From d60da506cbeb3f1907a740547dd7ef04a93e908e Mon Sep 17 00:00:00 2001 From: Hiraku Toyooka Date: Wed, 17 Oct 2012 11:56:16 +0900 Subject: [PATCH] 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 Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 58 +++++++++++++++++++++++--------------------- 1 file 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) { -- GitLab