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author | Ingo Molnar <mingo@elte.hu> | 2010-05-20 12:38:55 (GMT) |
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committer | Ingo Molnar <mingo@elte.hu> | 2010-05-20 12:38:55 (GMT) |
commit | dfacc4d6c98b89609250269f518c1f54c30454ef (patch) | |
tree | e7effbee7bdc85d18f7b26ab9cb5c9f700d1481a /kernel/perf_event.c | |
parent | f869097e884d8cb65b2bb7831ca57b7dffb66fdd (diff) | |
parent | 85cb68b27c428d477169f3aa46c72dba103a17bd (diff) | |
download | linux-dfacc4d6c98b89609250269f518c1f54c30454ef.tar.xz |
Merge branch 'perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core
Diffstat (limited to 'kernel/perf_event.c')
-rw-r--r-- | kernel/perf_event.c | 58 |
1 files changed, 46 insertions, 12 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 7e3bcf1..2a060be 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -4050,19 +4050,46 @@ static inline u64 swevent_hash(u64 type, u32 event_id) return hash_64(val, SWEVENT_HLIST_BITS); } -static struct hlist_head * -find_swevent_head(struct perf_cpu_context *ctx, u64 type, u32 event_id) +static inline struct hlist_head * +__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) { - u64 hash; - struct swevent_hlist *hlist; + u64 hash = swevent_hash(type, event_id); + + return &hlist->heads[hash]; +} - hash = swevent_hash(type, event_id); +/* For the read side: events when they trigger */ +static inline struct hlist_head * +find_swevent_head_rcu(struct perf_cpu_context *ctx, u64 type, u32 event_id) +{ + struct swevent_hlist *hlist; hlist = rcu_dereference(ctx->swevent_hlist); if (!hlist) return NULL; - return &hlist->heads[hash]; + return __find_swevent_head(hlist, type, event_id); +} + +/* For the event head insertion and removal in the hlist */ +static inline struct hlist_head * +find_swevent_head(struct perf_cpu_context *ctx, struct perf_event *event) +{ + struct swevent_hlist *hlist; + u32 event_id = event->attr.config; + u64 type = event->attr.type; + + /* + * Event scheduling is always serialized against hlist allocation + * and release. Which makes the protected version suitable here. + * The context lock guarantees that. + */ + hlist = rcu_dereference_protected(ctx->swevent_hlist, + lockdep_is_held(&event->ctx->lock)); + if (!hlist) + return NULL; + + return __find_swevent_head(hlist, type, event_id); } static void do_perf_sw_event(enum perf_type_id type, u32 event_id, @@ -4079,7 +4106,7 @@ static void do_perf_sw_event(enum perf_type_id type, u32 event_id, rcu_read_lock(); - head = find_swevent_head(cpuctx, type, event_id); + head = find_swevent_head_rcu(cpuctx, type, event_id); if (!head) goto end; @@ -4162,7 +4189,7 @@ static int perf_swevent_enable(struct perf_event *event) perf_swevent_set_period(event); } - head = find_swevent_head(cpuctx, event->attr.type, event->attr.config); + head = find_swevent_head(cpuctx, event); if (WARN_ON_ONCE(!head)) return -EINVAL; @@ -4350,6 +4377,14 @@ static const struct pmu perf_ops_task_clock = { .read = task_clock_perf_event_read, }; +/* Deref the hlist from the update side */ +static inline struct swevent_hlist * +swevent_hlist_deref(struct perf_cpu_context *cpuctx) +{ + return rcu_dereference_protected(cpuctx->swevent_hlist, + lockdep_is_held(&cpuctx->hlist_mutex)); +} + static void swevent_hlist_release_rcu(struct rcu_head *rcu_head) { struct swevent_hlist *hlist; @@ -4360,12 +4395,11 @@ static void swevent_hlist_release_rcu(struct rcu_head *rcu_head) static void swevent_hlist_release(struct perf_cpu_context *cpuctx) { - struct swevent_hlist *hlist; + struct swevent_hlist *hlist = swevent_hlist_deref(cpuctx); - if (!cpuctx->swevent_hlist) + if (!hlist) return; - hlist = cpuctx->swevent_hlist; rcu_assign_pointer(cpuctx->swevent_hlist, NULL); call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu); } @@ -4402,7 +4436,7 @@ static int swevent_hlist_get_cpu(struct perf_event *event, int cpu) mutex_lock(&cpuctx->hlist_mutex); - if (!cpuctx->swevent_hlist && cpu_online(cpu)) { + if (!swevent_hlist_deref(cpuctx) && cpu_online(cpu)) { struct swevent_hlist *hlist; hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); |