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authorMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>2008-09-29 11:10:34 -0400
committerIngo Molnar <mingo@elte.hu>2008-10-14 10:38:33 +0200
commit91a8d46c47e7eb1c53c181e4328a3cfa45ae4ad3 (patch)
tree61a4f531bd68a386610d6ecaa520bda1d7c80174 /Documentation/markers.txt
parent531d297569014e8f889b167a2d15d72429faead1 (diff)
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markers: documentation fix for teardown
Document the need for a marker_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>
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1 files changed, 6 insertions, 4 deletions
diff --git a/Documentation/markers.txt b/Documentation/markers.txt
index d9f50a1..089f613 100644
--- a/Documentation/markers.txt
+++ b/Documentation/markers.txt
@@ -50,10 +50,12 @@ Connecting a function (probe) to a marker is done by providing a probe (function
to call) for the specific marker through marker_probe_register() and can be
activated by calling marker_arm(). Marker deactivation can be done by calling
marker_disarm() as many times as marker_arm() has been called. Removing a probe
-is done through marker_probe_unregister(); it will disarm the probe and make
-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.
+is done through marker_probe_unregister(); it will disarm 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 marker mechanism supports inserting multiple instances of the same marker.
Markers can be put in inline functions, inlined static functions, and
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