---

yaml
---
r: 141004
b: refs/heads/master
c: 09c9e84
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0cf53ff62b3e9e491ff5e5f05b193fb6ce643047
+refs/heads/master: 09c9e84d474d917d9de5b9011ed2064b03a19677

trunk/arch/x86/kernel/ftrace.c

@@ -79,11 +79,11 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
  *
  * 1) Put the instruction pointer into the IP buffer
  *    and the new code into the "code" buffer.
- * 2) Wait for any running NMIs to finish and set a flag that says
- *    we are modifying code, it is done in an atomic operation.
- * 3) Write the code
- * 4) clear the flag.
- * 5) Wait for any running NMIs to finish.
+ * 2) Set a flag that says we are modifying code
+ * 3) Wait for any running NMIs to finish.
+ * 4) Write the code
+ * 5) clear the flag.
+ * 6) Wait for any running NMIs to finish.
  *
  * If an NMI is executed, the first thing it does is to call
  * "ftrace_nmi_enter". This will check if the flag is set to write
@@ -95,9 +95,9 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
  * are the same as what exists.
  */
 
-#define MOD_CODE_WRITE_FLAG (1 << 31)	/* set when NMI should do the write */
 static atomic_t nmi_running = ATOMIC_INIT(0);
 static int mod_code_status;		/* holds return value of text write */
+static int mod_code_write;		/* set when NMI should do the write */
 static void *mod_code_ip;		/* holds the IP to write to */
 static void *mod_code_newcode;		/* holds the text to write to the IP */
 
@@ -114,20 +114,6 @@ int ftrace_arch_read_dyn_info(char *buf, int size)
 	return r;
 }
 
-static void clear_mod_flag(void)
-{
-	int old = atomic_read(&nmi_running);
-
-	for (;;) {
-		int new = old & ~MOD_CODE_WRITE_FLAG;
-
-		if (old == new)
-			break;
-
-		old = atomic_cmpxchg(&nmi_running, old, new);
-	}
-}
-
 static void ftrace_mod_code(void)
 {
 	/*
@@ -141,39 +127,27 @@ static void ftrace_mod_code(void)
 
 	/* if we fail, then kill any new writers */
 	if (mod_code_status)
-		clear_mod_flag();
+		mod_code_write = 0;
 }
 
 void ftrace_nmi_enter(void)
 {
-	if (atomic_inc_return(&nmi_running) & MOD_CODE_WRITE_FLAG) {
-		smp_rmb();
+	atomic_inc(&nmi_running);
+	/* Must have nmi_running seen before reading write flag */
+	smp_mb();
+	if (mod_code_write) {
 		ftrace_mod_code();
 		atomic_inc(&nmi_update_count);
 	}
-	/* Must have previous changes seen before executions */
-	smp_mb();
 }
 
 void ftrace_nmi_exit(void)
 {
 	/* Finish all executions before clearing nmi_running */
-	smp_mb();
+	smp_wmb();
 	atomic_dec(&nmi_running);
 }
 
-static void wait_for_nmi_and_set_mod_flag(void)
-{
-	if (!atomic_cmpxchg(&nmi_running, 0, MOD_CODE_WRITE_FLAG))
-		return;
-
-	do {
-		cpu_relax();
-	} while (atomic_cmpxchg(&nmi_running, 0, MOD_CODE_WRITE_FLAG));
-
-	nmi_wait_count++;
-}
-
 static void wait_for_nmi(void)
 {
 	if (!atomic_read(&nmi_running))
@@ -193,19 +167,28 @@ do_ftrace_mod_code(unsigned long ip, void *new_code)
 	mod_code_newcode = new_code;
 
 	/* The buffers need to be visible before we let NMIs write them */
+	smp_wmb();
+
+	mod_code_write = 1;
+
+	/* Make sure write bit is visible before we wait on NMIs */
 	smp_mb();
 
-	wait_for_nmi_and_set_mod_flag();
+	wait_for_nmi();
 
 	/* Make sure all running NMIs have finished before we write the code */
 	smp_mb();
 
 	ftrace_mod_code();
 
 	/* Make sure the write happens before clearing the bit */
+	smp_wmb();
+
+	mod_code_write = 0;
+
+	/* make sure NMIs see the cleared bit */
 	smp_mb();
 
-	clear_mod_flag();
 	wait_for_nmi();
 
 	return mod_code_status;

trunk/kernel/trace/Makefile

@@ -44,6 +44,5 @@ obj-$(CONFIG_EVENT_TRACER) += trace_events.o
 obj-$(CONFIG_EVENT_TRACER) += events.o
 obj-$(CONFIG_EVENT_TRACER) += trace_export.o
 obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
-obj-$(CONFIG_EVENT_PROFILE) += trace_event_profile.o
 
 libftrace-y := ftrace.o

trunk/kernel/trace/events.c

@@ -12,3 +12,4 @@
 #include "trace_events_stage_2.h"
 #include "trace_events_stage_3.h"
 
+#include <trace/trace_event_types.h>

trunk/kernel/trace/ring_buffer.c

@@ -535,8 +535,8 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
 extern int ring_buffer_page_too_big(void);
 
 #ifdef CONFIG_HOTPLUG_CPU
-static int __cpuinit rb_cpu_notify(struct notifier_block *self,
-				   unsigned long action, void *hcpu);
+static int rb_cpu_notify(struct notifier_block *self,
+			 unsigned long action, void *hcpu);
 #endif
 
 /**
@@ -2784,8 +2784,8 @@ static __init int rb_init_debugfs(void)
 fs_initcall(rb_init_debugfs);
 
 #ifdef CONFIG_HOTPLUG_CPU
-static int __cpuinit rb_cpu_notify(struct notifier_block *self,
-				   unsigned long action, void *hcpu)
+static int rb_cpu_notify(struct notifier_block *self,
+			 unsigned long action, void *hcpu)
 {
 	struct ring_buffer *buffer =
 		container_of(self, struct ring_buffer, cpu_notify);