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tracing: Add alloc/free_snapshot() to replace duplicate code 

Add alloc_snapshot() and free_snapshot() to allocate and free the
snapshot buffer respectively, and use these to remove duplicate
code.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2013-03-12 11:17:54 -04:00 committed by Steven Rostedt
parent e1df4cb682
commit 3209cff449
1 changed files with 42 additions and 37 deletions
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79
kernel/trace/trace.c
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@ -149,14 +149,14 @@ static int __init set_ftrace_dump_on_oops(char *str)
}
__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
static int __init alloc_snapshot(char *str)
static int __init boot_alloc_snapshot(char *str)
{
allocate_snapshot = true;
/* We also need the main ring buffer expanded */
ring_buffer_expanded = true;
return 1;
}
__setup("alloc_snapshot", alloc_snapshot);
__setup("alloc_snapshot", boot_alloc_snapshot);
static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
@ -470,6 +470,38 @@ EXPORT_SYMBOL_GPL(tracing_snapshot);
static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
struct trace_buffer *size_buf, int cpu_id);
static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
static int alloc_snapshot(struct trace_array *tr)
{
int ret;
if (!tr->allocated_snapshot) {
/* allocate spare buffer */
ret = resize_buffer_duplicate_size(&tr->max_buffer,
&tr->trace_buffer, RING_BUFFER_ALL_CPUS);
if (ret < 0)
return ret;
tr->allocated_snapshot = true;
}
return 0;
}
void free_snapshot(struct trace_array *tr)
{
/*
* We don't free the ring buffer. instead, resize it because
* The max_tr ring buffer has some state (e.g. ring->clock) and
* we want preserve it.
*/
ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
set_buffer_entries(&tr->max_buffer, 1);
tracing_reset_online_cpus(&tr->max_buffer);
tr->allocated_snapshot = false;
}
/**
* trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
@ -487,16 +519,9 @@ void tracing_snapshot_alloc(void)
struct trace_array *tr = &global_trace;
int ret;
if (!tr->allocated_snapshot) {
/* allocate spare buffer */
ret = resize_buffer_duplicate_size(&tr->max_buffer,
&tr->trace_buffer, RING_BUFFER_ALL_CPUS);
if (WARN_ON(ret < 0))
return;
tr->allocated_snapshot = true;
}
ret = alloc_snapshot(tr);
if (WARN_ON(ret < 0))
return;
tracing_snapshot();
}
@ -3581,15 +3606,7 @@ static int tracing_set_tracer(const char *buf)
* 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
* we want preserve it.
*/
ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
set_buffer_entries(&tr->max_buffer, 1);
tracing_reset_online_cpus(&tr->max_buffer);
tr->allocated_snapshot = false;
free_snapshot(tr);
}
#endif
destroy_trace_option_files(topts);
@ -3598,12 +3615,9 @@ static int tracing_set_tracer(const char *buf)
#ifdef CONFIG_TRACER_MAX_TRACE
if (t->use_max_tr && !had_max_tr) {
/* we need to make per cpu buffer sizes equivalent */
ret = resize_buffer_duplicate_size(&tr->max_buffer, &tr->trace_buffer,
RING_BUFFER_ALL_CPUS);
ret = alloc_snapshot(tr);
if (ret < 0)
goto out;
tr->allocated_snapshot = true;
}
#endif
@ -4475,14 +4489,8 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
ret = -EINVAL;
break;
}
if (tr->allocated_snapshot) {
/* free spare buffer */
ring_buffer_resize(tr->max_buffer.buffer, 1,
RING_BUFFER_ALL_CPUS);
set_buffer_entries(&tr->max_buffer, 1);
tracing_reset_online_cpus(&tr->max_buffer);
tr->allocated_snapshot = false;
}
if (tr->allocated_snapshot)
free_snapshot(tr);
break;
case 1:
/* Only allow per-cpu swap if the ring buffer supports it */
@ -4493,12 +4501,9 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
}
#endif
if (!tr->allocated_snapshot) {
/* allocate spare buffer */
ret = resize_buffer_duplicate_size(&tr->max_buffer,
&tr->trace_buffer, RING_BUFFER_ALL_CPUS);
ret = alloc_snapshot(tr);
if (ret < 0)
break;
tr->allocated_snapshot = true;
}
local_irq_disable();
/* Now, we're going to swap */