/*
* trace stack traces
*
+ * Copyright (C) 2004-2008, Soeren Sandmann
* Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
* Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
- * Copyright (C) 2004, 2005, Soeren Sandmann
*/
#include <linux/kallsyms.h>
#include <linux/debugfs.h>
#include <linux/irq.h>
#include <linux/fs.h>
+#include <asm/stacktrace.h>
+
#include "trace.h"
static struct trace_array *sysprof_trace;
static int __read_mostly tracer_enabled;
/*
- * 10 msecs for now:
+ * 1 msec sample interval by default:
*/
-static const unsigned long sample_period = 1000000;
+static unsigned long sample_period = 1000000;
+static const unsigned int sample_max_depth = 512;
+static DEFINE_MUTEX(sample_timer_lock);
/*
* Per CPU hrtimers that do the profiling:
*/
static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
{
+ int ret;
+
if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
return 0;
- if (__copy_from_user_inatomic(frame, frame_pointer, sizeof(*frame)))
- return 0;
+ ret = 1;
+ pagefault_disable();
+ if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
+ ret = 0;
+ pagefault_enable();
+
+ return ret;
+}
+
+struct backtrace_info {
+ struct trace_array_cpu *data;
+ struct trace_array *tr;
+ int pos;
+};
+
+static void
+backtrace_warning_symbol(void *data, char *msg, unsigned long symbol)
+{
+ /* Ignore warnings */
+}
- return 1;
+static void backtrace_warning(void *data, char *msg)
+{
+ /* Ignore warnings */
+}
+
+static int backtrace_stack(void *data, char *name)
+{
+ /* Don't bother with IRQ stacks for now */
+ return -1;
+}
+
+static void backtrace_address(void *data, unsigned long addr, int reliable)
+{
+ struct backtrace_info *info = data;
+
+ if (info->pos < sample_max_depth && reliable) {
+ __trace_special(info->tr, info->data, 1, addr, 0);
+
+ info->pos++;
+ }
}
-#define SYSPROF_MAX_ADDRESSES 512
+static const struct stacktrace_ops backtrace_ops = {
+ .warning = backtrace_warning,
+ .warning_symbol = backtrace_warning_symbol,
+ .stack = backtrace_stack,
+ .address = backtrace_address,
+ .walk_stack = print_context_stack,
+};
+
+static int
+trace_kernel(struct pt_regs *regs, struct trace_array *tr,
+ struct trace_array_cpu *data)
+{
+ struct backtrace_info info;
+ unsigned long bp;
+ char *stack;
+
+ info.tr = tr;
+ info.data = data;
+ info.pos = 1;
+
+ __trace_special(info.tr, info.data, 1, regs->ip, 0);
+
+ stack = ((char *)regs + sizeof(struct pt_regs));
+#ifdef CONFIG_FRAME_POINTER
+ bp = regs->bp;
+#else
+ bp = 0;
+#endif
+
+ dump_trace(NULL, regs, (void *)stack, bp, &backtrace_ops, &info);
+
+ return info.pos;
+}
static void timer_notify(struct pt_regs *regs, int cpu)
{
- const void __user *frame_pointer;
struct trace_array_cpu *data;
struct stack_frame frame;
struct trace_array *tr;
+ const void __user *fp;
int is_user;
int i;
if (is_user && current->state != TASK_RUNNING)
return;
- if (!is_user) {
- /* kernel */
- ftrace(tr, data, current->pid, 1, 0);
- return;
+ __trace_special(tr, data, 0, 0, current->pid);
- }
+ if (!is_user)
+ i = trace_kernel(regs, tr, data);
+ else
+ i = 0;
+
+ /*
+ * Trace user stack if we are not a kernel thread
+ */
+ if (current->mm && i < sample_max_depth) {
+ regs = (struct pt_regs *)current->thread.sp0 - 1;
+
+ fp = (void __user *)regs->bp;
- trace_special(tr, data, 0, current->pid, regs->ip);
+ __trace_special(tr, data, 2, regs->ip, 0);
- frame_pointer = (void __user *)regs->bp;
+ while (i < sample_max_depth) {
+ frame.next_fp = NULL;
+ frame.return_address = 0;
+ if (!copy_stack_frame(fp, &frame))
+ break;
+ if ((unsigned long)fp < regs->sp)
+ break;
- for (i = 0; i < SYSPROF_MAX_ADDRESSES; i++) {
- if (!copy_stack_frame(frame_pointer, &frame))
- break;
- if ((unsigned long)frame_pointer < regs->sp)
- break;
+ __trace_special(tr, data, 2, frame.return_address,
+ (unsigned long)fp);
+ fp = frame.next_fp;
+
+ i++;
+ }
- trace_special(tr, data, 1, frame.return_address,
- (unsigned long)frame_pointer);
- frame_pointer = frame.next_fp;
}
- trace_special(tr, data, 2, current->pid, i);
+ /*
+ * Special trace entry if we overflow the max depth:
+ */
+ if (i == sample_max_depth)
+ __trace_special(tr, data, -1, -1, -1);
- if (i == SYSPROF_MAX_ADDRESSES)
- trace_special(tr, data, -1, -1, -1);
+ __trace_special(tr, data, 3, current->pid, i);
}
static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
return HRTIMER_RESTART;
}
-static void start_stack_timer(int cpu)
+static void start_stack_timer(void *unused)
{
- struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
+ struct hrtimer *hrtimer = &__get_cpu_var(stack_trace_hrtimer);
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer->function = stack_trace_timer_fn;
- hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
- hrtimer_start(hrtimer, ns_to_ktime(sample_period), HRTIMER_MODE_REL);
+ hrtimer_start(hrtimer, ns_to_ktime(sample_period),
+ HRTIMER_MODE_REL_PINNED);
}
static void start_stack_timers(void)
{
- cpumask_t saved_mask = current->cpus_allowed;
- int cpu;
-
- for_each_online_cpu(cpu) {
- set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
- start_stack_timer(cpu);
- printk("started timer on cpu%d\n", cpu);
- }
- set_cpus_allowed_ptr(current, &saved_mask);
+ on_each_cpu(start_stack_timer, NULL, 1);
}
static void stop_stack_timer(int cpu)
struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
hrtimer_cancel(hrtimer);
- printk("cancelled timer on cpu%d\n", cpu);
}
static void stop_stack_timers(void)
stop_stack_timer(cpu);
}
-static notrace void stack_reset(struct trace_array *tr)
-{
- int cpu;
-
- tr->time_start = ftrace_now(tr->cpu);
-
- for_each_online_cpu(cpu)
- tracing_reset(tr->data[cpu]);
-}
-
-static notrace void start_stack_trace(struct trace_array *tr)
-{
- stack_reset(tr);
- start_stack_timers();
- tracer_enabled = 1;
-}
-
-static notrace void stop_stack_trace(struct trace_array *tr)
+static void stop_stack_trace(struct trace_array *tr)
{
+ mutex_lock(&sample_timer_lock);
stop_stack_timers();
tracer_enabled = 0;
+ mutex_unlock(&sample_timer_lock);
}
-static notrace void stack_trace_init(struct trace_array *tr)
+static int stack_trace_init(struct trace_array *tr)
{
sysprof_trace = tr;
- if (tr->ctrl)
- start_stack_trace(tr);
-}
+ tracing_start_cmdline_record();
-static notrace void stack_trace_reset(struct trace_array *tr)
-{
- if (tr->ctrl)
- stop_stack_trace(tr);
+ mutex_lock(&sample_timer_lock);
+ start_stack_timers();
+ tracer_enabled = 1;
+ mutex_unlock(&sample_timer_lock);
+ return 0;
}
-static void stack_trace_ctrl_update(struct trace_array *tr)
+static void stack_trace_reset(struct trace_array *tr)
{
- /* When starting a new trace, reset the buffers */
- if (tr->ctrl)
- start_stack_trace(tr);
- else
- stop_stack_trace(tr);
+ tracing_stop_cmdline_record();
+ stop_stack_trace(tr);
}
static struct tracer stack_trace __read_mostly =
.name = "sysprof",
.init = stack_trace_init,
.reset = stack_trace_reset,
- .ctrl_update = stack_trace_ctrl_update,
#ifdef CONFIG_FTRACE_SELFTEST
- .selftest = trace_selftest_startup_stack,
+ .selftest = trace_selftest_startup_sysprof,
#endif
};
return register_tracer(&stack_trace);
}
device_initcall(init_stack_trace);
+
+#define MAX_LONG_DIGITS 22
+
+static ssize_t
+sysprof_sample_read(struct file *filp, char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ char buf[MAX_LONG_DIGITS];
+ int r;
+
+ r = sprintf(buf, "%ld\n", nsecs_to_usecs(sample_period));
+
+ return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+sysprof_sample_write(struct file *filp, const char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ char buf[MAX_LONG_DIGITS];
+ unsigned long val;
+
+ if (cnt > MAX_LONG_DIGITS-1)
+ cnt = MAX_LONG_DIGITS-1;
+
+ if (copy_from_user(&buf, ubuf, cnt))
+ return -EFAULT;
+
+ buf[cnt] = 0;
+
+ val = simple_strtoul(buf, NULL, 10);
+ /*
+ * Enforce a minimum sample period of 100 usecs:
+ */
+ if (val < 100)
+ val = 100;
+
+ mutex_lock(&sample_timer_lock);
+ stop_stack_timers();
+ sample_period = val * 1000;
+ start_stack_timers();
+ mutex_unlock(&sample_timer_lock);
+
+ return cnt;
+}
+
+static const struct file_operations sysprof_sample_fops = {
+ .read = sysprof_sample_read,
+ .write = sysprof_sample_write,
+};
+
+void init_tracer_sysprof_debugfs(struct dentry *d_tracer)
+{
+
+ trace_create_file("sysprof_sample_period", 0644,
+ d_tracer, NULL, &sysprof_sample_fops);
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff