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authorSteven Rostedt <rostedt@goodmis.org>2008-05-12 21:21:01 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 21:56:02 +0200
commit53d0aa773053ab18287781e25d52c5faf9e0e09e (patch)
treec0e268cb22a0416efca8709c677d41b513af04d3
parent72b59d67f80983f7bb587b086fb4cb1bc95263a4 (diff)
ftrace: add logic to record overruns
This patch sets up the infrastructure to record overruns of the tracing buffer. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--kernel/trace/trace.c16
-rw-r--r--kernel/trace/trace.h6
2 files changed, 16 insertions, 6 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1281969103b8..b9126ef46a9e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -609,6 +609,7 @@ void unregister_tracer(struct tracer *type)
void tracing_reset(struct trace_array_cpu *data)
{
data->trace_idx = 0;
+ data->overrun = 0;
data->trace_head = data->trace_tail = head_page(data);
data->trace_head_idx = 0;
data->trace_tail_idx = 0;
@@ -750,6 +751,7 @@ tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data)
if (data->trace_head == data->trace_tail &&
idx_next == data->trace_tail_idx) {
/* overrun */
+ data->overrun++;
data->trace_tail_idx++;
if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
data->trace_tail =
@@ -2353,8 +2355,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
{
struct trace_iterator *iter = filp->private_data;
struct trace_array_cpu *data;
- struct trace_array *tr = iter->tr;
- struct tracer *tracer = iter->trace;
static cpumask_t mask;
static int start;
unsigned long flags;
@@ -2433,10 +2433,11 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
if (cnt >= PAGE_SIZE)
cnt = PAGE_SIZE - 1;
- memset(iter, 0, sizeof(*iter));
- iter->tr = tr;
- iter->trace = tracer;
+ /* reset all but tr, trace, and overruns */
iter->pos = -1;
+ memset(&iter->seq, 0,
+ sizeof(struct trace_iterator) -
+ offsetof(struct trace_iterator, seq));
/*
* We need to stop all tracing on all CPUS to read the
@@ -2465,6 +2466,11 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
for_each_cpu_mask(cpu, mask) {
data = iter->tr->data[cpu];
__raw_spin_lock(&data->lock);
+
+ if (data->overrun > iter->last_overrun[cpu])
+ iter->overrun[cpu] +=
+ data->overrun - iter->last_overrun[cpu];
+ iter->last_overrun[cpu] = data->overrun;
}
while (find_next_entry_inc(iter) != NULL) {
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8991c5efcc74..c1ec134ac356 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -97,6 +97,7 @@ struct trace_array_cpu {
void *trace_head; /* producer */
void *trace_tail; /* consumer */
unsigned long trace_idx;
+ unsigned long overrun;
unsigned long saved_latency;
unsigned long critical_start;
unsigned long critical_end;
@@ -157,10 +158,13 @@ struct trace_seq {
* results to users and which routines might sleep, etc:
*/
struct trace_iterator {
- struct trace_seq seq;
struct trace_array *tr;
struct tracer *trace;
+ long last_overrun[NR_CPUS];
+ long overrun[NR_CPUS];
+ /* The below is zeroed out in pipe_read */
+ struct trace_seq seq;
struct trace_entry *ent;
int cpu;