From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Beau Belgrave <beaub@linux.microsoft.com>
Subject: [for-linus][PATCH 15/15] tracing/user_events: Document auto-cleanup and remove dyn_event refs
Date: Thu, 15 Jun 2023 09:05:46 -0400 [thread overview]
Message-ID: <20230615133417.709819338@goodmis.org> (raw)
In-Reply-To: 20230615130531.200384328@goodmis.org
From: Beau Belgrave <beaub@linux.microsoft.com>
Now user_events auto-cleanup upon the last reference by default. This
makes it not possible to use the dynamics event file via tracefs.
Document that auto-cleanup is enabled by default and remove the refernce
to /sys/kernel/tracing/dynamic_events file to make this clear.
Link: https://lkml.kernel.org/r/20230614163336.5797-7-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Documentation/trace/user_events.rst | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/Documentation/trace/user_events.rst b/Documentation/trace/user_events.rst
index f79987e16cf4..e7b07313550a 100644
--- a/Documentation/trace/user_events.rst
+++ b/Documentation/trace/user_events.rst
@@ -14,10 +14,6 @@ Programs can view status of the events via
/sys/kernel/tracing/user_events_status and can both register and write
data out via /sys/kernel/tracing/user_events_data.
-Programs can also use /sys/kernel/tracing/dynamic_events to register and
-delete user based events via the u: prefix. The format of the command to
-dynamic_events is the same as the ioctl with the u: prefix applied.
-
Typically programs will register a set of events that they wish to expose to
tools that can read trace_events (such as ftrace and perf). The registration
process tells the kernel which address and bit to reflect if any tool has
@@ -144,6 +140,9 @@ its name. Delete will only succeed if there are no references left to the
event (in both user and kernel space). User programs should use a separate file
to request deletes than the one used for registration due to this.
+**NOTE:** By default events will auto-delete when there are no references left
+to the event. Flags in the future may change this logic.
+
Unregistering
-------------
If after registering an event it is no longer wanted to be updated then it can
--
2.39.2
prev parent reply other threads:[~2023-06-15 13:36 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-15 13:05 [for-linus][PATCH 00/15] tracing: Updates for 6.4 Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 01/15] tracing/rv/rtla: Update MAINTAINERS file to point to proper mailing list Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 02/15] tracing/user_events: Prevent same name but different args event Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 03/15] tracing/user_events: Handle matching arguments that is null from dyn_events Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 04/15] tracing: Modify print_fields() for fields output order Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 05/15] tracing/user_events: Fix the incorrect trace record for empty arguments events Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 06/15] selftests/user_events: Add ftrace self-test " Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 07/15] selftests/user_events: Clear the events after perf self-test Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 08/15] selftests/user_events: Add perf self-test for empty arguments events Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 09/15] tracing/user_events: Remove user_ns walk for groups Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 10/15] tracing/user_events: Store register flags on events Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 11/15] tracing/user_events: Track refcount consistently via put/get Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 12/15] tracing/user_events: Add auto cleanup and future persist flag Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 13/15] selftests/user_events: Ensure auto cleanup works as expected Steven Rostedt
2023-06-15 13:05 ` [for-linus][PATCH 14/15] selftests/user_events: Adapt dyn_test to non-persist events Steven Rostedt
2023-06-15 13:05 ` Steven Rostedt [this message]
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