diff options
author | Ingo Molnar <mingo@kernel.org> | 2017-11-29 07:11:24 +0100 |
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committer | Ingo Molnar <mingo@kernel.org> | 2017-11-29 07:11:24 +0100 |
commit | 4fc31ba13d052c2933bf91095c063cf9a39effd0 (patch) | |
tree | beabb73c2fe245e6541126732895da62e55bc8ee /kernel/events | |
parent | 0e18dd12064e07519f7cbff4149ca7fff620cbed (diff) | |
parent | b29c6ef7bb1257853c1e31616d84f55e561cf631 (diff) | |
download | linux-stable-4fc31ba13d052c2933bf91095c063cf9a39effd0.tar.gz linux-stable-4fc31ba13d052c2933bf91095c063cf9a39effd0.tar.bz2 linux-stable-4fc31ba13d052c2933bf91095c063cf9a39effd0.zip |
Merge branch 'linus' into perf/urgent, to pick up dependent commits
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r-- | kernel/events/core.c | 492 | ||||
-rw-r--r-- | kernel/events/ring_buffer.c | 2 |
2 files changed, 211 insertions, 283 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index ab5ac84f82e2..6ceb10d87462 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -209,7 +209,7 @@ static int event_function(void *info) struct perf_event_context *task_ctx = cpuctx->task_ctx; int ret = 0; - WARN_ON_ONCE(!irqs_disabled()); + lockdep_assert_irqs_disabled(); perf_ctx_lock(cpuctx, task_ctx); /* @@ -306,7 +306,7 @@ static void event_function_local(struct perf_event *event, event_f func, void *d struct task_struct *task = READ_ONCE(ctx->task); struct perf_event_context *task_ctx = NULL; - WARN_ON_ONCE(!irqs_disabled()); + lockdep_assert_irqs_disabled(); if (task) { if (task == TASK_TOMBSTONE) @@ -582,6 +582,88 @@ static inline u64 perf_event_clock(struct perf_event *event) return event->clock(); } +/* + * State based event timekeeping... + * + * The basic idea is to use event->state to determine which (if any) time + * fields to increment with the current delta. This means we only need to + * update timestamps when we change state or when they are explicitly requested + * (read). + * + * Event groups make things a little more complicated, but not terribly so. The + * rules for a group are that if the group leader is OFF the entire group is + * OFF, irrespecive of what the group member states are. This results in + * __perf_effective_state(). + * + * A futher ramification is that when a group leader flips between OFF and + * !OFF, we need to update all group member times. + * + * + * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we + * need to make sure the relevant context time is updated before we try and + * update our timestamps. + */ + +static __always_inline enum perf_event_state +__perf_effective_state(struct perf_event *event) +{ + struct perf_event *leader = event->group_leader; + + if (leader->state <= PERF_EVENT_STATE_OFF) + return leader->state; + + return event->state; +} + +static __always_inline void +__perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running) +{ + enum perf_event_state state = __perf_effective_state(event); + u64 delta = now - event->tstamp; + + *enabled = event->total_time_enabled; + if (state >= PERF_EVENT_STATE_INACTIVE) + *enabled += delta; + + *running = event->total_time_running; + if (state >= PERF_EVENT_STATE_ACTIVE) + *running += delta; +} + +static void perf_event_update_time(struct perf_event *event) +{ + u64 now = perf_event_time(event); + + __perf_update_times(event, now, &event->total_time_enabled, + &event->total_time_running); + event->tstamp = now; +} + +static void perf_event_update_sibling_time(struct perf_event *leader) +{ + struct perf_event *sibling; + + list_for_each_entry(sibling, &leader->sibling_list, group_entry) + perf_event_update_time(sibling); +} + +static void +perf_event_set_state(struct perf_event *event, enum perf_event_state state) +{ + if (event->state == state) + return; + + perf_event_update_time(event); + /* + * If a group leader gets enabled/disabled all its siblings + * are affected too. + */ + if ((event->state < 0) ^ (state < 0)) + perf_event_update_sibling_time(event); + + WRITE_ONCE(event->state, state); +} + #ifdef CONFIG_CGROUP_PERF static inline bool @@ -841,40 +923,6 @@ perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) event->shadow_ctx_time = now - t->timestamp; } -static inline void -perf_cgroup_defer_enabled(struct perf_event *event) -{ - /* - * when the current task's perf cgroup does not match - * the event's, we need to remember to call the - * perf_mark_enable() function the first time a task with - * a matching perf cgroup is scheduled in. - */ - if (is_cgroup_event(event) && !perf_cgroup_match(event)) - event->cgrp_defer_enabled = 1; -} - -static inline void -perf_cgroup_mark_enabled(struct perf_event *event, - struct perf_event_context *ctx) -{ - struct perf_event *sub; - u64 tstamp = perf_event_time(event); - - if (!event->cgrp_defer_enabled) - return; - - event->cgrp_defer_enabled = 0; - - event->tstamp_enabled = tstamp - event->total_time_enabled; - list_for_each_entry(sub, &event->sibling_list, group_entry) { - if (sub->state >= PERF_EVENT_STATE_INACTIVE) { - sub->tstamp_enabled = tstamp - sub->total_time_enabled; - sub->cgrp_defer_enabled = 0; - } - } -} - /* * Update cpuctx->cgrp so that it is set when first cgroup event is added and * cleared when last cgroup event is removed. @@ -975,17 +1023,6 @@ static inline u64 perf_cgroup_event_time(struct perf_event *event) } static inline void -perf_cgroup_defer_enabled(struct perf_event *event) -{ -} - -static inline void -perf_cgroup_mark_enabled(struct perf_event *event, - struct perf_event_context *ctx) -{ -} - -static inline void list_update_cgroup_event(struct perf_event *event, struct perf_event_context *ctx, bool add) { @@ -1006,7 +1043,7 @@ static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) struct perf_cpu_context *cpuctx; int rotations = 0; - WARN_ON(!irqs_disabled()); + lockdep_assert_irqs_disabled(); cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); rotations = perf_rotate_context(cpuctx); @@ -1093,7 +1130,7 @@ static void perf_event_ctx_activate(struct perf_event_context *ctx) { struct list_head *head = this_cpu_ptr(&active_ctx_list); - WARN_ON(!irqs_disabled()); + lockdep_assert_irqs_disabled(); WARN_ON(!list_empty(&ctx->active_ctx_list)); @@ -1102,7 +1139,7 @@ static void perf_event_ctx_activate(struct perf_event_context *ctx) static void perf_event_ctx_deactivate(struct perf_event_context *ctx) { - WARN_ON(!irqs_disabled()); + lockdep_assert_irqs_disabled(); WARN_ON(list_empty(&ctx->active_ctx_list)); @@ -1202,7 +1239,7 @@ perf_event_ctx_lock_nested(struct perf_event *event, int nesting) again: rcu_read_lock(); - ctx = ACCESS_ONCE(event->ctx); + ctx = READ_ONCE(event->ctx); if (!atomic_inc_not_zero(&ctx->refcount)) { rcu_read_unlock(); goto again; @@ -1398,60 +1435,6 @@ static u64 perf_event_time(struct perf_event *event) return ctx ? ctx->time : 0; } -/* - * Update the total_time_enabled and total_time_running fields for a event. - */ -static void update_event_times(struct perf_event *event) -{ - struct perf_event_context *ctx = event->ctx; - u64 run_end; - - lockdep_assert_held(&ctx->lock); - - if (event->state < PERF_EVENT_STATE_INACTIVE || - event->group_leader->state < PERF_EVENT_STATE_INACTIVE) - return; - - /* - * in cgroup mode, time_enabled represents - * the time the event was enabled AND active - * tasks were in the monitored cgroup. This is - * independent of the activity of the context as - * there may be a mix of cgroup and non-cgroup events. - * - * That is why we treat cgroup events differently - * here. - */ - if (is_cgroup_event(event)) - run_end = perf_cgroup_event_time(event); - else if (ctx->is_active) - run_end = ctx->time; - else - run_end = event->tstamp_stopped; - - event->total_time_enabled = run_end - event->tstamp_enabled; - - if (event->state == PERF_EVENT_STATE_INACTIVE) - run_end = event->tstamp_stopped; - else - run_end = perf_event_time(event); - - event->total_time_running = run_end - event->tstamp_running; - -} - -/* - * Update total_time_enabled and total_time_running for all events in a group. - */ -static void update_group_times(struct perf_event *leader) -{ - struct perf_event *event; - - update_event_times(leader); - list_for_each_entry(event, &leader->sibling_list, group_entry) - update_event_times(event); -} - static enum event_type_t