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path: root/include/linux/marker.h
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2008-05-23Markers - define non optimized markerMathieu Desnoyers
To support the forthcoming "immediate values" marker optimization, we must have a way to declare markers in few code paths that does not use instruction modification based enable. This will be the case of printk(), some traps and eventually lockdep instrumentation. Changelog : - Fix reversed boolean logic of "generic". Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23Markers - remove extra format argumentMathieu Desnoyers
Denys Vlasenko <vda.linux@googlemail.com> : > Not in this patch, but I noticed: > > #define __trace_mark(name, call_private, format, args...) \ > do { \ > static const char __mstrtab_##name[] \ > __attribute__((section("__markers_strings"))) \ > = #name "\0" format; \ > static struct marker __mark_##name \ > __attribute__((section("__markers"), aligned(8))) = \ > { __mstrtab_##name, &__mstrtab_##name[sizeof(#name)], \ > 0, 0, marker_probe_cb, \ > { __mark_empty_function, NULL}, NULL }; \ > __mark_check_format(format, ## args); \ > if (unlikely(__mark_##name.state)) { \ > (*__mark_##name.call) \ > (&__mark_##name, call_private, \ > format, ## args); \ > } \ > } while (0) > > In this call: > > (*__mark_##name.call) \ > (&__mark_##name, call_private, \ > format, ## args); \ > > you make gcc allocate duplicate format string. You can use > &__mstrtab_##name[sizeof(#name)] instead since it holds the same string, > or drop ", format," above and "const char *fmt" from here: > > void (*call)(const struct marker *mdata, /* Probe wrapper */ > void *call_private, const char *fmt, ...); > > since mdata->format is the same and all callees which need it can take it there. Very good point. I actually thought about dropping it, since it would remove an unnecessary argument from the stack. And actually, since I now have the marker_probe_cb sitting between the marker site and the callbacks, there is no API change required. Thanks :) Mathieu Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> CC: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-03-05markers: add an if(0) to __mark_check_format()Mathieu Desnoyers
Wrap __mark_check_format() into an if(0) to make sure that parameters such as trace_mark(mm_page_alloc, "order %u pfn %lu", order, page?page_to_pfn(page):0); (where page_to_pfn() has side-effects) won't generate code because of the __mark_check_format(). Thanks to Jan Kiszka for reporting this. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: "Frank Ch. Eigler" <fche@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-14Linux Kernel Markers: create modpost fileMathieu Desnoyers
This adds some new magic in the MODPOST phase for CONFIG_MARKERS. Analogous to the Module.symvers file, the build will now write a Module.markers file when CONFIG_MARKERS=y is set. This file lists the name, defining module, and format string of each marker, separated by \t characters. This simple text file can be used by offline build procedures for instrumentation code, analogous to how System.map and Module.symvers can be useful to have for kernels other than the one you are running right now. The strings are made easy to extract by having the __trace_mark macro define the name and format together in a single array called __mstrtab_* in the __markers_strings section. This is straightforward and reliable as long as the marker structs are always defined by this macro. It is an unreasonable amount of hairy work to extract the string pointers from the __markers section structs, which entails handling a relocation type for every machine under the sun. Mathieu : - Ran through checkpatch.pl Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: David Smith <dsmith@redhat.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-14Linux Kernel Markers: support multiple probesMathieu Desnoyers
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>
2007-10-19Linux Kernel Markers - SamplesMathieu Desnoyers
Module example showing how to use the Linux Kernel Markers. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Linux Kernel MarkersMathieu Desnoyers
The marker activation functions sits in kernel/marker.c. A hash table is used to keep track of the registered probes and armed markers, so the markers within a newly loaded module that should be active can be activated at module load time. marker_query has been removed. marker_get_first, marker_get_next and marker_release should be used as iterators on the markers. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: "Frank Ch. Eigler" <fche@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Mike Mason <mmlnx@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>