Re: [PATCH v12 2/6] ring-buffer: Introducing ring-buffer mapping functions
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2024-01-23 15:50:20
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On Tue, 23 Jan 2024 11:07:53 +0000 Vincent Donnefort [off-list ref] wrote:
quoted hunk ↗ jump to hunk
index 000000000000..5468afc94be7--- /dev/null +++ b/include/uapi/linux/trace_mmap.h@@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _TRACE_MMAP_H_ +#define _TRACE_MMAP_H_ + +#include <linux/types.h> + +/** + * struct trace_buffer_meta - Ring-buffer Meta-page description + * @meta_page_size: Size of this meta-page. + * @meta_struct_len: Size of this structure. + * @subbuf_size: Size of each subbuf, including the header. + * @nr_subbufs: Number of subbfs in the ring-buffer. + * @reader.lost_events: Number of events lost at the time of the reader swap. + * @reader.id: subbuf ID of the current reader. From 0 to @nr_subbufs - 1 + * @reader.read: Number of bytes read on the reader subbuf. + * @entries: Number of entries in the ring-buffer. + * @overrun: Number of entries lost in the ring-buffer. + * @read: Number of entries that have been read.
+ * @subbufs_touched: Number of subbufs that have been filled. + * @subbufs_lost: Number of subbufs lost to overrun. + * @subbufs_read: Number of subbufs that have been read.
Do we actually need the above 3 fields? What's the use case for them? I don't want to expose internals in the API unless they are needed. -- Steve