get_event_type(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; @@ -1494,6 +1477,8 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx) WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); event->attach_state |= PERF_ATTACH_CONTEXT; + event->tstamp = perf_event_time(event); + /* * If we're a stand alone event or group leader, we go to the context * list, group events are kept attached to the group so that @@ -1701,8 +1686,6 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx) if (event->group_leader == event) list_del_init(&event->group_entry); - update_group_times(event); - /* * If event was in error state, then keep it * that way, otherwise bogus counts will be @@ -1711,7 +1694,7 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx) * of the event */ if (event->state > PERF_EVENT_STATE_OFF) - event->state = PERF_EVENT_STATE_OFF; + perf_event_set_state(event, PERF_EVENT_STATE_OFF); ctx->generation++; } @@ -1810,38 +1793,24 @@ event_sched_out(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { - u64 tstamp = perf_event_time(event); - u64 delta; + enum perf_event_state state = PERF_EVENT_STATE_INACTIVE; WARN_ON_ONCE(event->ctx != ctx); lockdep_assert_held(&ctx->lock); - /* - * An event which could not be activated because of - * filter mismatch still needs to have its timings - * maintained, otherwise bogus information is return - * via read() for time_enabled, time_running: - */ - if (event->state == PERF_EVENT_STATE_INACTIVE && - !event_filter_match(event)) { - delta = tstamp - event->tstamp_stopped; - event->tstamp_running += delta; - event->tstamp_stopped = tstamp; - } - if (event->state != PERF_EVENT_STATE_ACTIVE) return; perf_pmu_disable(event->pmu); - event->tstamp_stopped = tstamp; event->pmu->del(event, 0); event->oncpu = -1; - event->state = PERF_EVENT_STATE_INACTIVE; + if (event->pending_disable) { event->pending_disable = 0; - event->state = PERF_EVENT_STATE_OFF; + state = PERF_EVENT_STATE_OFF; } + perf_event_set_state(event, state); if (!is_software_event(event)) cpuctx->active_oncpu--; @@ -1861,7 +1830,9 @@ group_sched_out(struct perf_event *group_event, struct perf_event_context *ctx) { struct perf_event *event; - int state = group_event->state; + + if (group_event->state != PERF_EVENT_STATE_ACTIVE) + return; perf_pmu_disable(ctx->pmu); @@ -1875,7 +1846,7 @@ group_sched_out(struct perf_event *group_event, perf_pmu_enable(ctx->pmu); - if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) + if (group_event->attr.exclusive) cpuctx->exclusive = 0; } @@ -1895,6 +1866,11 @@ __perf_remove_from_context(struct perf_event *event, { unsigned long flags = (unsigned long)info; + if (ctx->is_active & EVENT_TIME) { + update_context_time(ctx); + update_cgrp_time_from_cpuctx(cpuctx); + } + event_sched_out(event, cpuctx, ctx); if (flags & DETACH_GROUP) perf_group_detach(event); @@ -1957,14 +1933,17 @@ static void __perf_event_disable(struct perf_event *event, if (event->state < PERF_EVENT_STATE_INACTIVE) return; - update_context_time(ctx); - update_cgrp_time_from_event(event); - update_group_times(event); + if (ctx->is_active & EVENT_TIME) { + update_context_time(ctx); + update_cgrp_time_from_event(event); + } + if (event == event->group_leader) group_sched_out(event, cpuctx, ctx); else event_sched_out(event, cpuctx, ctx); - event->state = PERF_EVENT_STATE_OFF; + + perf_event_set_state(event, PERF_EVENT_STATE_OFF); } /* @@ -2021,8 +2000,7 @@ void perf_event_disable_inatomic(struct perf_event *event) } static void perf_set_shadow_time(struct perf_event *event, - struct perf_event_context *ctx, - u64 tstamp) + struct perf_event_context *ctx) { /* * use the correct time source for the time snapshot @@ -2050,9 +2028,9 @@ static void perf_set_shadow_time(struct perf_event *event, * is cleaner and simpler to understand. */ if (is_cgroup_event(event)) - perf_cgroup_set_shadow_time(event, tstamp); + perf_cgroup_set_shadow_time(event, event->tstamp); else - event->shadow_ctx_time = tstamp - ctx->timestamp; + event->shadow_ctx_time = event->tstamp - ctx->timestamp; } #define MAX_INTERRUPTS (~0ULL) @@ -2065,7 +2043,6 @@ event_sched_in(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { - u64 tstamp = perf_event_time(event); int ret = 0; lockdep_assert_held(&ctx->lock); @@ -2075,11 +2052,12 @@ event_sched_in(struct perf_event *event, WRITE_ONCE(event->oncpu, smp_processor_id()); /* - * Order event::oncpu write to happen before the ACTIVE state - * is visible. + * Order event::oncpu write to happen before the ACTIVE state is + * visible. This allows perf_event_{stop,read}() to observe the correct + * ->oncpu if it sees ACTIVE. */ smp_wmb(); - WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE); + perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE); /* * Unthrottle events, since we scheduled we might have missed several @@ -2091,26 +2069,19 @@ event_sched_in(struct perf_event *event, event->hw.interrupts = 0; } - /* - * The new state must be visible before we turn it on in the hardware: - */ - smp_wmb(); - perf_pmu_disable(event->pmu); - perf_set_shadow_time(event, ctx, tstamp); + perf_set_shadow_time(event, ctx); perf_log_itrace_start(event); if (event->pmu->add(event, PERF_EF_START)) { - event->state = PERF_EVENT_STATE_INACTIVE; + perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); event->oncpu = -1; ret = -EAGAIN; goto out; } - event->tstamp_running += tstamp - event->tstamp_stopped; - if (!is_software_event(event)) cpuctx->active_oncpu++; if (!ctx->nr_active++) @@ -2134,8 +2105,6 @@ group_sched_in(struct perf_event *group_event, { struct perf_event *event, *partial_group = NULL; struct pmu *pmu = ctx->pmu; - u64 now = ctx->time; - bool simulate = false; if (group_event->state == PERF_EVENT_STATE_OFF) return 0; @@ -2165,27 +2134,13 @@ group_error: /* * Groups can be scheduled in as one unit only, so undo any * partial group before returning: - * The events up to the failed event are scheduled out normally, - * tstamp_stopped will be updated. - * - * The failed events and the remaining siblings need to have - * their timings updated as if they had gone thru event_sched_in() - * and event_sched_out(). This is required to get consistent timings - * across the group. This also takes care of the case where the group - * could never be scheduled by ensuring tstamp_stopped is set to mark - * the time the event was actually stopped, such that time delta - * calculation in update_event_times() is correct. + * The events up to the failed event are scheduled out normally. */ list_for_each_entry(event, &group_event->sibling_list, group_entry) { if (event == partial_group) - simulate = true; + break; - if (simulate) { - event->tstamp_running += now - event->tstamp_stopped; - event->tstamp_stopped = now; - } else { - event_sched_out(event, cpuctx, ctx); - } + event_sched_out(event, cpuctx, ctx); } event_sched_out(group_event, cpuctx, ctx); @@ -2227,46 +2182,11 @@ static int group_can_go_on(struct perf_event *event, return can_add_hw; } -/* - * Complement to update_event_times(). This computes the tstamp_* values to - * continue 'enabled' state from @now, and effectively discards the time - * between the prior tstamp_stopped and now (as we were in the OFF state, or - * just switched (context) time base). - * - * This further assumes '@event->state == INACTIVE' (we just came from OFF) and - * cannot have been scheduled in yet. And going into INACTIVE state means - * '@event->tstamp_stopped = @now'. - * - * Thus given the rules of update_event_times(): - * - * total_time_enabled = tstamp_stopped - tstamp_enabled - * total_time_running = tstamp_stopped - tstamp_running - * - * We can insert 'tstamp_stopped == now' and reverse them to compute new - * tstamp_* values. - */ -static void __perf_event_enable_time(struct perf_event *event, u64 now) -{ - WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE); - - event->tstamp_stopped = now; - event->tstamp_enabled = now - event->total_time_enabled; - event->tstamp_running = now - event->total_time_running; -} - static void add_event_to_ctx(struct perf_event *event, struct perf_event_context *ctx) { - u64 tstamp = perf_event_time(event); - list_add_event(event, ctx); perf_group_attach(event); - /* - * We can be called with event->state == STATE_OFF when we create with - * .disabled = 1. In that case the IOC_ENABLE will call this