Merge branches 'tracing/blktrace', 'tracing/ftrace', 'tracing/function-graph-tracer' and 'tracing/power-tracer' into tracing/core

Author: Ingo Molnar

Documentation/ftrace.txt

@@ -127,6 +127,8 @@ of ftrace. Here is a list of some of the key files:
 		be traced. If a function exists in both set_ftrace_filter
 		and set_ftrace_notrace,	the function will _not_ be traced.
 
+  set_ftrace_pid: Have the function tracer only trace a single thread.
+
   available_filter_functions: This lists the functions that ftrace
 		has processed and can trace. These are the function
 		names that you can pass to "set_ftrace_filter" or
@@ -1073,6 +1075,83 @@ For simple one time traces, the above is sufficent. For anything else,
 a search through /proc/mounts may be needed to find where the debugfs
 file-system is mounted.
 
+
+Single thread tracing
+---------------------
+
+By writing into /debug/tracing/set_ftrace_pid you can trace a
+single thread. For example:
+
+# cat /debug/tracing/set_ftrace_pid
+no pid
+# echo 3111 > /debug/tracing/set_ftrace_pid
+# cat /debug/tracing/set_ftrace_pid
+3111
+# echo function > /debug/tracing/current_tracer
+# cat /debug/tracing/trace | head
+ # tracer: function
+ #
+ #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
+ #              | |       |          |         |
+     yum-updatesd-3111  [003]  1637.254676: finish_task_switch <-thread_return
+     yum-updatesd-3111  [003]  1637.254681: hrtimer_cancel <-schedule_hrtimeout_range
+     yum-updatesd-3111  [003]  1637.254682: hrtimer_try_to_cancel <-hrtimer_cancel
+     yum-updatesd-3111  [003]  1637.254683: lock_hrtimer_base <-hrtimer_try_to_cancel
+     yum-updatesd-3111  [003]  1637.254685: fget_light <-do_sys_poll
+     yum-updatesd-3111  [003]  1637.254686: pipe_poll <-do_sys_poll
+# echo -1 > /debug/tracing/set_ftrace_pid
+# cat /debug/tracing/trace |head
+ # tracer: function
+ #
+ #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
+ #              | |       |          |         |
+ ##### CPU 3 buffer started ####
+     yum-updatesd-3111  [003]  1701.957688: free_poll_entry <-poll_freewait
+     yum-updatesd-3111  [003]  1701.957689: remove_wait_queue <-free_poll_entry
+     yum-updatesd-3111  [003]  1701.957691: fput <-free_poll_entry
+     yum-updatesd-3111  [003]  1701.957692: audit_syscall_exit <-sysret_audit
+     yum-updatesd-3111  [003]  1701.957693: path_put <-audit_syscall_exit
+
+If you want to trace a function when executing, you could use
+something like this simple program:
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+int main (int argc, char **argv)
+{
+        if (argc < 1)
+                exit(-1);
+
+        if (fork() > 0) {
+                int fd, ffd;
+                char line[64];
+                int s;
+
+                ffd = open("/debug/tracing/current_tracer", O_WRONLY);
+                if (ffd < 0)
+                        exit(-1);
+                write(ffd, "nop", 3);
+
+                fd = open("/debug/tracing/set_ftrace_pid", O_WRONLY);
+                s = sprintf(line, "%d\n", getpid());
+                write(fd, line, s);
+
+                write(ffd, "function", 8);
+
+                close(fd);
+                close(ffd);
+
+                execvp(argv[1], argv+1);
+        }
+
+        return 0;
+}
+
 dynamic ftrace
 --------------
 

arch/x86/Kconfig

@@ -29,7 +29,7 @@ config X86
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_FUNCTION_TRACER
-	select HAVE_FUNCTION_RET_TRACER if X86_32
+	select HAVE_FUNCTION_GRAPH_TRACER if X86_32
 	select HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
 	select HAVE_ARCH_KGDB if !X86_VOYAGER

arch/x86/include/asm/ftrace.h

@@ -28,7 +28,7 @@ struct dyn_arch_ftrace {
 #endif /* __ASSEMBLY__ */
 #endif /* CONFIG_FUNCTION_TRACER */
 
-#ifdef CONFIG_FUNCTION_RET_TRACER
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 #ifndef __ASSEMBLY__
 
@@ -51,6 +51,6 @@ struct ftrace_ret_stack {
 extern void return_to_handler(void);
 
