#include <linux/poll.h>
#include <linux/nmi.h>
#include <linux/fs.h>
+#include <linux/sched/rt.h>
#include "trace.h"
#include "trace_output.h"
static struct tracer *trace_types __read_mostly;
/* current_trace points to the tracer that is currently active */
-static struct tracer *current_trace __read_mostly;
+static struct tracer *current_trace __read_mostly = &nop_trace;
/*
* trace_types_lock is used to protect the trace_types list.
return;
WARN_ON_ONCE(!irqs_disabled());
- if (!current_trace->use_max_tr) {
- WARN_ON_ONCE(1);
+
+ if (!current_trace->allocated_snapshot) {
+ /* Only the nop tracer should hit this when disabling */
+ WARN_ON_ONCE(current_trace != &nop_trace);
return;
}
+
arch_spin_lock(&ftrace_max_lock);
tr->buffer = max_tr.buffer;
return;
WARN_ON_ONCE(!irqs_disabled());
- if (!current_trace->use_max_tr) {
- WARN_ON_ONCE(1);
+ if (WARN_ON_ONCE(!current_trace->allocated_snapshot))
return;
- }
arch_spin_lock(&ftrace_max_lock);
current_trace = type;
- /* If we expanded the buffers, make sure the max is expanded too */
- if (ring_buffer_expanded && type->use_max_tr)
- ring_buffer_resize(max_tr.buffer, trace_buf_size,
- RING_BUFFER_ALL_CPUS);
+ if (type->use_max_tr) {
+ /* If we expanded the buffers, make sure the max is expanded too */
+ if (ring_buffer_expanded)
+ ring_buffer_resize(max_tr.buffer, trace_buf_size,
+ RING_BUFFER_ALL_CPUS);
+ type->allocated_snapshot = true;
+ }
/* the test is responsible for initializing and enabling */
pr_info("Testing tracer %s: ", type->name);
/* Only reset on passing, to avoid touching corrupted buffers */
tracing_reset_online_cpus(tr);
- /* Shrink the max buffer again */
- if (ring_buffer_expanded && type->use_max_tr)
- ring_buffer_resize(max_tr.buffer, 1,
- RING_BUFFER_ALL_CPUS);
+ if (type->use_max_tr) {
+ type->allocated_snapshot = false;
+
+ /* Shrink the max buffer again */
+ if (ring_buffer_expanded)
+ ring_buffer_resize(max_tr.buffer, 1,
+ RING_BUFFER_ALL_CPUS);
+ }
printk(KERN_CONT "PASSED\n");
}
{
struct ring_buffer *buffer = tr->buffer;
+ if (!buffer)
+ return;
+
ring_buffer_record_disable(buffer);
/* Make sure all commits have finished */
struct ring_buffer *buffer = tr->buffer;
int cpu;
+ if (!buffer)
+ return;
+
ring_buffer_record_disable(buffer);
/* Make sure all commits have finished */
entry->preempt_count = pc & 0xff;
entry->pid = (tsk) ? tsk->pid : 0;
- entry->padding = 0;
entry->flags =
#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
*/
preempt_disable_notrace();
- use_stack = ++__get_cpu_var(ftrace_stack_reserve);
+ use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
/*
* We don't need any atomic variables, just a barrier.
* If an interrupt comes in, we don't care, because it would
out:
/* Again, don't let gcc optimize things here */
barrier();
- __get_cpu_var(ftrace_stack_reserve)--;
+ __this_cpu_dec(ftrace_stack_reserve);
preempt_enable_notrace();
}
static char *get_trace_buf(void)
{
struct trace_buffer_struct *percpu_buffer;
- struct trace_buffer_struct *buffer;
/*
* If we have allocated per cpu buffers, then we do not
if (!percpu_buffer)
return NULL;
- buffer = per_cpu_ptr(percpu_buffer, smp_processor_id());
-
- return buffer->buffer;
+ return this_cpu_ptr(&percpu_buffer->buffer[0]);
}
static int alloc_percpu_trace_buffer(void)
static void *s_start(struct seq_file *m, loff_t *pos)
{
struct trace_iterator *iter = m->private;
- static struct tracer *old_tracer;
int cpu_file = iter->cpu_file;
void *p = NULL;
loff_t l = 0;
int cpu;
- /* copy the tracer to avoid using a global lock all around */
+ /*
+ * copy the tracer to avoid using a global lock all around.
