From 72c696e8fb82949915fe107851169fdea87ae8bc Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C3=A9r=C3=A9mie=20Galarneau?= Date: Wed, 12 Jan 2022 12:43:07 -0500 Subject: [PATCH] Docs: relayd: document the role of session_trace_chunk_registry MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Signed-off-by: Jérémie Galarneau Change-Id: I6158dadfe92d23c0081aac888c3e54b3c9c711a3 --- src/bin/lttng-relayd/sessiond-trace-chunks.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/src/bin/lttng-relayd/sessiond-trace-chunks.h b/src/bin/lttng-relayd/sessiond-trace-chunks.h index f2bc5a382..2c771d809 100644 --- a/src/bin/lttng-relayd/sessiond-trace-chunks.h +++ b/src/bin/lttng-relayd/sessiond-trace-chunks.h @@ -12,6 +12,17 @@ #include #include +/* + * A session trace chunk registry allows the relay daemon to share trace chunks + * used by different "relay sessions" when they were created for the same + * user-visible session daemon session. Tracing multiple domains (e.g. ust and + * kernel) results in per-domain relay sessions being created. + * + * Sharing trace chunks, and their output directory more specifically, is + * essential to properly implement session rotations. The sharing of output + * directory handles allows directory renames to be performed once and without + * races that would stem from from multiple renames. + */ struct sessiond_trace_chunk_registry; struct sessiond_trace_chunk_registry * -- 2.34.1