On Wed, May 13, 2015 at 07:09:40PM -0400, Sasha Levin wrote: > On 05/13/2015 09:43 AM, Peter Zijlstra wrote:
> > So I suppose the below (compile tested) patch should fix things, but > > seeing how I've been up since 4am I might just have missed something > > obvious :-) > > I know exactly how you feel... How about I add a raw_spin_lock_init() for the new lock I added ;-) This one seems to boot and do simple perf things with lockdep enabled. --- include/linux/perf_event.h | 4 ++++ kernel/events/core.c | 29 ++++++++++++++++------------- kernel/sched/core.c | 12 ------------ kernel/sched/fair.c | 17 +++++++++++++---- kernel/sched/rt.c | 8 +++++++- kernel/sched/sched.h | 5 ++--- 6 files changed, 42 insertions(+), 33 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index e86f85abeda7..1f5607b220e4 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -566,8 +566,12 @@ struct perf_cpu_context { struct perf_event_context *task_ctx; int active_oncpu; int exclusive; + + raw_spinlock_t hrtimer_lock; struct hrtimer hrtimer; ktime_t hrtimer_interval; + unsigned int hrtimer_active; + struct pmu *unique_pmu; struct perf_cgroup *cgrp; }; diff --git a/kernel/events/core.c b/kernel/events/core.c index 84231a146dd5..1c6c2826af1e 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -752,24 +752,21 @@ perf_cgroup_mark_enabled(struct perf_event *event, static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) { struct perf_cpu_context *cpuctx; - enum hrtimer_restart ret = HRTIMER_NORESTART; int rotations = 0; WARN_ON(!irqs_disabled()); cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); - rotations = perf_rotate_context(cpuctx); - /* - * arm timer if needed - */ - if (rotations) { + raw_spin_lock(&cpuctx->hrtimer_lock); + if (rotations) hrtimer_forward_now(hr, cpuctx->hrtimer_interval); - ret = HRTIMER_RESTART; - } + else + cpuctx->hrtimer_active = 0; + raw_spin_unlock(&cpuctx->hrtimer_lock); - return ret; + return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; } static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) @@ -792,7 +789,8 @@ static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); - hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED); + raw_spin_lock_init(&cpuctx->hrtimer_lock); + hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); timer->function = perf_mux_hrtimer_handler; } @@ -800,15 +798,20 @@ static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) { struct hrtimer *timer = &cpuctx->hrtimer; struct pmu *pmu = cpuctx->ctx.pmu; + unsigned long flags; /* not for SW PMU */ if (pmu->task_ctx_nr == perf_sw_context) return 0; - if (hrtimer_is_queued(timer)) - return 0; + raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); + if (!cpuctx->hrtimer_active) { + cpuctx->hrtimer_active = 1; + hrtimer_forward_now(timer, cpuctx->hrtimer_interval); + hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); + } + raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); - hrtimer_start(timer, cpuctx->hrtimer_interval, HRTIMER_MODE_REL_PINNED); return 0; } diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 613b61e381ca..bd9182aa74c0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -90,18 +90,6 @@ #define CREATE_TRACE_POINTS #include <trace/events/sched.h> -void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) -{ - /* - * Do not forward the expiration time of active timers; - * we do not want to loose an overrun. - */ - if (!hrtimer_active(period_timer)) - hrtimer_forward_now(period_timer, period); - - hrtimer_start_expires(period_timer, HRTIMER_MODE_ABS_PINNED); -} - DEFINE_MUTEX(sched_domains_mutex); DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8c1510abeefa..2c08783ee95c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3883,8 +3883,9 @@ static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b) if (runtime_refresh_within(cfs_b, min_left)) return; - start_bandwidth_timer(&cfs_b->slack_timer, - ns_to_ktime(cfs_bandwidth_slack_period)); + hrtimer_start(&cfs_b->slack_timer, + ns_to_ktime(cfs_bandwidth_slack_period), + HRTIMER_MODE_REL); } /* we know any runtime found here is valid as update_curr() precedes return */ @@ -4025,6 +4026,8 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) idle = do_sched_cfs_period_timer(cfs_b, overrun); } + if (idle) + cfs_b->period_active = 0; raw_spin_unlock(&cfs_b->lock); return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; @@ -4038,7 +4041,7 @@ void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) cfs_b->period = ns_to_ktime(default_cfs_period()); INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq); - hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); cfs_b->period_timer.function = sched_cfs_period_timer; hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); cfs_b->slack_timer.function = sched_cfs_slack_timer; @@ -4052,7 +4055,13 @@ static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b) { - start_bandwidth_timer(&cfs_b->period_timer, cfs_b->period); + lockdep_assert_held(&cfs_b->lock); + + if (!cfs_b->period_active) { + cfs_b->period_active = 1; + hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period); + hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED); + } } static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 8781a38a636e..7d7093c51f8d 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -31,6 +31,8 @@ static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer) idle = do_sched_rt_period_timer(rt_b, overrun); raw_spin_lock(&rt_b->rt_runtime_lock); } + if (idle) + rt_b->rt_period_active = 0; raw_spin_unlock(&rt_b->rt_runtime_lock); return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; @@ -54,7 +56,11 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b) return; raw_spin_lock(&rt_b->rt_runtime_lock); - start_bandwidth_timer(&rt_b->rt_period_timer, rt_b->rt_period); + if (!rt_b->rt_period_active) { + rt_b->rt_period_active = 1; + hrtimer_forward_now(&rt_b->rt_period_timer, rt_b->rt_period); + hrtimer_start_expires(&rt_b->rt_period_timer, HRTIMER_MODE_ABS_PINNED); + } raw_spin_unlock(&rt_b->rt_runtime_lock); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 460f98648afd..f10a445910c9 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -137,6 +137,7 @@ struct rt_bandwidth { ktime_t rt_period; u64 rt_runtime; struct hrtimer rt_period_timer; + unsigned int rt_period_active; }; void __dl_clear_params(struct task_struct *p); @@ -221,7 +222,7 @@ struct cfs_bandwidth { s64 hierarchical_quota; u64 runtime_expires; - int idle; + int idle, period_active; struct hrtimer period_timer, slack_timer; struct list_head throttled_cfs_rq; @@ -1410,8 +1411,6 @@ static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { } static inline void sched_avg_update(struct rq *rq) { } #endif -extern void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period); - /* * __task_rq_lock - lock the rq @p resides on. */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/