mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
* [PATCH] tracing: Use hashtable.h for event_hash
@ 2025-03-19 19:05 Sasha Levin
  0 siblings, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2025-03-19 19:05 UTC (permalink / raw)
  To: rostedt, mhiramat, mathieu.desnoyers
  Cc: linux-kernel, linux-trace-kernel, Sasha Levin

Convert the event_hash array in trace_output.c to use the generic
hashtable implementation from hashtable.h instead of the manually
implemented hash table.

This simplifies the code and makes it more maintainable by using the
standard hashtable API defined in hashtable.h.

Rename EVENT_HASHSIZE to EVENT_HASH_BITS to properly reflect its new
meaning as the number of bits for the hashtable size.

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/trace_output.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 03d56f711ad14..3144d020e6c6f 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -12,15 +12,16 @@
 #include <linux/sched/clock.h>
 #include <linux/sched/mm.h>
 #include <linux/idr.h>
+#include <linux/hashtable.h>
 
 #include "trace_output.h"
 
-/* must be a power of 2 */
-#define EVENT_HASHSIZE	128
+/* 2^7 = 128 */
+#define EVENT_HASH_BITS 7
 
 DECLARE_RWSEM(trace_event_sem);
 
-static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
+static DEFINE_HASHTABLE(event_hash, EVENT_HASH_BITS);
 
 enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
 {
@@ -694,11 +695,8 @@ int trace_print_lat_context(struct trace_iterator *iter)
 struct trace_event *ftrace_find_event(int type)
 {
 	struct trace_event *event;
-	unsigned key;
 
-	key = type & (EVENT_HASHSIZE - 1);
-
-	hlist_for_each_entry(event, &event_hash[key], node) {
+	hash_for_each_possible(event_hash, event, node, type) {
 		if (event->type == type)
 			return event;
 	}
@@ -753,7 +751,6 @@ void trace_event_read_unlock(void)
  */
 int register_trace_event(struct trace_event *event)
 {
-	unsigned key;
 	int ret = 0;
 
 	down_write(&trace_event_sem);
@@ -786,9 +783,7 @@ int register_trace_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:
@@ -803,7 +798,7 @@ EXPORT_SYMBOL_GPL(register_trace_event);
  */
 int __unregister_trace_event(struct trace_event *event)
 {
-	hlist_del(&event->node);
+	hash_del(&event->node);
 	free_trace_event_type(event->type);
 	return 0;
 }
-- 
2.39.5


^ permalink raw reply	[flat|nested] 2+ messages in thread
* Re: [for-next][PATCH 05/10] tracing: Use hashtable.h for event_hash
@ 2025-03-23 12:39 Steven Rostedt
  2025-03-23 13:28 ` [PATCH] " Sasha Levin
  0 siblings, 1 reply; 2+ messages in thread
From: Steven Rostedt @ 2025-03-23 12:39 UTC (permalink / raw)
  To: linux-kernel
  Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
	Sasha Levin


When I ran my scripts to merge all my topic branches, this one has a
slight conflict with the ftrace branch that adds function arguments to
the function and function graph tracer. As this is mostly a clean up,
I'm going to remove this patch and save it for the next merge window.

Sasha, could you just rebase this on my for-next branch for the repo in
the MAINTAINERS file?

-- Steve


On Sun, 23 Mar 2025 08:29:38 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: Sasha Levin <sashal@kernel.org>
> 
> Convert the event_hash array in trace_output.c to use the generic
> hashtable implementation from hashtable.h instead of the manually
> implemented hash table.
> 
> This simplifies the code and makes it more maintainable by using the
> standard hashtable API defined in hashtable.h.
> 
> Rename EVENT_HASHSIZE to EVENT_HASH_BITS to properly reflect its new
> meaning as the number of bits for the hashtable size.
> 
> Link: https://lore.kernel.org/20250319190545.3058319-1-sashal@kernel.org
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>  kernel/trace/trace_output.c | 19 +++++++------------
>  1 file changed, 7 insertions(+), 12 deletions(-)
> 
> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> index 03d56f711ad1..3144d020e6c6 100644
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
> @@ -12,15 +12,16 @@
>  #include <linux/sched/clock.h>
>  #include <linux/sched/mm.h>
>  #include <linux/idr.h>
> +#include <linux/hashtable.h>
>  
>  #include "trace_output.h"
>  
> -/* must be a power of 2 */
> -#define EVENT_HASHSIZE	128
> +/* 2^7 = 128 */
> +#define EVENT_HASH_BITS 7
>  
>  DECLARE_RWSEM(trace_event_sem);
>  
> -static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
> +static DEFINE_HASHTABLE(event_hash, EVENT_HASH_BITS);
>  
>  enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
>  {
> @@ -694,11 +695,8 @@ int trace_print_lat_context(struct trace_iterator *iter)
>  struct trace_event *ftrace_find_event(int type)
>  {
>  	struct trace_event *event;
> -	unsigned key;
>  
> -	key = type & (EVENT_HASHSIZE - 1);
> -
> -	hlist_for_each_entry(event, &event_hash[key], node) {
> +	hash_for_each_possible(event_hash, event, node, type) {
>  		if (event->type == type)
>  			return event;
>  	}
> @@ -753,7 +751,6 @@ void trace_event_read_unlock(void)
>   */
>  int register_trace_event(struct trace_event *event)
>  {
> -	unsigned key;
>  	int ret = 0;
>  
>  	down_write(&trace_event_sem);
> @@ -786,9 +783,7 @@ int register_trace_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:
> @@ -803,7 +798,7 @@ EXPORT_SYMBOL_GPL(register_trace_event);
>   */
>  int __unregister_trace_event(struct trace_event *event)
>  {
> -	hlist_del(&event->node);
> +	hash_del(&event->node);
>  	free_trace_event_type(event->type);
>  	return 0;
>  }


^ permalink raw reply	[flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-03-23 13:28 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2025-03-19 19:05 [PATCH] tracing: Use hashtable.h for event_hash Sasha Levin
2025-03-23 12:39 [for-next][PATCH 05/10] " Steven Rostedt
2025-03-23 13:28 ` [PATCH] " Sasha Levin

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®