 #endif /* __ASSEMBLY__ */
-#endif /* CONFIG_FUNCTION_RET_TRACER */
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 #endif /* _ASM_X86_FTRACE_H */

arch/x86/kernel/Makefile

@@ -14,7 +14,7 @@ CFLAGS_REMOVE_paravirt-spinlocks.o = -pg
 CFLAGS_REMOVE_ftrace.o = -pg
 endif
 
-ifdef CONFIG_FUNCTION_RET_TRACER
+ifdef CONFIG_FUNCTION_GRAPH_TRACER
 # Don't trace __switch_to() but let it for function tracer
 CFLAGS_REMOVE_process_32.o = -pg
 endif
@@ -70,7 +70,7 @@ obj-$(CONFIG_X86_LOCAL_APIC)	+= apic.o nmi.o
 obj-$(CONFIG_X86_IO_APIC)	+= io_apic.o
 obj-$(CONFIG_X86_REBOOTFIXUPS)	+= reboot_fixups_32.o
 obj-$(CONFIG_DYNAMIC_FTRACE)	+= ftrace.o
-obj-$(CONFIG_FUNCTION_RET_TRACER)	+= ftrace.o
+obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec_$(BITS).o
 obj-$(CONFIG_KEXEC)		+= relocate_kernel_$(BITS).o crash.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump_$(BITS).o

arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c

@@ -33,6 +33,7 @@
 #include <linux/cpufreq.h>
 #include <linux/compiler.h>
 #include <linux/dmi.h>
+#include <linux/ftrace.h>
 
 #include <linux/acpi.h>
 #include <acpi/processor.h>
@@ -391,6 +392,7 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy,
 	unsigned int next_perf_state = 0; /* Index into perf table */
 	unsigned int i;
 	int result = 0;
+	struct power_trace it;
 
 	dprintk("acpi_cpufreq_target %d (%d)\n", target_freq, policy->cpu);
 
@@ -427,6 +429,8 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy,
 		}
 	}
 
+	trace_power_mark(&it, POWER_PSTATE, next_perf_state);
+
 	switch (data->cpu_feature) {
 	case SYSTEM_INTEL_MSR_CAPABLE:
 		cmd.type = SYSTEM_INTEL_MSR_CAPABLE;

arch/x86/kernel/entry_32.S

@@ -1174,6 +1174,11 @@ ftrace_call:
 	popl %edx
 	popl %ecx
 	popl %eax
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+.globl ftrace_graph_call
+ftrace_graph_call:
+	jmp ftrace_stub
+#endif
 
 .globl ftrace_stub
 ftrace_stub:
@@ -1188,9 +1193,9 @@ ENTRY(mcount)
 
 	cmpl $ftrace_stub, ftrace_trace_function
 	jnz trace
-#ifdef CONFIG_FUNCTION_RET_TRACER
-	cmpl $ftrace_stub, ftrace_function_return
-	jnz ftrace_return_caller
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	cmpl $ftrace_stub, ftrace_graph_return
+	jnz ftrace_graph_caller
 #endif
 .globl ftrace_stub
 ftrace_stub:
@@ -1215,8 +1220,8 @@ END(mcount)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 #endif /* CONFIG_FUNCTION_TRACER */
 
-#ifdef CONFIG_FUNCTION_RET_TRACER
-ENTRY(ftrace_return_caller)
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ENTRY(ftrace_graph_caller)
 	cmpl $0, function_trace_stop
 	jne ftrace_stub
 
@@ -1230,7 +1235,7 @@ ENTRY(ftrace_return_caller)
 	popl %ecx
 	popl %eax
 	ret
-END(ftrace_return_caller)
+END(ftrace_graph_caller)
 
 .globl return_to_handler
 return_to_handler:

arch/x86/kernel/ftrace.c

@@ -111,7 +111,6 @@ static void ftrace_mod_code(void)
 	 */
 	mod_code_status = probe_kernel_write(mod_code_ip, mod_code_newcode,
 					     MCOUNT_INSN_SIZE);
-
 }
 
 void ftrace_nmi_enter(void)
@@ -323,9 +322,53 @@ int __init ftrace_dyn_arch_init(void *data)
 }
 #endif
 
