolerated because it places all the unlikely/odd cases behind * a single test, namely: rq->balance_callback == NULL. */ -struct callback_head balance_push_callback = { +struct balance_callback balance_push_callback = { .next = NULL, - .func = (void (*)(struct callback_head *))balance_push, + .func = balance_push, }; -static inline struct callback_head * +static inline struct balance_callback * __splice_balance_callbacks(struct rq *rq, bool split) { - struct callback_head *head = rq->balance_callback; + struct balance_callback *head = rq->balance_callback; if (likely(!head)) return NULL; @@ -4883,7 +4901,7 @@ __splice_balance_callbacks(struct rq *rq, bool split) return head; } -static inline struct callback_head *splice_balance_callbacks(struct rq *rq) +static inline struct balance_callback *splice_balance_callbacks(struct rq *rq) { return __splice_balance_callbacks(rq, true); } @@ -4893,7 +4911,7 @@ static void __balance_callbacks(struct rq *rq) do_balance_callbacks(rq, __splice_balance_callbacks(rq, false)); } -static inline void balance_callbacks(struct rq *rq, struct callback_head *head) +static inline void balance_callbacks(struct rq *rq, struct balance_callback *head) { unsigned long flags; @@ -4910,12 +4928,12 @@ static inline void __balance_callbacks(struct rq *rq) { } -static inline struct callback_head *splice_balance_callbacks(struct rq *rq) +static inline struct balance_callback *splice_balance_callbacks(struct rq *rq) { return NULL; } -static inline void balance_callbacks(struct rq *rq, struct callback_head *head) +static inline void balance_callbacks(struct rq *rq, struct balance_callback *head) { } @@ -6188,7 +6206,7 @@ static void sched_core_balance(struct rq *rq) preempt_enable(); } -static DEFINE_PER_CPU(struct callback_head, core_balance_head); +static DEFINE_PER_CPU(struct balance_callback, core_balance_head); static void queue_core_balance(struct rq *rq) { @@ -7419,7 +7437,7 @@ static int __sched_setscheduler(struct task_struct *p, int oldpolicy = -1, policy = attr->sched_policy; int retval, oldprio, newprio, queued, running; const struct sched_class *prev_class; - struct callback_head *head; + struct balance_callback *head; struct rq_flags rf; int reset_on_fork; int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK; |