linux-kernel - Re: [PATCH v4 2/3] perf lock: Fix the wrong name percpu-rwsem

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Message-ID: <Z1dy2Svj6gddulHf@google.com>
Date: Mon, 9 Dec 2024 14:44:41 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Chun-Tse Shao <ctshao@...gle.com>
Cc: linux-kernel@...r.kernel.org, peterz@...radead.org, mingo@...hat.com,
	acme@...nel.org, mark.rutland@....com,
	alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
	irogers@...gle.com, adrian.hunter@...el.com,
	kan.liang@...ux.intel.com, linux-perf-users@...r.kernel.org
Subject: Re: [PATCH v4 2/3] perf lock: Fix the wrong name percpu-rwsem

On Mon, Dec 09, 2024 at 12:01:01PM -0800, Chun-Tse Shao wrote:
> In `perf lock --help`, the name of `percpu-rwsem` should be
> `pcpu-rwsem`. This patch fixes the naming in `lock_type_table`, and also
> replaces the mismatched name `percpu-rwsem` before parsing it for
> backward compatibility.
> 
> Tested `./perf lock con -ab -Y pcpu-sem` and `./perf lock con -ab -Y
> percpu-rwsem`
> 
> Fixes: 4f701063bfa2 ("perf lock contention: Show lock type with address")
> Signed-off-by: Chun-Tse Shao <ctshao@...gle.com>
> ---
>  tools/perf/builtin-lock.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> index 7e36bbe3cb80..264acfa648e4 100644
> --- a/tools/perf/builtin-lock.c
> +++ b/tools/perf/builtin-lock.c
> @@ -1587,8 +1587,8 @@ static const struct {
>  	{ LCB_F_RT,			"rt-mutex",	"rt-mutex" },
>  	{ LCB_F_RT | LCB_F_READ,	"rwlock-rt:R",	"rwlock-rt" },
>  	{ LCB_F_RT | LCB_F_WRITE,	"rwlock-rt:W",	"rwlock-rt" },
> -	{ LCB_F_PERCPU | LCB_F_READ,	"pcpu-sem:R",	"percpu-rwsem" },
> -	{ LCB_F_PERCPU | LCB_F_WRITE,	"pcpu-sem:W",	"percpu-rwsem" },
> +	{ LCB_F_PERCPU | LCB_F_READ,	"pcpu-sem:R",	"pcpu-sem" },
> +	{ LCB_F_PERCPU | LCB_F_WRITE,	"pcpu-sem:W",	"pcpu-sem" },

It'll change the output of perf lock con -l.


>  	{ LCB_F_MUTEX,			"mutex",	"mutex" },
>  	{ LCB_F_MUTEX | LCB_F_SPIN,	"mutex",	"mutex" },
>  };
> @@ -2365,7 +2365,11 @@ static int parse_lock_type(const struct option *opt __maybe_unused, const char *
>  		/*
>  		 * Otherwise `tok` is `name` in `lock_type_table`.
>  		 * Single lock name could contain multiple flags.
> +		 * By documentation, `percpu-rwmem` should be `pcpu-sem`.
> +		 * For backward compatibility, we replace `percpu-rwmem` with `pcpu-sem`.
>  		 */
> +		if (!strcmp(tok, "percpu-rwsem"))
> +			tok = (char *)"pcpu-sem";

I think you can do this in the other way around.

Thanks,
Namhyung


>  		for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
>  			if (!strcmp(lock_type_table[i].name, tok)) {
>  				if (add_lock_type(lock_type_table[i].flags)) {
> -- 
> 2.47.0.338.g60cca15819-goog
>