-#ifdef CONFIG_FUNCTION_RET_TRACER
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern void ftrace_graph_call(void);
+
+static int ftrace_mod_jmp(unsigned long ip,
+			  int old_offset, int new_offset)
+{
+	unsigned char code[MCOUNT_INSN_SIZE];
+
+	if (probe_kernel_read(code, (void *)ip, MCOUNT_INSN_SIZE))
+		return -EFAULT;
+
+	if (code[0] != 0xe9 || old_offset != *(int *)(&code[1]))
+		return -EINVAL;
+
+	*(int *)(&code[1]) = new_offset;
+
+	if (do_ftrace_mod_code(ip, &code))
+		return -EPERM;
+
+	return 0;
+}
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+	unsigned long ip = (unsigned long)(&ftrace_graph_call);
+	int old_offset, new_offset;
+
+	old_offset = (unsigned long)(&ftrace_stub) - (ip + MCOUNT_INSN_SIZE);
+	new_offset = (unsigned long)(&ftrace_graph_caller) - (ip + MCOUNT_INSN_SIZE);
+
+	return ftrace_mod_jmp(ip, old_offset, new_offset);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+	unsigned long ip = (unsigned long)(&ftrace_graph_call);
+	int old_offset, new_offset;
+
+	old_offset = (unsigned long)(&ftrace_graph_caller) - (ip + MCOUNT_INSN_SIZE);
+	new_offset = (unsigned long)(&ftrace_stub) - (ip + MCOUNT_INSN_SIZE);
+
+	return ftrace_mod_jmp(ip, old_offset, new_offset);
+}
 
-#ifndef CONFIG_DYNAMIC_FTRACE
+#else /* CONFIG_DYNAMIC_FTRACE */
 
 /*
  * These functions are picked from those used on
@@ -343,11 +386,12 @@ void ftrace_nmi_exit(void)
 {
 	atomic_dec(&in_nmi);
 }
+
 #endif /* !CONFIG_DYNAMIC_FTRACE */
 
 /* Add a function return address to the trace stack on thread info.*/
 static int push_return_trace(unsigned long ret, unsigned long long time,
-				unsigned long func)
+				unsigned long func, int *depth)
 {
 	int index;
 
@@ -365,21 +409,22 @@ static int push_return_trace(unsigned long ret, unsigned long long time,
 	current->ret_stack[index].ret = ret;
 	current->ret_stack[index].func = func;
 	current->ret_stack[index].calltime = time;
+	*depth = index;
 
 	return 0;
 }
 
 /* Retrieve a function return address to the trace stack on thread info.*/
-static void pop_return_trace(unsigned long *ret, unsigned long long *time,
-				unsigned long *func, unsigned long *overrun)
+static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
 {
 	int index;
 
 	index = current->curr_ret_stack;
 	*ret = current->ret_stack[index].ret;
-	*func = current->ret_stack[index].func;
-	*time = current->ret_stack[index].calltime;
-	*overrun = atomic_read(&current->trace_overrun);
+	trace->func = current->ret_stack[index].func;
+	trace->calltime = current->ret_stack[index].calltime;
+	trace->overrun = atomic_read(&current->trace_overrun);
+	trace->depth = index;
 	current->curr_ret_stack--;
 }
 
@@ -389,13 +434,14 @@ static void pop_return_trace(unsigned long *ret, unsigned long long *time,
  */
 unsigned long ftrace_return_to_handler(void)
 {
-	struct ftrace_retfunc trace;
-	pop_return_trace(&trace.ret, &trace.calltime, &trace.func,
-			&trace.overrun);
+	struct ftrace_graph_ret trace;
+	unsigned long ret;
+
+	pop_return_trace(&trace, &ret);
 	trace.rettime = cpu_clock(raw_smp_processor_id());
-	ftrace_function_return(&trace);
+	ftrace_graph_return(&trace);
 
-	return trace.ret;
+	return ret;
 }
 
 /*
@@ -407,6 +453,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 	unsigned long old;
 	unsigned long long calltime;
 	int faulted;
+	struct ftrace_graph_ent trace;
 	unsigned long return_hooker = (unsigned long)
 				&return_to_handler;
 
@@ -440,20 +487,27 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 	);
 
 	if (WARN_ON(faulted)) {
-		unregister_ftrace_return();
+		unregister_ftrace_graph();
 		return;
 	}
 
 	if (WARN_ON(!__kernel_text_address(old))) {
-		unregister_ftrace_return();
+		unregister_ftrace_graph();
 		*parent = old;
 		return;
 	}
 
 	calltime = cpu_clock(raw_smp_processor_id());
 
-	if (push_return_trace(old, calltime, self_addr) == -EBUSY)
+	if (push_return_trace(old, calltime,
+				self_addr, &trace.depth) == -EBUSY) {
 		*parent = old;
+		return;
+	}
+
+	trace.func = self_addr;
+	ftrace_graph_entry(&trace);
+
 }
 
-#endif /* CONFIG_FUNCTION_RET_TRACER */
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */