Ingo, what about the following patch instead?
maybe task_is_current() would be a better name though. Steven, I guess, there is some analogue of UNLOCKED_CTXSW on -rt (to reduce contention for rq->lock). So there can be a race schedule() vs. rt_mutex_setprio() or sched_setscheduler() for some paths that might explain crashes you have been observing? I haven't analyzed this case for -rt, so I'm just throwing in the idea in case it can be useful. --------------------------------------------------- From: Dmitry Adamushko <[EMAIL PROTECTED]> sched: introduce task_current() Some services (e.g. sched_setscheduler(), rt_mutex_setprio() and sched_move_task()) must handle a given task differently in case it's the 'rq->curr' task on its run-queue. The task_running() interface is not suitable for determining such tasks for platforms with one of the following options: #define __ARCH_WANT_UNLOCKED_CTXSW #define __ARCH_WANT_INTERRUPTS_ON_CTXSW Due to the fact that it makes use of 'p->oncpu == 1' as a criterion but such a task is not necessarily 'rq->curr'. The detailed explanation is available here: https://lists.linux-foundation.org/pipermail/containers/2007-December/009262.html Signed-off-by: Dmitry Adamushko <[EMAIL PROTECTED]> --- diff --git a/kernel/sched.c b/kernel/sched.c index dc6fb24..15d088b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -619,10 +619,15 @@ EXPORT_SYMBOL_GPL(cpu_clock); # define finish_arch_switch(prev) do { } while (0) #endif +static inline int task_current(struct rq *rq, struct task_struct *p) +{ + return rq->curr == p; +} + #ifndef __ARCH_WANT_UNLOCKED_CTXSW static inline int task_running(struct rq *rq, struct task_struct *p) { - return rq->curr == p; + return task_current(rq, p); } static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) @@ -651,7 +656,7 @@ static inline int task_running(struct rq *rq, struct task_struct *p) #ifdef CONFIG_SMP return p->oncpu; #else - return rq->curr == p; + return task_current(rq, p); #endif } @@ -3340,7 +3345,7 @@ unsigned long long task_sched_runtime(struct task_struct *p) rq = task_rq_lock(p, &flags); ns = p->se.sum_exec_runtime; - if (rq->curr == p) { + if (task_current(rq, p)) { update_rq_clock(rq); delta_exec = rq->clock - p->se.exec_start; if ((s64)delta_exec > 0) @@ -4033,7 +4038,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio) oldprio = p->prio; on_rq = p->se.on_rq; - running = task_running(rq, p); + running = task_current(rq, p); if (on_rq) { dequeue_task(rq, p, 0); if (running) @@ -4334,7 +4339,7 @@ recheck: } update_rq_clock(rq); on_rq = p->se.on_rq; - running = task_running(rq, p); + running = task_current(rq, p); if (on_rq) { deactivate_task(rq, p, 0); if (running) @@ -7360,7 +7365,7 @@ void sched_move_task(struct task_struct *tsk) update_rq_clock(rq); - running = task_running(rq, tsk); + running = task_current(rq, tsk); on_rq = tsk->se.on_rq; if (on_rq) { --- _______________________________________________ Containers mailing list [EMAIL PROTECTED] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list Devel@openvz.org https://openvz.org/mailman/listinfo/devel