+ * iter->trace is a copy of current_trace, the pointer to the
+ * name may be used instead of a strcmp(), as iter->trace->name
+ * will point to the same string as current_trace->name.
+ */
mutex_lock(&trace_types_lock);
- if (unlikely(old_tracer != current_trace && current_trace)) {
- old_tracer = current_trace;
+ if (unlikely(current_trace && iter->trace->name != current_trace->name))
*iter->trace = *current_trace;
- }
mutex_unlock(&trace_types_lock);
- atomic_inc(&trace_record_cmdline_disabled);
+ if (iter->snapshot && iter->trace->use_max_tr)
+ return ERR_PTR(-EBUSY);
+
+ if (!iter->snapshot)
+ atomic_inc(&trace_record_cmdline_disabled);
if (*pos != iter->pos) {
iter->ent = NULL;
{
struct trace_iterator *iter = m->private;
- atomic_dec(&trace_record_cmdline_disabled);
+ if (iter->snapshot && iter->trace->use_max_tr)
+ return;
+
+ if (!iter->snapshot)
+ atomic_dec(&trace_record_cmdline_disabled);
trace_access_unlock(iter->cpu_file);
trace_event_read_unlock();
}
unsigned long total;
const char *name = "preemption";
- if (type)
- name = type->name;
+ name = type->name;
get_total_entries(tr, &total, &entries);
seq_printf(m, "# MAY BE MISSING FUNCTION EVENTS\n");
}
+#ifdef CONFIG_TRACER_MAX_TRACE
+static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
+{
+ if (iter->trace->allocated_snapshot)
+ seq_printf(m, "#\n# * Snapshot is allocated *\n#\n");
+ else
+ seq_printf(m, "#\n# * Snapshot is freed *\n#\n");
+
+ seq_printf(m, "# Snapshot commands:\n");
+ seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
+ seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
+ seq_printf(m, "# Takes a snapshot of the main buffer.\n");
+ seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
+ seq_printf(m, "# (Doesn't have to be '2' works with any number that\n");
+ seq_printf(m, "# is not a '0' or '1')\n");
+}
+#else
+/* Should never be called */
+static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
+#endif
+
static int s_show(struct seq_file *m, void *v)
{
struct trace_iterator *iter = v;
seq_puts(m, "#\n");
test_ftrace_alive(m);
}
- if (iter->trace && iter->trace->print_header)
+ if (iter->snapshot && trace_empty(iter))
+ print_snapshot_help(m, iter);
+ else if (iter->trace && iter->trace->print_header)
iter->trace->print_header(m);
else
trace_default_header(m);
};
static struct trace_iterator *
-__tracing_open(struct inode *inode, struct file *file)
+__tracing_open(struct inode *inode, struct file *file, bool snapshot)
{
long cpu_file = (long) inode->i_private;
struct trace_iterator *iter;
if (!iter->trace)
goto fail;
- if (current_trace)
- *iter->trace = *current_trace;
+ *iter->trace = *current_trace;
if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
goto fail;
- if (current_trace && current_trace->print_max)
+ if (current_trace->print_max || snapshot)
iter->tr = &max_tr;
else
iter->tr = &global_trace;
+ iter->snapshot = snapshot;
iter->pos = -1;
mutex_init(&iter->mutex);
iter->cpu_file = cpu_file;
if (trace_clocks[trace_clock_id].in_ns)
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
- /* stop the trace while dumping */
- tracing_stop();
+ /* stop the trace while dumping if we are not opening "snapshot" */
+ if (!iter->snapshot)
+ tracing_stop();
if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
for_each_tracing_cpu(cpu) {
if (iter->trace && iter->trace->close)
iter->trace->close(iter);
