[PATCH v2] perf lock: Fix parse_lock_type which only retrieve one lock flag

Chun-Tse Shao posted 1 patch 1 year, 2 months ago
tools/perf/builtin-lock.c | 93 ++++++++++++++++++++++++++-------------
1 file changed, 62 insertions(+), 31 deletions(-)
[PATCH v2] perf lock: Fix parse_lock_type which only retrieve one lock flag
Posted by Chun-Tse Shao 1 year, 2 months ago
`parse_lock_type` can only add the first lock flag in `lock_type_table`
given input `str`. For example, for `Y rwlock`, it only adds `rwlock:R`
into this perf session. Another example is for `-Y mutex`, it only adds
the mutex without `LCB_F_SPIN` flag. The patch fixes this issue, makes
sure both `rwlock:R` and `rwlock:W` will be added with `-Y rwlock`, and
so on.

Testing:
  $ ./perf lock con -ab -Y mutex,rwlock -- perf bench sched pipe
  # Running 'sched/pipe' benchmark:
  # Executed 1000000 pipe operations between two processes

       Total time: 8.425 [sec]

         8.425402 usecs/op
           118688 ops/sec
   contended   total wait     max wait     avg wait         type   caller

         194      1.68 ms     44.16 us      8.66 us        mutex   pipe_read+0x57
          10    423.03 us     44.27 us     42.30 us     rwlock:W   do_exit+0x365
          54    254.67 us     58.87 us      4.72 us        mutex   pipe_write+0x50
          21    146.64 us     11.54 us      6.98 us        mutex   pipe_read+0x282
          10    141.27 us     20.62 us     14.13 us     rwlock:W   release_task+0x6f
           5     58.92 us     16.37 us     11.78 us        mutex   do_epoll_wait+0x24d
           3     29.81 us     17.66 us      9.94 us        mutex   do_epoll_ctl+0x6c1
           4     26.82 us     11.02 us      6.70 us        mutex   do_epoll_wait+0x24d
           2     18.32 us     12.49 us      9.16 us     rwlock:W   do_epoll_wait+0x255
           1     11.34 us     11.34 us     11.34 us     rwlock:W   ep_done_scan+0x2d
           1     11.02 us     11.02 us     11.02 us     rwlock:R   mm_update_next_owner+0x4e
           1     10.60 us     10.60 us     10.60 us     rwlock:W   do_epoll_ctl+0xb65
           1      9.90 us      9.90 us      9.90 us     rwlock:W   do_exit+0x365

Fixes: d783ea8f62c4 ("perf lock contention: Simplify parse_lock_type()")
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
---
 tools/perf/builtin-lock.c | 93 ++++++++++++++++++++++++++-------------
 1 file changed, 62 insertions(+), 31 deletions(-)

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 062e2b56a2ab..052dbf423efd 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -15,6 +15,7 @@
 #include "util/lock-contention.h"
 #include "util/bpf_skel/lock_data.h"
 
+#include <string.h>
 #include <subcmd/pager.h>
 #include <subcmd/parse-options.h>
 #include "util/trace-event.h"
@@ -1575,8 +1576,13 @@ static void sort_result(void)
 
 static const struct {
 	unsigned int flags;
-	const char *str;
+	/* Name of the lock. */
 	const char *name;
+	/*
+	 * Name of the group this lock belongs to.
+	 * For example, both rwlock:R and rwlock:W belong to rwlock.
+	 */
+	const char *group;
 } lock_type_table[] = {
 	{ 0,				"semaphore",	"semaphore" },
 	{ LCB_F_SPIN,			"spinlock",	"spinlock" },
@@ -1591,42 +1597,38 @@ static const struct {
 	{ LCB_F_PERCPU | LCB_F_WRITE,	"pcpu-sem:W",	"percpu-rwsem" },
 	{ LCB_F_MUTEX,			"mutex",	"mutex" },
 	{ LCB_F_MUTEX | LCB_F_SPIN,	"mutex",	"mutex" },
-	/* alias for get_type_flag() */
-	{ LCB_F_MUTEX | LCB_F_SPIN,	"mutex-spin",	"mutex" },
 };
 
