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author | Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> | 2008-11-14 22:47:48 (GMT) |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-11-16 08:01:37 (GMT) |
commit | 8fd88d159031bd238dad1d7186a2030b9f9349de (patch) | |
tree | f5ab2ddfd747ee0dd6e4e9555671ff6b7d0dca0b /Documentation | |
parent | 7e066fb870fcd1025ec3ba7bbde5d541094f4ce1 (diff) | |
download | linux-fsl-qoriq-8fd88d159031bd238dad1d7186a2030b9f9349de.tar.xz |
tracepoints: documentation fix for teardown
Impact: documentation update
Need a tracepoint_synchronize_unregister() before the end of exit()
to make sure every probe callers have exited the non preemptible
section and thus are not executing the probe code anymore.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/tracepoints.txt | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/Documentation/tracepoints.txt b/Documentation/tracepoints.txt index e8ad47b..93cd90e 100644 --- a/Documentation/tracepoints.txt +++ b/Documentation/tracepoints.txt @@ -70,10 +70,12 @@ Where : Connecting a function (probe) to a tracepoint is done by providing a probe (function to call) for the specific tracepoint through register_trace_subsys_eventname(). Removing a probe is done through -unregister_trace_subsys_eventname(); it will remove the probe sure there is no -caller left using the probe when it returns. Probe removal is preempt-safe -because preemption is disabled around the probe call. See the "Probe example" -section below for a sample probe module. +unregister_trace_subsys_eventname(); it will remove the probe. +marker_synchronize_unregister() must be called before the end of the module exit +function to make sure there is no caller left using the probe. This, and the +fact that preemption is disabled around the probe call, make sure that probe +removal and module unload are safe. See the "Probe example" section below for a +sample probe module. The tracepoint mechanism supports inserting multiple instances of the same tracepoint, but a single definition must be made of a given tracepoint name over |