- /* reenable tracing if it was previously enabled */
- tracing_start();
+ if (!iter->snapshot)
+ /* reenable tracing if it was previously enabled */
+ tracing_start();
mutex_unlock(&trace_types_lock);
mutex_destroy(&iter->mutex);
}
if (file->f_mode & FMODE_READ) {
- iter = __tracing_open(inode, file);
+ iter = __tracing_open(inode, file, false);
if (IS_ERR(iter))
ret = PTR_ERR(iter);
else if (trace_flags & TRACE_ITER_LATENCY_FMT)
int r;
mutex_lock(&trace_types_lock);
- if (current_trace)
- r = sprintf(buf, "%s\n", current_trace->name);
- else
- r = sprintf(buf, "\n");
+ r = sprintf(buf, "%s\n", current_trace->name);
mutex_unlock(&trace_types_lock);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
static struct trace_option_dentry *topts;
struct trace_array *tr = &global_trace;
struct tracer *t;
+ bool had_max_tr;
int ret = 0;
mutex_lock(&trace_types_lock);
goto out;
trace_branch_disable();
- if (current_trace && current_trace->reset)
+ if (current_trace->reset)
current_trace->reset(tr);
- if (current_trace && current_trace->use_max_tr) {
+
+ had_max_tr = current_trace->allocated_snapshot;
+ current_trace = &nop_trace;
+
+ if (had_max_tr && !t->use_max_tr) {
+ /*
+ * We need to make sure that the update_max_tr sees that
+ * current_trace changed to nop_trace to keep it from
+ * swapping the buffers after we resize it.
+ * The update_max_tr is called from interrupts disabled
+ * so a synchronized_sched() is sufficient.
+ */
+ synchronize_sched();
/*
* We don't free the ring buffer. instead, resize it because
* The max_tr ring buffer has some state (e.g. ring->clock) and
*/
ring_buffer_resize(max_tr.buffer, 1, RING_BUFFER_ALL_CPUS);
set_buffer_entries(&max_tr, 1);
+ tracing_reset_online_cpus(&max_tr);
+ current_trace->allocated_snapshot = false;
}
destroy_trace_option_files(topts);
- current_trace = &nop_trace;
-
topts = create_trace_option_files(t);
- if (t->use_max_tr) {
+ if (t->use_max_tr && !had_max_tr) {
/* we need to make per cpu buffer sizes equivalent */
ret = resize_buffer_duplicate_size(&max_tr, &global_trace,
RING_BUFFER_ALL_CPUS);
if (ret < 0)
goto out;
+ t->allocated_snapshot = true;
}
if (t->init) {
ret = -ENOMEM;
goto fail;
}
- if (current_trace)
- *iter->trace = *current_trace;
+ *iter->trace = *current_trace;
if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
ret = -ENOMEM;
size_t cnt, loff_t *ppos)
{
struct trace_iterator *iter = filp->private_data;
- static struct tracer *old_tracer;
ssize_t sret;
/* return any leftover data */
/* copy the tracer to avoid using a global lock all around */
mutex_lock(&trace_types_lock);
- if (unlikely(old_tracer != current_trace && current_trace)) {
- old_tracer = current_trace;
+ if (unlikely(iter->trace->name != current_trace->name))
*iter->trace = *current_trace;
- }
mutex_unlock(&trace_types_lock);
/*
.ops = &tracing_pipe_buf_ops,
.spd_release = tracing_spd_release_pipe,
};
- static struct tracer *old_tracer;
ssize_t ret;
size_t rem;
unsigned int i;
/* copy the tracer to avoid using a global lock all around */
mutex_lock(&trace_types_lock);
- if (unlikely(old_tracer != current_trace && current_trace)) {
- old_tracer = current_trace;
+ if (unlikely(iter->trace->name != current_trace->name))
*iter->trace = *current_trace;
- }
mutex_unlock(&trace_types_lock);
mutex_lock(&iter->mutex);
* Reset the buffer so that it doesn't have incomparable timestamps.