-static const char *get_type_str(unsigned int flags)
+static const char *get_type_name(unsigned int flags)
 {
 	flags &= LCB_F_MAX_FLAGS - 1;
 
 	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
 		if (lock_type_table[i].flags == flags)
-			return lock_type_table[i].str;
+			return lock_type_table[i].name;
 	}
 	return "unknown";
 }
 
-static const char *get_type_name(unsigned int flags)
+static const char *get_type_group(unsigned int flags)
 {
 	flags &= LCB_F_MAX_FLAGS - 1;
 
 	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
 		if (lock_type_table[i].flags == flags)
-			return lock_type_table[i].name;
+			return lock_type_table[i].group;
 	}
 	return "unknown";
 }
 
-static unsigned int get_type_flag(const char *str)
+static unsigned int get_type_flags_by_name(const char *name)
 {
 	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
-		if (!strcmp(lock_type_table[i].name, str))
-			return lock_type_table[i].flags;
-	}
-	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
-		if (!strcmp(lock_type_table[i].str, str))
+		if (!strcmp(lock_type_table[i].name, name))
 			return lock_type_table[i].flags;
 	}
+
+	pr_err("Unknown lock flags: %s\n", name);
 	return UINT_MAX;
 }
 
@@ -1732,7 +1734,8 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
 
 	switch (aggr_mode) {
 	case LOCK_AGGR_CALLER:
-		fprintf(lock_output, "  %10s   %s\n", get_type_str(st->flags), st->name);
+		fprintf(lock_output, "  %10s   %s\n",
+			get_type_name(st->flags), st->name);
 		break;
 	case LOCK_AGGR_TASK:
 		pid = st->addr;
@@ -1742,7 +1745,7 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
 		break;
 	case LOCK_AGGR_ADDR:
 		fprintf(lock_output, "  %016llx   %s (%s)\n", (unsigned long long)st->addr,
-			st->name, get_type_name(st->flags));
+			st->name, get_type_group(st->flags));
 		break;
 	case LOCK_AGGR_CGROUP:
 		fprintf(lock_output, "  %s\n", st->name);
@@ -1783,7 +1786,8 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
 
 	switch (aggr_mode) {
 	case LOCK_AGGR_CALLER:
-		fprintf(lock_output, "%s%s %s", get_type_str(st->flags), sep, st->name);
+		fprintf(lock_output, "%s%s %s",
+			get_type_name(st->flags), sep, st->name);
 		if (verbose <= 0)
 			fprintf(lock_output, "\n");
 		break;
@@ -1795,7 +1799,7 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
 		break;
 	case LOCK_AGGR_ADDR:
 		fprintf(lock_output, "%llx%s %s%s %s\n", (unsigned long long)st->addr, sep,
-			st->name, sep, get_type_name(st->flags));
+			st->name, sep, get_type_group(st->flags));
 		break;
 	case LOCK_AGGR_CGROUP:
 		fprintf(lock_output, "%s\n",st->name);
@@ -2338,41 +2342,68 @@ static bool add_lock_type(unsigned int flags)
 	unsigned int *tmp;
 
 	tmp = realloc(filters.types, (filters.nr_types + 1) * sizeof(*filters.types));
-	if (tmp == NULL)
+	if (tmp == NULL) {
+		pr_err("Failed to add lock flags: %u\n", flags);
 		return false;
+	}
 
 	tmp[filters.nr_types++] = flags;
 	filters.types = tmp;
 	return true;
 }
 
-static int parse_lock_type(const struct option *opt __maybe_unused, const char *str,
-			   int unset __maybe_unused)
+static int parse_lock_type(const struct option *opt __maybe_unused,
+			   const char *str, int unset __maybe_unused)
 {
 	char *s, *tmp, *tok;
-	int ret = 0;
 
 	s = strdup(str);
 	if (s == NULL)
 		return -1;
 
