[PATCH v7 16/16] tracing output: use new hashtable implementation

Sasha Levin
2012-10-28T19:04:23Z

Switch tracing to use the new hashtable implementation. This reduces the amount of
generic unrelated code in the tracing module.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
kernel/trace/trace_output.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 123b189..1324c1a 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -8,15 +8,15 @@
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>
+#include <linux/hashtable.h>

#include "trace_output.h"

-/* must be a power of 2 */
-#define EVENT_HASHSIZE 128
+#define EVENT_HASH_BITS 7

DECLARE_RWSEM(trace_event_mutex);

-static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
+static DEFINE_HASHTABLE(event_hash, EVENT_HASH_BITS);

static int next_event_type = __TRACE_LAST_TYPE + 1;

@@ -712,11 +712,8 @@ struct trace_event *ftrace_find_event(int type)
{
struct trace_event *event;
struct hlist_node *n;
- unsigned key;

- key = type & (EVENT_HASHSIZE - 1);
-
- hlist_for_each_entry(event, n, &event_hash[key], node) {
+ hash_for_each_possible(event_hash, event, n, node, type) {
if (event->type == type)
return event;
}
@@ -781,7 +778,6 @@ void trace_event_read_unlock(void)
*/
int register_ftrace_event(struct trace_event *event)
{
- unsigned key;
int ret = 0;

down_write(&trace_event_mutex);
@@ -833,9 +829,7 @@ int register_ftrace_event(struct trace_event *event)
if (event->funcs->binary == NULL)
event->funcs->binary = trace_nop_print;

- key = event->type & (EVENT_HASHSIZE - 1);
-
- hlist_add_head(&event->node, &event_hash[key]);
+ hash_add(event_hash, &event->node, event->type);

ret = event->type;
out:
@@ -850,7 +844,7 @@ EXPORT_SYMBOL_GPL(register_ftrace_event);
*/
int __unregister_ftrace_event(struct trace_event *event)
{
- hlist_del(&event->node);
+ hash_del(&event->node);
list_del(&event->list);
return 0;
}
@@ -1323,6 +1317,8 @@ __init static int init_events(void)
}
}

+ hash_init(event_hash);
+
return 0;
}
early_initcall(init_events);
--
1.7.12.4