*/
tracing_reset_online_cpus(&global_trace);
- if (max_tr.buffer)
- tracing_reset_online_cpus(&max_tr);
+ tracing_reset_online_cpus(&max_tr);
mutex_unlock(&trace_types_lock);
return single_open(file, tracing_clock_show, NULL);
}
+#ifdef CONFIG_TRACER_SNAPSHOT
+static int tracing_snapshot_open(struct inode *inode, struct file *file)
+{
+ struct trace_iterator *iter;
+ int ret = 0;
+
+ if (file->f_mode & FMODE_READ) {
+ iter = __tracing_open(inode, file, true);
+ if (IS_ERR(iter))
+ ret = PTR_ERR(iter);
+ }
+ return ret;
+}
+
+static ssize_t
+tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
+ loff_t *ppos)
+{
+ unsigned long val;
+ int ret;
+
+ ret = tracing_update_buffers();
+ if (ret < 0)
+ return ret;
+
+ ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+ if (ret)
+ return ret;
+
+ mutex_lock(&trace_types_lock);
+
+ if (current_trace->use_max_tr) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ switch (val) {
+ case 0:
+ if (current_trace->allocated_snapshot) {
+ /* free spare buffer */
+ ring_buffer_resize(max_tr.buffer, 1,
+ RING_BUFFER_ALL_CPUS);
+ set_buffer_entries(&max_tr, 1);
+ tracing_reset_online_cpus(&max_tr);
+ current_trace->allocated_snapshot = false;
+ }
+ break;
+ case 1:
+ if (!current_trace->allocated_snapshot) {
+ /* allocate spare buffer */
+ ret = resize_buffer_duplicate_size(&max_tr,
+ &global_trace, RING_BUFFER_ALL_CPUS);
+ if (ret < 0)
+ break;
+ current_trace->allocated_snapshot = true;
+ }
+
+ local_irq_disable();
+ /* Now, we're going to swap */
+ update_max_tr(&global_trace, current, smp_processor_id());
+ local_irq_enable();
+ break;
+ default:
+ if (current_trace->allocated_snapshot)
+ tracing_reset_online_cpus(&max_tr);
+ break;
+ }
+
+ if (ret >= 0) {
+ *ppos += cnt;
+ ret = cnt;
+ }
+out:
+ mutex_unlock(&trace_types_lock);
+ return ret;
+}
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+
static const struct file_operations tracing_max_lat_fops = {
.open = tracing_open_generic,
.read = tracing_max_lat_read,
.write = tracing_clock_write,
};
+#ifdef CONFIG_TRACER_SNAPSHOT
+static const struct file_operations snapshot_fops = {
+ .open = tracing_snapshot_open,
+ .read = seq_read,
+ .write = tracing_snapshot_write,
+ .llseek = tracing_seek,
+ .release = tracing_release,
+};
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
struct ftrace_buffer_info {
struct trace_array *tr;
void *spare;
cnt = ring_buffer_dropped_events_cpu(tr->buffer, cpu);
trace_seq_printf(s, "dropped events: %ld\n", cnt);
+ cnt = ring_buffer_read_events_cpu(tr->buffer, cpu);
+ trace_seq_printf(s, "read events: %ld\n", cnt);
+
count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
kfree(s);
static struct dentry *d_percpu;
-struct dentry *tracing_dentry_percpu(void)
+static struct dentry *tracing_dentry_percpu(void)
{
static int once;
struct dentry *d_tracer;
&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+ trace_create_file("snapshot", 0644, d_tracer,
+ (void *) TRACE_PIPE_ALL_CPU, &snapshot_fops);
+#endif
+
create_trace_options_dir();
for_each_tracing_cpu(cpu)
if (disable_tracing)
ftrace_kill();
+ /* Simulate the iterator */
trace_init_global_iter(&iter);
for_each_tracing_cpu(cpu) {
/* don't look at user memory in panic mode */
trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
- /* Simulate the iterator */
- iter.tr = &global_trace;
- iter.trace = current_trace;
-
switch (oops_dump_mode) {
case DUMP_ALL:
iter.cpu_file = TRACE_PIPE_ALL_CPU;
init_irq_work(&trace_work_wakeup, trace_wake_up);
register_tracer(&nop_trace);
- current_trace = &nop_trace;
+
/* All seems OK, enable tracing */
tracing_disabled = 0;
git.samba.org / sfrench / cifs-2.6.git / blobdiff