-	for (tok = strtok_r(s, ", ", &tmp); tok; tok = strtok_r(NULL, ", ", &tmp)) {
-		unsigned int flags = get_type_flag(tok);
+	for (tok = strtok_r(s, ", ", &tmp); tok;
+	     tok = strtok_r(NULL, ", ", &tmp)) {
+		bool found = false;
 
-		if (flags == -1U) {
-			pr_err("Unknown lock flags: %s\n", tok);
-			ret = -1;
-			break;
+		/* `tok` is a lock name if it contains ':'. */
+		if (strchr(tok, ':')) {
+			unsigned int flags = get_type_flags_by_name(tok);
+
+			if (flags == UINT_MAX || !add_lock_type(flags)) {
+				free(s);
+				return -1;
+			}
+			continue;
 		}
 
-		if (!add_lock_type(flags)) {
-			ret = -1;
-			break;
+		/* Otherwise look up flags by lock group */
+		/*
+		 * By documentation, `percpu-rwmem` should be `pcpu-sem`.
+		 * For backward compatibility, we replace pcpu-sem with percpu-rwmem.
+		 */
+		if (!strcmp(tok, "pcpu-sem"))
+			tok = (char *)"percpu-rwsem";
+
+		for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
+			if (!strcmp(lock_type_table[i].group, tok)) {
+				if (add_lock_type(lock_type_table[i].flags)) {
+					found = true;
+				} else {
+					free(s);
+					return -1;
+				}
+			}
+		}
+
+		if (!found) {
+			pr_err("Unknown lock flags: %s\n", tok);
+			free(s);
+			return -1;
 		}
 	}
 
 	free(s);
-	return ret;
+	return 0;
 }
 
 static bool add_lock_addr(unsigned long addr)
-- 
2.47.0.371.ga323438b13-goog
Re: [PATCH v2] perf lock: Fix parse_lock_type which only retrieve one lock flag
Posted by Namhyung Kim 1 year, 2 months ago
Hello,

On Fri, Nov 22, 2024 at 12:27:51AM +0000, Chun-Tse Shao wrote:
> `parse_lock_type` can only add the first lock flag in `lock_type_table`
> given input `str`. For example, for `Y rwlock`, it only adds `rwlock:R`
> into this perf session. Another example is for `-Y mutex`, it only adds
> the mutex without `LCB_F_SPIN` flag. The patch fixes this issue, makes
> sure both `rwlock:R` and `rwlock:W` will be added with `-Y rwlock`, and
> so on.
> 
> Testing:
>   $ ./perf lock con -ab -Y mutex,rwlock -- perf bench sched pipe
>   # Running 'sched/pipe' benchmark:
>   # Executed 1000000 pipe operations between two processes
> 
>        Total time: 8.425 [sec]
> 
>          8.425402 usecs/op
>            118688 ops/sec
>    contended   total wait     max wait     avg wait         type   caller
> 
>          194      1.68 ms     44.16 us      8.66 us        mutex   pipe_read+0x57
>           10    423.03 us     44.27 us     42.30 us     rwlock:W   do_exit+0x365
>           54    254.67 us     58.87 us      4.72 us        mutex   pipe_write+0x50
>           21    146.64 us     11.54 us      6.98 us        mutex   pipe_read+0x282
>           10    141.27 us     20.62 us     14.13 us     rwlock:W   release_task+0x6f
>            5     58.92 us     16.37 us     11.78 us        mutex   do_epoll_wait+0x24d
>            3     29.81 us     17.66 us      9.94 us        mutex   do_epoll_ctl+0x6c1
>            4     26.82 us     11.02 us      6.70 us        mutex   do_epoll_wait+0x24d
>            2     18.32 us     12.49 us      9.16 us     rwlock:W   do_epoll_wait+0x255
>            1     11.34 us     11.34 us     11.34 us     rwlock:W   ep_done_scan+0x2d
>            1     11.02 us     11.02 us     11.02 us     rwlock:R   mm_update_next_owner+0x4e
>            1     10.60 us     10.60 us     10.60 us     rwlock:W   do_epoll_ctl+0xb65
>            1      9.90 us      9.90 us      9.90 us     rwlock:W   do_exit+0x365
> 
> Fixes: d783ea8f62c4 ("perf lock contention: Simplify parse_lock_type()")
> Signed-off-by: Chun-Tse Shao <ctshao@google.com>
> ---
>  tools/perf/builtin-lock.c | 93 ++++++++++++++++++++++++++-------------
>  1 file changed, 62 insertions(+), 31 deletions(-)
> 
> diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> index 062e2b56a2ab..052dbf423efd 100644
> --- a/tools/perf/builtin-lock.c
> +++ b/tools/perf/builtin-lock.c
> @@ -15,6 +15,7 @@
>  #include "util/lock-contention.h"
>  #include "util/bpf_skel/lock_data.h"
>  
> +#include <string.h>
>  #include <subcmd/pager.h>
>  #include <subcmd/parse-options.h>
>  #include "util/trace-event.h"
> @@ -1575,8 +1576,13 @@ static void sort_result(void)
>  
>  static const struct {
>  	unsigned int flags;
> -	const char *str;
> +	/* Name of the lock. */
>  	const char *name;

