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SubjectRe: [PATCH v8 06/16] tracepoint: use new hashtable implementation
* Sasha Levin (levinsasha928@gmail.com) wrote:
> 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>

Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

> ---
> kernel/tracepoint.c | 25 +++++++++----------------
> 1 file changed, 9 insertions(+), 16 deletions(-)
>
> diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
> index d96ba22..5b599f1 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);
> }
>
> --
> 1.7.12.4
>

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com


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