[PATCH v3 06/17] tracepoint: use new hashtable implementation

Sasha Levin
2012-08-22T02:27:34Z

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

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
kernel/tracepoint.c | 27 +++++++++++----------------
1 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index d96ba22..854df92 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -26,6 +26,7 @@
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/static_key.h>
+#include <linux/hashtable.h>

extern struct tracepoint * const __start___tracepoints_ptrs[];
extern struct tracepoint * const __stop___tracepoints_ptrs[];
@@ -49,8 +50,7 @@ static LIST_HEAD(tracepoint_module_list);
* Protected by tracepoints_mutex.
*/
#define TRACEPOINT_HASH_BITS 6
-#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
-static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
+static DEFINE_HASHTABLE(tracepoint_table, TRACEPOINT_HASH_BITS);

/*
* Note about RCU :
@@ -191,16 +191,15 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry,
*/
static struct tracepoint_entry *get_tracepoint(const char *name)
{
- struct hlist_head *head;
struct hlist_node *node;
struct tracepoint_entry *e;
u32 hash = jhash(name, strlen(name), 0);

- head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
- hlist_for_each_entry(e, node, head, hlist) {
+ hash_for_each_possible(tracepoint_table, e, node, hlist, hash) {
if (!strcmp(name, e->name))
return e;
}
+
return NULL;
}

@@ -210,19 +209,13 @@ static struct tracepoint_entry *get_tracepoint(const char *name)
*/
static struct tracepoint_entry *add_tracepoint(const char *name)
{
- struct hlist_head *head;
- struct hlist_node *node;
struct tracepoint_entry *e;
size_t name_len = strlen(name) + 1;
u32 hash = jhash(name, name_len-1, 0);

- head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
- hlist_for_each_entry(e, node, head, hlist) {
- if (!strcmp(name, e->name)) {
- printk(KERN_NOTICE
- "tracepoint %s busy\n", name);
- return ERR_PTR(-EEXIST); /* Already there */
- }
+ if (get_tracepoint(name)) {
+ printk(KERN_NOTICE "tracepoint %s busy\n", name);
+ return ERR_PTR(-EEXIST); /* Already there */
}
/*
* Using kmalloc here to allocate a variable length element. Could
@@ -234,7 +227,7 @@ static struct tracepoint_entry *add_tracepoint(const char *name)
memcpy(&e->name[0], name, name_len);
e->funcs = NULL;
e->refcount = 0;
- hlist_add_head(&e->hlist, head);
+ hash_add(tracepoint_table, &e->hlist, hash);
return e;
}

@@ -244,7 +237,7 @@ static struct tracepoint_entry *add_tracepoint(const char *name)
*/
static inline void remove_tracepoint(struct tracepoint_entry *e)
{
- hlist_del(&e->hlist);
+ hash_del(&e->hlist);
kfree(e);
}

@@ -722,6 +715,8 @@ struct notifier_block tracepoint_module_nb = {

static int init_tracepoints(void)
{
+ hash_init(tracepoint_table);
+
return register_module_notifier(&tracepoint_module_nb);
}
__initcall(init_tracepoints);
--
1.7.8.6