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1 Tracelevel
2
3 Documentation by Alon Farchy
4
51. Overview
6===========
7
8Tracelevel allows subsystem authors to add trace priorities to
9their tracing events. High priority traces will be enabled
10automatically at boot time.
11
12This module is configured with CONFIG_TRACELEVEL.
13
142. Usage
15=========
16
17To give an event a priority, use the function tracelevel_register
18at any time.
19
20 tracelevel_register(my_event, level);
21
22my_event corresponds directly to the event name as defined in the
23event header file. Available levels are:
24
25 TRACELEVEL_ERR 3
26 TRACELEVEL_WARN 2
27 TRACELEVEL_INFO 1
28 TRACELEVEL_DEBUG 0
29
30Any event registered at boot time as TRACELEVEL_ERR will be enabled
31by default. The header also exposes the function tracelevel_set_level
32to change the trace level at runtime. Any trace event registered with the
33specified level or higher will be enabled with this call.
34
35A userspace handle to tracelevel_set_level is available via the module
36parameter 'level'. For example,
37
38 echo 1 > /sys/module/tracelevel/parameters/level
39
40Is logically equivalent to:
41
42 tracelevel_set_level(TRACELEVEL_INFO);