From aa6f5ffbdba45aa8e19e5048648fc6c7b25376d3 Mon Sep 17 00:00:00 2001 From: merge Date: Thu, 22 Jan 2009 13:55:32 +0000 Subject: MERGE-via-pending-tracking-hist-MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141 pending-tracking-hist top was MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141 / fdf777a63bcb59e0dfd78bfe2c6242e01f6d4eb9 ... parent commitmessage: From: merge MERGE-via-stable-tracking-hist-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 stable-tracking-hist top was MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 / 90463bfd2d5a3c8b52f6e6d71024a00e052b0ced ... parent commitmessage: From: merge MERGE-via-mokopatches-tracking-hist-fix-stray-endmenu-patch mokopatches-tracking-hist top was fix-stray-endmenu-patch / 3630e0be570de8057e7f8d2fe501ed353cdf34e6 ... parent commitmessage: From: Andy Green fix-stray-endmenu.patch Signed-off-by: Andy Green --- Documentation/markers.txt | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) (limited to 'Documentation/markers.txt') diff --git a/Documentation/markers.txt b/Documentation/markers.txt index 089f6138fcd..d2b3d0e91b2 100644 --- a/Documentation/markers.txt +++ b/Documentation/markers.txt @@ -51,11 +51,16 @@ 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. -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. + +marker_synchronize_unregister() must be called between probe unregistration and +the first occurrence of +- the end of module exit function, + to make sure there is no caller left using the probe; +- the free of any resource used by the probes, + to make sure the probes wont be accessing invalid data. +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 @@ -70,6 +75,20 @@ a printk warning which identifies the inconsistency: "Format mismatch for probe probe_name (format), marker (format)" +Another way to use markers is to simply define the marker without generating any +function call to actually call into the marker. This is useful in combination +with tracepoint probes in a scheme like this : + +void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk); + +DEFINE_MARKER_TP(marker_eventname, tracepoint_name, probe_tracepoint_name, + "arg1 %u pid %d"); + +notrace void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk) +{ + struct marker *marker = &GET_MARKER(kernel_irq_entry); + /* write data to trace buffers ... */ +} * Probe / marker example -- cgit v1.2.3