From f86977620ee4635f26befcf436700493a38ce002 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Fri, 1 Aug 2014 14:33:01 +0200 Subject: [PATCH] perf: Set owner pointer for kernel events Adding fake EVENT_OWNER_KERNEL owner pointer value for kernel perf events, so we could distinguish it from user events, which needs special care in following patch. Signed-off-by: Jiri Olsa Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Mark Rutland Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Mark Rutland Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1406896382-18404-3-git-send-email-jolsa@kernel.org Signed-off-by: Ingo Molnar --- kernel/events/core.c | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 1cf24b3e42ec..bbb3ca22f07c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -119,6 +119,13 @@ static int cpu_function_call(int cpu, int (*func) (void *info), void *info) return data.ret; } +#define EVENT_OWNER_KERNEL ((void *) -1) + +static bool is_kernel_event(struct perf_event *event) +{ + return event->owner == EVENT_OWNER_KERNEL; +} + #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ PERF_FLAG_FD_OUTPUT |\ PERF_FLAG_PID_CGROUP |\ @@ -3312,16 +3319,12 @@ static void free_event(struct perf_event *event) } /* - * Called when the last reference to the file is gone. + * Remove user event from the owner task. */ -static void put_event(struct perf_event *event) +static void perf_remove_from_owner(struct perf_event *event) { - struct perf_event_context *ctx = event->ctx; struct task_struct *owner; - if (!atomic_long_dec_and_test(&event->refcount)) - return; - rcu_read_lock(); owner = ACCESS_ONCE(event->owner); /* @@ -3354,6 +3357,20 @@ static void put_event(struct perf_event *event) mutex_unlock(&owner->perf_event_mutex); put_task_struct(owner); } +} + +/* + * Called when the last reference to the file is gone. + */ +static void put_event(struct perf_event *event) +{ + struct perf_event_context *ctx = event->ctx; + + if (!atomic_long_dec_and_test(&event->refcount)) + return; + + if (!is_kernel_event(event)) + perf_remove_from_owner(event); WARN_ON_ONCE(ctx->parent_ctx); /* @@ -7366,6 +7383,9 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, goto err; } + /* Mark owner so we could distinguish it from user events. */ + event->owner = EVENT_OWNER_KERNEL; + account_event(event); ctx = find_get_context(event->pmu, task, cpu); -- 2.30.2