function. - */ - if (event->state == PERF_EVENT_STATE_INACTIVE) - __perf_event_enable_time(event, tstamp); } static void ctx_sched_out(struct perf_event_context *ctx, @@ -2498,28 +2418,6 @@ again: } /* - * Put a event into inactive state and update time fields. - * Enabling the leader of a group effectively enables all - * the group members that aren't explicitly disabled, so we - * have to update their ->tstamp_enabled also. - * Note: this works for group members as well as group leaders - * since the non-leader members' sibling_lists will be empty. - */ -static void __perf_event_mark_enabled(struct perf_event *event) -{ - struct perf_event *sub; - u64 tstamp = perf_event_time(event); - - event->state = PERF_EVENT_STATE_INACTIVE; - __perf_event_enable_time(event, tstamp); - list_for_each_entry(sub, &event->sibling_list, group_entry) { - /* XXX should not be > INACTIVE if event isn't */ - if (sub->state >= PERF_EVENT_STATE_INACTIVE) - __perf_event_enable_time(sub, tstamp); - } -} - -/* * Cross CPU call to enable a performance event */ static void __perf_event_enable(struct perf_event *event, @@ -2537,14 +2435,12 @@ static void __perf_event_enable(struct perf_event *event, if (ctx->is_active) ctx_sched_out(ctx, cpuctx, EVENT_TIME); - __perf_event_mark_enabled(event); + perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); if (!ctx->is_active) return; if (!event_filter_match(event)) { - if (is_cgroup_event(event)) - perf_cgroup_defer_enabled(event); ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); return; } @@ -2864,18 +2760,10 @@ static void __perf_event_sync_stat(struct perf_event *event, * we know the event must be on the current CPU, therefore we * don't need to use it. */ - switch (event->state) { - case PERF_EVENT_STATE_ACTIVE: + if (event->state == PERF_EVENT_STATE_ACTIVE) event->pmu->read(event); - /* fall-through */ - - case PERF_EVENT_STATE_INACTIVE: - update_event_times(event); - break; - default: - break; - } + perf_event_update_time(event); /* * In order to keep per-task stats reliable we need to flip the event @@ -3112,10 +3000,6 @@ ctx_pinned_sched_in(struct perf_event_context *ctx, if (!event_filter_match(event)) continue; - /* may need to reset tstamp_enabled */ - if (is_cgroup_event(event)) - perf_cgroup_mark_enabled(event, ctx); - if (group_can_go_on(event, cpuctx, 1)) group_sched_in(event, cpuctx, ctx); @@ -3123,10 +3007,8 @@ ctx_pinned_sched_in(struct perf_event_context *ctx, * If this pinned group hasn't been scheduled, * put it in error state. */ - if (event->state == PERF_EVENT_STATE_INACTIVE) { - update_group_times(event); - event->state = PERF_EVENT_STATE_ERROR; - } + if (event->state == PERF_EVENT_STATE_INACTIVE) + perf_event_set_state(event, PERF_EVENT_STATE_ERROR); } } @@ -3148,10 +3030,6 @@ ctx_flexible_sched_in(struct perf_event_context *ctx, if (!event_filter_match(event)) continue; - /* may need to reset tstamp_enabled */ - if (is_cgroup_event(event)) - perf_cgroup_mark_enabled(event, ctx); - if (group_can_go_on(event, cpuctx, can_add_hw)) { if (group_sched_in(event, cpuctx, ctx)) can_add_hw = 0; @@ -3523,7 +3401,7 @@ void perf_event_task_tick(void) struct perf_event_context *ctx, *tmp; int throttled; - WARN_ON(!irqs_disabled()); + lockdep_assert_irqs_disabled(); __this_cpu_inc(perf_throttled_seq); throttled = __this_cpu_xchg(perf_throttled_count, 0); @@ -3543,7 +3421,7 @@ static int event_enable_on_exec(struct perf_event *event, if (event->state >= PERF_EVENT_STATE_INACTIVE) return 0; - __perf_event_mark_enabled(event); + perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); return 1; } @@ -3637,12 +3515,15 @@ static void __perf_event_read(void *info) return; raw_spin_lock(&ctx->lock); - if (ctx->is_active) { + if (ctx->is_active & EVENT_TIME) { update_context_time(ctx); update_cgrp_time_from_event(event); } - update_event_times(event); + perf_event_update_time(event); + if (data->group) + perf_event_update_sibling_time(event); + if (event->state != PERF_EVENT_STATE_ACTIVE) goto unlock; @@ -3657,7 +3538,6 @@ static void __perf_event_read(void *info) pmu->read(event); list_for_each_entry(sub, &event->sibling_list, group_entry) { - update_event_times(sub); if (sub->state == PERF_EVENT_STATE_ACTIVE) { /* * Use sibling's PMU rather than @event's since @@ -3686,7 +3566,8 @@ static inline u64 perf_event_count(struct perf_event *event) * will not be local and we cannot read them atomically * - must not have a pmu::count method */ -int perf_event_read_local(struct perf_event *event, u64 *value) +int perf_event_read_local(struct perf_event *event, u64 *value, + u64 *enabled, u64 *running) { unsigned long flags; int ret = 0; @@ -3720,6 +3601,7 @@ int perf_event_read_local(struct perf_event *event, u64 *value) goto out; } + /* * If the event is currently on this CPU, its either a per-task event, * or local to this CPU. Furthermore it means its ACTIVE (otherwise @@ -3729,6 +3611,16 @@ int perf_event_read_local(struct perf_event *event, u64 *value) event->pmu->read(event); *value = local64_read(&event->count); + if (enabled || running) { + u64 now = event->shadow_ctx_time + perf_clock(); + u64 __enabled, __running; + + __perf_update_times(event, now, &__enabled, &__running); + if (enabled) + *enabled = __enabled; + if (running) + *running = __running; + } out: local_irq_restore(flags); @@ -3737,23 +3629,35 @@ out: static int perf_event_read(struct perf_event *event, bool group) { + enum perf_event_state state = READ_ONCE(event->state); int event_cpu, ret = 0; /* * If event is enabled and currently active on a CPU, update the * value in the event structure: */ - if (event->state == PERF_EVENT_STATE_ACTIVE) { - struct perf_read_data data = { - .event = event, - .group = group, - .ret = 0, - }; +again: + if (state == PERF_EVENT_STATE_ACTIVE) { + struct perf_read_data data; + + /* + * Orders the ->state and ->oncpu loads such that if we see + * ACTIVE we must also see the right ->oncpu. + * + * Matches the smp_wmb() from event_sched_in(). + */ + smp_rmb(); event_cpu = READ_ONCE(event->oncpu); if ((unsigned)event_cpu >= nr_cpu_ids) return 0; + data = (struct perf_read_data){ + .event = event, + .group = group, + .ret = 0, + }; + preempt_disable(); event_cpu = __perf_event_read_cpu(event, event_cpu); @@ -3770,24 +3674,30 @@ static int perf_event_read(struct perf_event *event, bool group) (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); preempt_enable(); ret = data.ret; - } else if (event->state == PERF_EVENT_STATE_INACTIVE) { + + } else if (state == PERF_EVENT_STATE_INACTIVE) { struct perf_event_context *ctx = event->ctx; unsigned long flags; raw_spin_lock_irqsave(&ctx->lock, flags); + state = event->state; + if (state != PERF_EVENT_STATE_INACTIVE) { + raw_spin_unlock_irqrestore(&ctx->lock, flags); + goto again; + } + /* - * may read while context is not active - * (e.g., thread is blocked), in that case - * we cannot update context time + * May read while context is not active (e.g., thread is + * blocked), in that case we cannot update context time */ - if (ctx->is_active) { + if (ctx->is_active & EVENT_TIME) { update_context_time(ctx); update_cgrp_time_from_event(event); } + + perf_event_update_time(event); if (group) - update_group_times(event); - else - update_event_times(event); + perf_event_update_sibling_time(event); raw_spin_unlock_irqrestore(&ctx->lock, flags); } @@ -4233,7 +4143,7 @@ static void perf_remove_from_owner(struct perf_event *event) * indeed free this event, otherwise we need to serialize on * owner->perf_event_mutex. */ - owner = lockless_dereference(event->owner); + owner = READ_ONCE(event->owner); if (owner) { /* * Since delayed_put_task_struct() also drops the last @@ -4330,7 +4240,7 @@ again: * Cannot change, child events are not migrated, see the * comment with perf_event_ctx_lock_nested(). */ - ctx = lockless_dereference(child->ctx); + ctx = READ_ONCE(child->ctx); /* * Since child_mutex nests inside ctx::mutex, we must jump * through hoops. We start by grabbing a reference on the ctx. @@ -4390,7 +4300,7 @@ static int perf_release(struct inode *inode, struct file *file) return 0; } -u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) +static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) { struct perf_event *child; u64 total = 0; @@ -4418,6 +4328,18 