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authorHiraku Toyooka <hiraku.toyooka.gu@hitachi.com>2012-10-17 11:56:16 +0900
committerSteven Rostedt <rostedt@goodmis.org>2012-11-15 17:10:21 -0500
commitd60da506cbeb3f1907a740547dd7ef04a93e908e (patch)
treeb9d32b5ac2061c2c86f0e9d074349f70d8d52199 /kernel
parent1c7d66732458dc187008e3f5b2f71e019e320fc2 (diff)
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tracing: Add a resize function to make one buffer equivalent to another buffer
Trace buffer size is now per-cpu, so that there are the following two patterns in resizing of buffers. (1) resize per-cpu buffers to same given size (2) resize per-cpu buffers to another trace_array's buffer size for each CPU (such as preparing the max_tr which is equivalent to the global_trace's size) __tracing_resize_ring_buffer() can be used for (1), and had implemented (2) inside it for resetting the global_trace to the original size. (2) was also implemented in another place. So this patch assembles them in a new function - resize_buffer_duplicate_size(). Link: http://lkml.kernel.org/r/20121017025616.2627.91226.stgit@falsita Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c58
1 files changed, 31 insertions, 27 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b69cc380322d..64ad9bc4275b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3034,6 +3034,31 @@ static void set_buffer_entries(struct trace_array *tr, unsigned long val)
tr->data[cpu]->entries = val;
}
+/* resize @tr's buffer to the size of @size_tr's entries */
+static int resize_buffer_duplicate_size(struct trace_array *tr,
+ struct trace_array *size_tr, int cpu_id)
+{
+ int cpu, ret = 0;
+
+ if (cpu_id == RING_BUFFER_ALL_CPUS) {
+ for_each_tracing_cpu(cpu) {
+ ret = ring_buffer_resize(tr->buffer,
+ size_tr->data[cpu]->entries, cpu);
+ if (ret < 0)
+ break;
+ tr->data[cpu]->entries = size_tr->data[cpu]->entries;
+ }
+ } else {
+ ret = ring_buffer_resize(tr->buffer,
+ size_tr->data[cpu_id]->entries, cpu_id);
+ if (ret == 0)
+ tr->data[cpu_id]->entries =
+ size_tr->data[cpu_id]->entries;
+ }
+
+ return ret;
+}
+
static int __tracing_resize_ring_buffer(unsigned long size, int cpu)
{
int ret;
@@ -3058,23 +3083,8 @@ static int __tracing_resize_ring_buffer(unsigned long size, int cpu)
ret = ring_buffer_resize(max_tr.buffer, size, cpu);
if (ret < 0) {
- int r = 0;
-
- if (cpu == RING_BUFFER_ALL_CPUS) {
- int i;
- for_each_tracing_cpu(i) {
- r = ring_buffer_resize(global_trace.buffer,
- global_trace.data[i]->entries,
- i);
- if (r < 0)
- break;
- }
- } else {
- r = ring_buffer_resize(global_trace.buffer,
- global_trace.data[cpu]->entries,
- cpu);
- }
-
+ int r = resize_buffer_duplicate_size(&global_trace,
+ &global_trace, cpu);
if (r < 0) {
/*
* AARGH! We are left with different
@@ -3212,17 +3222,11 @@ static int tracing_set_tracer(const char *buf)
topts = create_trace_option_files(t);
if (t->use_max_tr) {
- int cpu;
/* we need to make per cpu buffer sizes equivalent */
- for_each_tracing_cpu(cpu) {
- ret = ring_buffer_resize(max_tr.buffer,
- global_trace.data[cpu]->entries,
- cpu);
- if (ret < 0)
- goto out;
- max_tr.data[cpu]->entries =
- global_trace.data[cpu]->entries;
- }
+ ret = resize_buffer_duplicate_size(&max_tr, &global_trace,
+ RING_BUFFER_ALL_CPUS);
+ if (ret < 0)
+ goto out;
}
if (t->init) {