tracing: Kill trace_cpu struct/members

After the previous changes trace_array_cpu->trace_cpu and
trace_array->trace_cpu becomes write-only. Remove these members
and kill "struct trace_cpu" as well.

As a side effect this also removes memset(per_cpu_memory, 0).
It was not needed, alloc_percpu() returns zero-filled memory.

Link: http://lkml.kernel.org/r/20130723152613.GA23741@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dd7780ddde083b86871f5ba0a333a0f09d6ccfcd..69cba470ea967815b2f03f2d65f33adcee743f54 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5865,17 +5865,6 @@ struct dentry *trace_instance_dir;
 static void
 init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer);
 
-static void init_trace_buffers(struct trace_array *tr, struct trace_buffer *buf)
-{
-       int cpu;
-
-       for_each_tracing_cpu(cpu) {
-               memset(per_cpu_ptr(buf->data, cpu), 0, sizeof(struct trace_array_cpu));
-               per_cpu_ptr(buf->data, cpu)->trace_cpu.cpu = cpu;
-               per_cpu_ptr(buf->data, cpu)->trace_cpu.tr = tr;
-       }
-}
-
 static int
 allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
 {
@@ -5893,8 +5882,6 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size
                return -ENOMEM;
        }
 
-       init_trace_buffers(tr, buf);
-
        /* Allocate the first page for all buffers */
        set_buffer_entries(&tr->trace_buffer,
                           ring_buffer_size(tr->trace_buffer.buffer, 0));
@@ -5961,10 +5948,6 @@ static int new_instance_create(const char *name)
        if (allocate_trace_buffers(tr, trace_buf_size) < 0)
                goto out_free_tr;
 
-       /* Holder for file callbacks */
-       tr->trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
-       tr->trace_cpu.tr = tr;
-
        tr->dir = debugfs_create_dir(name, trace_instance_dir);
        if (!tr->dir)
                goto out_free_tr;
@@ -6438,10 +6421,6 @@ __init static int tracer_alloc_buffers(void)
 
        global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
 
-       /* Holder for file callbacks */
-       global_trace.trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
-       global_trace.trace_cpu.tr = &global_trace;
-
        INIT_LIST_HEAD(&global_trace.systems);
        INIT_LIST_HEAD(&global_trace.events);
        list_add(&global_trace.list, &ftrace_trace_arrays);

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e7d643b8a907d6dbd027c723115b3d5a21dc9c9e..afaae41b0a0269012ae394dc5df877cd5cf86045 100644 (file)
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -130,19 +130,12 @@ enum trace_flag_type {
 
 struct trace_array;
 
-struct trace_cpu {
-       struct trace_array      *tr;
-       struct dentry           *dir;
-       int                     cpu;
-};
-
 /*
  * The CPU trace array - it consists of thousands of trace entries
  * plus some other descriptor data: (for example which task started
  * the trace, etc.)
  */
 struct trace_array_cpu {
-       struct trace_cpu        trace_cpu;
        atomic_t                disabled;
        void                    *buffer_page;   /* ring buffer spare */
 
@@ -196,7 +189,6 @@ struct trace_array {
        bool                    allocated_snapshot;
 #endif
        int                     buffer_disabled;
-       struct trace_cpu        trace_cpu;      /* place holder */
 #ifdef CONFIG_FTRACE_SYSCALLS
        int                     sys_refcount_enter;
        int                     sys_refcount_exit;