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author | Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> | 2008-02-13 15:03:37 -0800 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-13 16:21:20 -0800 |
commit | fb40bd78b0f91b274879cf5db8facd1e04b6052e (patch) | |
tree | 2347ccb5ad07f58ab5a4eb41174bb7b54d5f0c5b /samples/markers | |
parent | 9170d2f6e1dc4d79650fbf492d1cd45291c66504 (diff) | |
download | kernel_samsung_aries-fb40bd78b0f91b274879cf5db8facd1e04b6052e.zip kernel_samsung_aries-fb40bd78b0f91b274879cf5db8facd1e04b6052e.tar.gz kernel_samsung_aries-fb40bd78b0f91b274879cf5db8facd1e04b6052e.tar.bz2 |
Linux Kernel Markers: support multiple probes
RCU style multiple probes support for the Linux Kernel Markers. Common case
(one probe) is still fast and does not require dynamic allocation or a
supplementary pointer dereference on the fast path.
- Move preempt disable from the marker site to the callback.
Since we now have an internal callback, move the preempt disable/enable to the
callback instead of the marker site.
Since the callback change is done asynchronously (passing from a handler that
supports arguments to a handler that does not setup the arguments is no
arguments are passed), we can safely update it even if it is outside the
preempt disable section.
- Move probe arm to probe connection. Now, a connected probe is automatically
armed.
Remove MARK_MAX_FORMAT_LEN, unused.
This patch modifies the Linux Kernel Markers API : it removes the probe
"arm/disarm" and changes the probe function prototype : it now expects a
va_list * instead of a "...".
If we want to have more than one probe connected to a marker at a given
time (LTTng, or blktrace, ssytemtap) then we need this patch. Without it,
connecting a second probe handler to a marker will fail.
It allow us, for instance, to do interesting combinations :
Do standard tracing with LTTng and, eventually, to compute statistics
with SystemTAP, or to have a special trigger on an event that would call
a systemtap script which would stop flight recorder tracing.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Mason <mmlnx@us.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: David Smith <dsmith@redhat.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'samples/markers')
-rw-r--r-- | samples/markers/probe-example.c | 25 |
1 files changed, 9 insertions, 16 deletions
diff --git a/samples/markers/probe-example.c b/samples/markers/probe-example.c index a367975..c8e099d 100644 --- a/samples/markers/probe-example.c +++ b/samples/markers/probe-example.c @@ -20,31 +20,27 @@ struct probe_data { marker_probe_func *probe_func; }; -void probe_subsystem_event(const struct marker *mdata, void *private, - const char *format, ...) +void probe_subsystem_event(void *probe_data, void *call_data, + const char *format, va_list *args) { - va_list ap; /* Declare args */ unsigned int value; const char *mystr; /* Assign args */ - va_start(ap, format); - value = va_arg(ap, typeof(value)); - mystr = va_arg(ap, typeof(mystr)); + value = va_arg(*args, typeof(value)); + mystr = va_arg(*args, typeof(mystr)); /* Call printk */ - printk(KERN_DEBUG "Value %u, string %s\n", value, mystr); + printk(KERN_INFO "Value %u, string %s\n", value, mystr); /* or count, check rights, serialize data in a buffer */ - - va_end(ap); } atomic_t eventb_count = ATOMIC_INIT(0); -void probe_subsystem_eventb(const struct marker *mdata, void *private, - const char *format, ...) +void probe_subsystem_eventb(void *probe_data, void *call_data, + const char *format, va_list *args) { /* Increment counter */ atomic_inc(&eventb_count); @@ -72,10 +68,6 @@ static int __init probe_init(void) if (result) printk(KERN_INFO "Unable to register probe %s\n", probe_array[i].name); - result = marker_arm(probe_array[i].name); - if (result) - printk(KERN_INFO "Unable to arm probe %s\n", - probe_array[i].name); } return 0; } @@ -85,7 +77,8 @@ static void __exit probe_fini(void) int i; for (i = 0; i < ARRAY_SIZE(probe_array); i++) - marker_probe_unregister(probe_array[i].name); + marker_probe_unregister(probe_array[i].name, + probe_array[i].probe_func, &probe_array[i]); printk(KERN_INFO "Number of event b : %u\n", atomic_read(&eventb_count)); } |