When there's new data in the AUX space, output a record indicating its
offset and size and a set of flags, such as PERF_AUX_FLAG_TRUNCATED, to
mean the described data was truncated to fit in the ring buffer.
Signed-off-by: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <a...@infradead.org>
---
include/uapi/linux/perf_event.h | 19 +++++++++++++++++++
kernel/events/core.c | 34 ++++++++++++++++++++++++++++++++++
kernel/events/internal.h | 3 +++
3 files changed, 56 insertions(+)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 9a13e5fded..272258380e 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -733,6 +733,20 @@ enum perf_event_type {
*/
PERF_RECORD_MMAP2 = 10,
+ /*
+ * Records that new data landed in the AUX buffer part.
+ *
+ * struct {
+ * struct perf_event_header header;
+ *
+ * u64 aux_offset;
+ * u64 aux_size;
+ * u64 flags;
+ * struct sample_id sample_id;
+ * };
+ */
+ PERF_RECORD_AUX = 11,
+
PERF_RECORD_MAX, /* non-ABI */
};
@@ -750,6 +764,11 @@ enum perf_callchain_context {
PERF_CONTEXT_MAX = (__u64)-4095,
};
+/**
+ * PERF_RECORD_AUX::flags bits
+ */
+#define PERF_AUX_FLAG_TRUNCATED 0x01 /* record was truncated
to fit */
+
#define PERF_FLAG_FD_NO_GROUP (1UL << 0)
#define PERF_FLAG_FD_OUTPUT (1UL << 1)
#define PERF_FLAG_PID_CGROUP (1UL << 2) /* pid=cgroup id, per-cpu
mode only */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2399c12e49..779f60d300 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5606,6 +5606,40 @@ void perf_event_mmap(struct vm_area_struct *vma)
perf_event_mmap_event(&mmap_event);
}
+void perf_event_aux_event(struct perf_event *event, unsigned long head,
+ unsigned long size, u64 flags)
+{
+ struct perf_output_handle handle;
+ struct perf_sample_data sample;
+ struct perf_aux_event {
+ struct perf_event_header header;
+ u64 offset;
+ u64 size;
+ u64 flags;
+ } rec = {
+ .header = {
+ .type = PERF_RECORD_AUX,
+ .misc = 0,
+ .size = sizeof(rec),
+ },
+ .offset = head,
+ .size = size,
+ .flags = flags,
+ };
+ int ret;
+
+ perf_event_header__init_id(&rec.header, &sample, event);
+ ret = perf_output_begin(&handle, event, rec.header.size);
+
+ if (ret)
+ return;
+
+ perf_output_put(&handle, rec);
+ perf_event__output_id_sample(event, &handle, &sample);
+
+ perf_output_end(&handle);
+}
+
/*
* IRQ throttle logging
*/
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index 0f6d080159..4d117a9814 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -62,6 +62,9 @@ static inline bool rb_has_aux(struct ring_buffer *rb)
return !!rb->aux_nr_pages;
}
+void perf_event_aux_event(struct perf_event *event, unsigned long head,
+ unsigned long size, u64 flags);
+
extern void
perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
--
2.1.1
--
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