---

yaml
---
r: 121151
b: refs/heads/master
c: 0c726da
h: refs/heads/master
i:
  121149: 1e1415c
  121147: 0856a00
  121143: aae4241
  121135: 45a1491
  121119: b0b545d
  121087: 0d6bdd5
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3f8e402f34ecc7d1d00b54703d3baa401b8bdd78
+refs/heads/master: 0c726da983de0704254250ef6495ca152e7abcca

trunk/Documentation/markers.txt

@@ -70,20 +70,6 @@ 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
 

trunk/Documentation/tracepoints.txt

@@ -3,30 +3,28 @@
 			    Mathieu Desnoyers
 
 
-This document introduces Linux Kernel Tracepoints and their use. It
-provides examples of how to insert tracepoints in the kernel and
-connect probe functions to them and provides some examples of probe
-functions.
+This document introduces Linux Kernel Tracepoints and their use. It provides
+examples of how to insert tracepoints in the kernel and connect probe functions
+to them and provides some examples of probe functions.
 
 
 * Purpose of tracepoints
 
-A tracepoint placed in code provides a hook to call a function (probe)
-that you can provide at runtime. A tracepoint can be "on" (a probe is
-connected to it) or "off" (no probe is attached). When a tracepoint is
-"off" it has no effect, except for adding a tiny time penalty
-(checking a condition for a branch) and space penalty (adding a few
-bytes for the function call at the end of the instrumented function
-and adds a data structure in a separate section).  When a tracepoint
-is "on", the function you provide is called each time the tracepoint
-is executed, in the execution context of the caller. When the function
-provided ends its execution, it returns to the caller (continuing from
-the tracepoint site).
+A tracepoint placed in code provides a hook to call a function (probe) that you
+can provide at runtime. A tracepoint can be "on" (a probe is connected to it) or
+"off" (no probe is attached). When a tracepoint is "off" it has no effect,
+except for adding a tiny time penalty (checking a condition for a branch) and
+space penalty (adding a few bytes for the function call at the end of the
+instrumented function and adds a data structure in a separate section).  When a
+tracepoint is "on", the function you provide is called each time the tracepoint
+is executed, in the execution context of the caller. When the function provided
+ends its execution, it returns to the caller (continuing from the tracepoint
+site).
 
 You can put tracepoints at important locations in the code. They are
 lightweight hooks that can pass an arbitrary number of parameters,
-which prototypes are described in a tracepoint declaration placed in a
-header file.
+which prototypes are described in a tracepoint declaration placed in a header
+file.
 
 They can be used for tracing and performance accounting.
 
@@ -44,16 +42,14 @@ In include/trace/subsys.h :
 
 #include <linux/tracepoint.h>
 
-DECLARE_TRACE(subsys_eventname,
+DEFINE_TRACE(subsys_eventname,
 	TPPTOTO(int firstarg, struct task_struct *p),
 	TPARGS(firstarg, p));
 
 In subsys/file.c (where the tracing statement must be added) :
 
 #include <trace/subsys.h>
 
-DEFINE_TRACE(subsys_eventname);
-
 void somefct(void)
 {
 	...
@@ -65,41 +61,31 @@ Where :
 - subsys_eventname is an identifier unique to your event
     - subsys is the name of your subsystem.
     - eventname is the name of the event to trace.
+- TPPTOTO(int firstarg, struct task_struct *p) is the prototype of the function
+  called by this tracepoint.
+- TPARGS(firstarg, p) are the parameters names, same as found in the prototype.
 
-- TPPTOTO(int firstarg, struct task_struct *p) is the prototype of the
-  function called by this tracepoint.
-
-- TPARGS(firstarg, p) are the parameters names, same as found in the
-  prototype.
-
-Connecting a function (probe) to a tracepoint is done by providing a
-probe (function to call) for the specific tracepoint through
+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.
-
-tracepoint_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 all the kernel to make sure no type conflict will
-occur. Name mangling of the tracepoints is done using the prototypes
-to make sure typing is correct. Verification of probe type correctness
-is done at the registration site by the compiler. Tracepoints can be
-put in inline functions, inlined static functions, and unrolled loops
-as well as regular functions.
-
-The naming scheme "subsys_event" is suggested here as a convention
-intended to limit collisions. Tracepoint names are global to the
-kernel: they are considered as being the same whether they are in the
-core kernel image or in modules.
-
-If the tracepoint has to be used in kernel modules, an
-EXPORT_TRACEPOINT_SYMBOL_GPL() or EXPORT_TRACEPOINT_SYMBOL() can be
-used to export the defined tracepoints.
+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.
+
+The tracepoint mechanism supports inserting multiple instances of the same
+tracepoint, but a single definition must be made of a given tracepoint name over
+all the kernel to make sure no type conflict will occur. Name mangling of the
+tracepoints is done using the prototypes to make sure typing is correct.
+Verification of probe type correctness is done at the registration site by the
+compiler. Tracepoints can be put in inline functions, inlined static functions,
+and unrolled loops as well as regular functions.
+
+The naming scheme "subsys_event" is suggested here as a convention intended
+to limit collisions. Tracepoint names are global to the kernel: they are
+considered as being the same whether they are in the core kernel image or in
+modules.
+
 
 * Probe / tracepoint example
 

trunk/arch/x86/include/asm/ftrace.h

@@ -17,14 +17,6 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
 	 */
 	return addr - 1;
 }
-
-#ifdef CONFIG_DYNAMIC_FTRACE
-
-struct dyn_arch_ftrace {
-	/* No extra data needed for x86 */
-};
-
-#endif /*  CONFIG_DYNAMIC_FTRACE */
 #endif /* __ASSEMBLY__ */
 #endif /* CONFIG_FUNCTION_TRACER */
 

trunk/arch/x86/kernel/entry_32.S

@@ -1190,7 +1190,7 @@ ENTRY(mcount)
 	jnz trace
 #ifdef CONFIG_FUNCTION_RET_TRACER
 	cmpl $ftrace_stub, ftrace_function_return
-	jnz ftrace_return_caller
+	jnz trace_return
 #endif
 .globl ftrace_stub
 ftrace_stub:
@@ -1211,15 +1211,9 @@ trace:
 	popl %ecx
 	popl %eax
 	jmp ftrace_stub
-END(mcount)
-#endif /* CONFIG_DYNAMIC_FTRACE */
-#endif /* CONFIG_FUNCTION_TRACER */
 
 #ifdef CONFIG_FUNCTION_RET_TRACER
-ENTRY(ftrace_return_caller)
-	cmpl $0, function_trace_stop
-	jne ftrace_stub
-
+trace_return:
 	pushl %eax
 	pushl %ecx
 	pushl %edx
@@ -1229,8 +1223,7 @@ ENTRY(ftrace_return_caller)
 	popl %edx
 	popl %ecx
 	popl %eax
-	ret
-END(ftrace_return_caller)
+	jmp ftrace_stub
 
 .globl return_to_handler
 return_to_handler:
@@ -1244,7 +1237,10 @@ return_to_handler:
 	popl %ecx
 	popl %eax
 	ret
-#endif
+#endif /* CONFIG_FUNCTION_RET_TRACER */
+END(mcount)
+#endif /* CONFIG_DYNAMIC_FTRACE */
+#endif /* CONFIG_FUNCTION_TRACER */
 
 .section .rodata,"a"
 #include "syscall_table_32.S"