#include "sched.h" /* * stop-task scheduling class. * * The stop task is the highest priority task in the system, it preempts * everything and will be preempted by nothing. * * See kernel/stop_machine.c */ #ifdef CONFIG_SMP static int select_task_rq_stop(struct task_struct *p, int cpu, int sd_flag, int flags) { return task_cpu(p); /* stop tasks as never migrate */ } #endif /* CONFIG_SMP */ static void check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags) { /* we're never preempted */ } static struct task_struct * pick_next_task_stop(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie) { struct task_struct *stop = rq->stop; if (!stop || !task_on_rq_queued(stop)) return NULL; put_prev_task(rq, prev); stop->se.exec_start = rq_clock_task(rq); return stop; } static void enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags) { add_nr_running(rq, 1); } static void dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags) { sub_nr_running(rq, 1); } static void yield_task_stop(struct rq *rq) { BUG(); /* the stop task should never yield, its pointless. */ } static void put_prev_task_stop(struct rq *rq, struct task_struct *prev) { struct task_struct *curr = rq->curr; u64 delta_exec; delta_exec = rq_clock_task(rq) - curr->se.exec_start; if (unlikely((s64)delta_exec < 0)) delta_exec = 0; schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); curr->se.sum_exec_runtime += delta_exec; account_group_exec_runtime(curr, delta_exec); curr->se.exec_start = rq_clock_task(rq); cpuacct_charge(curr, delta_exec); } static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued) { } static void set_curr_task_stop(struct rq *rq) { struct task_struct *stop = rq->stop; stop->se.exec_start = rq_clock_task(rq); } static void switched_to_stop(struct rq *rq, struct task_struct *p) { BUG(); /* its impossible to change to this class */ } static void prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio) { BUG(); /* how!?, what priority? */ } static unsigned int get_rr_interval_stop(struct rq *rq, struct task_struct *task) { return 0; } static void update_curr_stop(struct rq *rq) { } /* * Simple, special scheduling class for the per-CPU stop tasks: */ const struct sched_class stop_sched_class = { .next = &dl_sched_class, .enqueue_task = enqueue_task_stop, .dequeue_task = dequeue_task_stop, .yield_task = yield_task_stop, .check_preempt_curr = check_preempt_curr_stop, .pick_next_task = pick_next_task_stop, .put_prev_task = put_prev_task_stop, #ifdef CONFIG_SMP .select_task_rq = select_task_rq_stop, .set_cpus_allowed = set_cpus_allowed_common, #endif .set_curr_task = set_curr_task_stop, .task_tick = task_tick_stop, .get_rr_interval = get_rr_interval_stop, .prio_changed = prio_changed_stop, .switched_to = switched_to_stop, .update_curr = update_curr_stop, }; t/net/dccp/qpolicy.c?id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>qpolicy.c
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authorThomas Gleixner <tglx@linutronix.de>2017-01-31 09:37:34 +0100
committerThomas Gleixner <tglx@linutronix.de>2017-01-31 21:47:58 +0100
commit0becc0ae5b42828785b589f686725ff5bc3b9b25 (patch)
treebe6d0e1f37c38ed0a7dd5da2d4b1e93f0fb43101 /net/dccp/qpolicy.c
parent24c2503255d35c269b67162c397a1a1c1e02f6ce (diff)
x86/mce: Make timer handling more robust
Erik reported that on a preproduction hardware a CMCI storm triggers the BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is started by the CMCI logic before the MCE CPU hotplug callback starts the timer with add_timer_on(). So the timer is already queued which triggers the BUG. Using add_timer_on() is pretty pointless in this code because the timer is strictlty per CPU, initialized as pinned and all operations which arm the timer happen on the CPU to which the timer belongs. Simplify the whole machinery by using mod_timer() instead of add_timer_on() which avoids the problem because mod_timer() can handle already queued timers. Use __start_timer() everywhere so the earliest armed expiry time is preserved. Reported-by: Erik Veijola <erik.veijola@intel.com> Tested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@alien8.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'net/dccp/qpolicy.c')