perf events: Precalculate the header space for PERF_SAMPLE_ fields
PERF_SAMPLE_{CALLCHAIN,RAW} have variable lenghts per sample, but the others can be precalculated, reducing a bit the per sample cost. Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ian Munsie <imunsie@au1.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> LKML-Reference: <new-submission> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@ -758,6 +758,8 @@ struct perf_event {
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u64 shadow_ctx_time;
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struct perf_event_attr attr;
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u16 header_size;
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u16 read_size;
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struct hw_perf_event hw;
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struct perf_event_context *ctx;
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@ -312,9 +312,75 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx)
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ctx->nr_stat++;
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}
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/*
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* Called at perf_event creation and when events are attached/detached from a
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* group.
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*/
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static void perf_event__read_size(struct perf_event *event)
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{
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int entry = sizeof(u64); /* value */
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int size = 0;
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int nr = 1;
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if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
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size += sizeof(u64);
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if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
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size += sizeof(u64);
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if (event->attr.read_format & PERF_FORMAT_ID)
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entry += sizeof(u64);
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if (event->attr.read_format & PERF_FORMAT_GROUP) {
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nr += event->group_leader->nr_siblings;
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size += sizeof(u64);
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}
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size += entry * nr;
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event->read_size = size;
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}
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static void perf_event__header_size(struct perf_event *event)
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{
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struct perf_sample_data *data;
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u64 sample_type = event->attr.sample_type;
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u16 size = 0;
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perf_event__read_size(event);
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if (sample_type & PERF_SAMPLE_IP)
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size += sizeof(data->ip);
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if (sample_type & PERF_SAMPLE_TID)
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size += sizeof(data->tid_entry);
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if (sample_type & PERF_SAMPLE_TIME)
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size += sizeof(data->time);
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if (sample_type & PERF_SAMPLE_ADDR)
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size += sizeof(data->addr);
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if (sample_type & PERF_SAMPLE_ID)
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size += sizeof(data->id);
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if (sample_type & PERF_SAMPLE_STREAM_ID)
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size += sizeof(data->stream_id);
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if (sample_type & PERF_SAMPLE_CPU)
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size += sizeof(data->cpu_entry);
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if (sample_type & PERF_SAMPLE_PERIOD)
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size += sizeof(data->period);
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if (sample_type & PERF_SAMPLE_READ)
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size += event->read_size;
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event->header_size = size;
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}
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static void perf_group_attach(struct perf_event *event)
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{
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struct perf_event *group_leader = event->group_leader;
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struct perf_event *group_leader = event->group_leader, *pos;
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/*
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* We can have double attach due to group movement in perf_event_open.
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@ -333,6 +399,11 @@ static void perf_group_attach(struct perf_event *event)
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list_add_tail(&event->group_entry, &group_leader->sibling_list);
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group_leader->nr_siblings++;
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perf_event__header_size(group_leader);
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list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
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perf_event__header_size(pos);
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}
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/*
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@ -391,7 +462,7 @@ static void perf_group_detach(struct perf_event *event)
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if (event->group_leader != event) {
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list_del_init(&event->group_entry);
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event->group_leader->nr_siblings--;
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return;
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goto out;
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}
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if (!list_empty(&event->group_entry))
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@ -410,6 +481,12 @@ static void perf_group_detach(struct perf_event *event)
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/* Inherit group flags from the previous leader */
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sibling->group_flags = event->group_flags;
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}
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out:
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perf_event__header_size(event->group_leader);
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list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
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perf_event__header_size(tmp);
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}
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static inline int
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@ -2289,31 +2366,6 @@ static int perf_release(struct inode *inode, struct file *file)
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return perf_event_release_kernel(event);
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}
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static int perf_event_read_size(struct perf_event *event)
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{
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int entry = sizeof(u64); /* value */
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int size = 0;
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int nr = 1;
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if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
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size += sizeof(u64);
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if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
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size += sizeof(u64);
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if (event->attr.read_format & PERF_FORMAT_ID)
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entry += sizeof(u64);
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if (event->attr.read_format & PERF_FORMAT_GROUP) {
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nr += event->group_leader->nr_siblings;
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size += sizeof(u64);
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}
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size += entry * nr;
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return size;
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}
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u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
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{
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struct perf_event *child;
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@ -2428,7 +2480,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
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if (event->state == PERF_EVENT_STATE_ERROR)
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return 0;
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if (count < perf_event_read_size(event))
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if (count < event->read_size)
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return -ENOSPC;
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WARN_ON_ONCE(event->ctx->parent_ctx);
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@ -3606,59 +3658,34 @@ void perf_prepare_sample(struct perf_event_header *header,
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data->type = sample_type;
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header->type = PERF_RECORD_SAMPLE;
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header->size = sizeof(*header);
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header->size = sizeof(*header) + event->header_size;
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header->misc = 0;
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header->misc |= perf_misc_flags(regs);
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if (sample_type & PERF_SAMPLE_IP) {
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if (sample_type & PERF_SAMPLE_IP)
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data->ip = perf_instruction_pointer(regs);
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header->size += sizeof(data->ip);
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}
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if (sample_type & PERF_SAMPLE_TID) {
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/* namespace issues */
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data->tid_entry.pid = perf_event_pid(event, current);
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data->tid_entry.tid = perf_event_tid(event, current);
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header->size += sizeof(data->tid_entry);
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}
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if (sample_type & PERF_SAMPLE_TIME) {
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if (sample_type & PERF_SAMPLE_TIME)
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data->time = perf_clock();
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header->size += sizeof(data->time);
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}
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if (sample_type & PERF_SAMPLE_ADDR)
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header->size += sizeof(data->addr);
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if (sample_type & PERF_SAMPLE_ID) {
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if (sample_type & PERF_SAMPLE_ID)
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data->id = primary_event_id(event);
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header->size += sizeof(data->id);
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}
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if (sample_type & PERF_SAMPLE_STREAM_ID) {
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if (sample_type & PERF_SAMPLE_STREAM_ID)
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data->stream_id = event->id;
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header->size += sizeof(data->stream_id);
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}
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if (sample_type & PERF_SAMPLE_CPU) {
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data->cpu_entry.cpu = raw_smp_processor_id();
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data->cpu_entry.reserved = 0;
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header->size += sizeof(data->cpu_entry);
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}
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if (sample_type & PERF_SAMPLE_PERIOD)
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header->size += sizeof(data->period);
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if (sample_type & PERF_SAMPLE_READ)
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header->size += perf_event_read_size(event);
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if (sample_type & PERF_SAMPLE_CALLCHAIN) {
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int size = 1;
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@ -3726,7 +3753,7 @@ perf_event_read_event(struct perf_event *event,
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.header = {
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.type = PERF_RECORD_READ,
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.misc = 0,
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.size = sizeof(read_event) + perf_event_read_size(event),
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.size = sizeof(read_event) + event->read_size,
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},
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.pid = perf_event_pid(event, task),
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.tid = perf_event_tid(event, task),
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@ -5714,6 +5741,11 @@ SYSCALL_DEFINE5(perf_event_open,
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list_add_tail(&event->owner_entry, ¤t->perf_event_list);
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mutex_unlock(¤t->perf_event_mutex);
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/*
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* Precalculate sample_data sizes
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*/
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perf_event__header_size(event);
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/*
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* Drop the reference on the group_event after placing the
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* new event on the sibling_list. This ensures destruction
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