Re: [PATCH v2 36/40] tracing: Remove lookups from tracing_map hitcount

[Masami Hiramatsu]

Hi Tom,

On Tue,  5 Sep 2017 16:57:48 -0500
Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx> wrote:

> Lookups inflate the hitcount, making it essentially useless.  Only
> inserts and updates should really affect the hitcount anyway, so
> explicitly filter lookups out.
> 
> Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
> ---
>  kernel/trace/tracing_map.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
> index a4e5a56..f8e2338 100644
> --- a/kernel/trace/tracing_map.c
> +++ b/kernel/trace/tracing_map.c
> @@ -538,7 +538,8 @@ static inline bool keys_match(void *key, void *test_key, unsigned key_size)
>  		if (test_key && test_key == key_hash) {
>  			if (entry->val &&
>  			    keys_match(key, entry->val->key, map->key_size)) {
> -				atomic64_inc(&map->hits);
> +				if (!lookup_only)
> +					atomic64_inc(&map->hits);

Is this a kind of bugfix for current code?
If so, such patch can be posted in separate series.

Thank you,

>  				return entry->val;
>  			} else if (unlikely(!entry->val)) {
>  				/*
> -- 
> 1.9.3
> 


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>