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) return total; } + +u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) +{ + struct perf_event_context *ctx; + u64 count; + + ctx = perf_event_ctx_lock(event); + count = __perf_event_read_value(event, enabled, running); + perf_event_ctx_unlock(event, ctx); + + return count; +} EXPORT_SYMBOL_GPL(perf_event_read_value); static int __perf_read_group_add(struct perf_event *leader, @@ -4433,6 +4355,8 @@ static int __perf_read_group_add(struct perf_event *leader, if (ret) return ret; + raw_spin_lock_irqsave(&ctx->lock, flags); + /* * Since we co-schedule groups, {enabled,running} times of siblings * will be identical to those of the leader, so we only publish one @@ -4455,8 +4379,6 @@ static int __perf_read_group_add(struct perf_event *leader, if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); - raw_spin_lock_irqsave(&ctx->lock, flags); - list_for_each_entry(sub, &leader->sibling_list, group_entry) { values[n++] += perf_event_count(sub); if (read_format & PERF_FORMAT_ID) @@ -4520,7 +4442,7 @@ static int perf_read_one(struct perf_event *event, u64 values[4]; int n = 0; - values[n++] = perf_event_read_value(event, &enabled, &running); + values[n++] = __perf_event_read_value(event, &enabled, &running); if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) values[n++] = enabled; if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) @@ -4899,8 +4821,7 @@ static void calc_timer_values(struct perf_event *event, *now = perf_clock(); ctx_time = event->shadow_ctx_time + *now; - *enabled = ctx_time - event->tstamp_enabled; - *running = ctx_time - event->tstamp_running; + __perf_update_times(event, ctx_time, enabled, running); } static void perf_event_init_userpage(struct perf_event *event) @@ -5304,8 +5225,8 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) if (!rb) goto aux_unlock; - aux_offset = ACCESS_ONCE(rb->user_page->aux_offset); - aux_size = ACCESS_ONCE(rb->user_page->aux_size); + aux_offset = READ_ONCE(rb->user_page->aux_offset); + aux_size = READ_ONCE(rb->user_page->aux_size); if (aux_offset < perf_data_size(rb) + PAGE_SIZE) goto aux_unlock; @@ -8075,6 +7996,7 @@ static void bpf_overflow_handler(struct perf_event *event, struct bpf_perf_event_data_kern ctx = { .data = data, .regs = regs, + .event = event, }; int ret = 0; @@ -9405,6 +9327,11 @@ static void account_event(struct perf_event *event) inc = true; if (inc) { + /* + * We need the mutex here because static_branch_enable() + * must complete *before* the perf_sched_count increment + * becomes visible. + */ if (atomic_inc_not_zero(&perf_sched_count)) goto enabled; @@ -10530,7 +10457,7 @@ perf_event_exit_event(struct perf_event *child_event, if (parent_event) perf_group_detach(child_event); list_del_event(child_event, child_ctx); - child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */ + perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */ raw_spin_unlock_irq(&child_ctx->lock); /* @@ -10768,7 +10695,7 @@ inherit_event(struct perf_event *parent_event, struct perf_event *group_leader, struct perf_event_context *child_ctx) { - enum perf_event_active_state parent_state = parent_event->state; + enum perf_event_state parent_state = parent_event->state; struct perf_event *child_event; unsigned long flags; @@ -11104,6 +11031,7 @@ static void __perf_event_exit_context(void *__info) struct perf_event *event; raw_spin_lock(&ctx->lock); + ctx_sched_out(ctx, cpuctx, EVENT_TIME); list_for_each_entry(event, &ctx->event_list, event_entry) __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); raw_spin_unlock(&ctx->lock); diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index f684d8e5fa2b..f3e37971c842 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -381,7 +381,7 @@ void *perf_aux_output_begin(struct perf_output_handle *handle, * (B) <-> (C) ordering is still observed by the pmu driver. */ if (!rb->aux_overwrite) { - aux_tail = ACCESS_ONCE(rb->user_page->aux_tail); + aux_tail = READ_ONCE(rb->user_page->aux_tail); handle->wakeup = rb->aux_wakeup + rb->aux_watermark; if (aux_head - aux_tail < perf_aux_size(rb)) handle->size = CIRC_SPACE(aux_head, aux_tail, perf_aux_size(rb)); |