I think this is the name of flag or access - read or write.


> +	/*
> +	 * Name of the group this lock belongs to.
> +	 * For example, both rwlock:R and rwlock:W belong to rwlock.
> +	 */
> +	const char *group;

And this is the name of the lock (type) - rwlock or rwsem.


>  } lock_type_table[] = {
>  	{ 0,				"semaphore",	"semaphore" },
>  	{ LCB_F_SPIN,			"spinlock",	"spinlock" },
> @@ -1591,42 +1597,38 @@ static const struct {
>  	{ LCB_F_PERCPU | LCB_F_WRITE,	"pcpu-sem:W",	"percpu-rwsem" },
>  	{ LCB_F_MUTEX,			"mutex",	"mutex" },
>  	{ LCB_F_MUTEX | LCB_F_SPIN,	"mutex",	"mutex" },
> -	/* alias for get_type_flag() */
> -	{ LCB_F_MUTEX | LCB_F_SPIN,	"mutex-spin",	"mutex" },
>  };
>  
> -static const char *get_type_str(unsigned int flags)
> +static const char *get_type_name(unsigned int flags)
>  {
>  	flags &= LCB_F_MAX_FLAGS - 1;
>  
>  	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
>  		if (lock_type_table[i].flags == flags)
> -			return lock_type_table[i].str;
> +			return lock_type_table[i].name;
>  	}
>  	return "unknown";
>  }
>  
> -static const char *get_type_name(unsigned int flags)
> +static const char *get_type_group(unsigned int flags)
>  {
>  	flags &= LCB_F_MAX_FLAGS - 1;
>  
>  	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
>  		if (lock_type_table[i].flags == flags)
> -			return lock_type_table[i].name;
> +			return lock_type_table[i].group;
>  	}
>  	return "unknown";
>  }
>  
> -static unsigned int get_type_flag(const char *str)
> +static unsigned int get_type_flags_by_name(const char *name)
>  {
>  	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
> -		if (!strcmp(lock_type_table[i].name, str))
> -			return lock_type_table[i].flags;
> -	}
> -	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
> -		if (!strcmp(lock_type_table[i].str, str))
> +		if (!strcmp(lock_type_table[i].name, name))
>  			return lock_type_table[i].flags;
>  	}
> +
> +	pr_err("Unknown lock flags: %s\n", name);

I'm not sure if there will be another caller, but it seems better to
have this error message in the parse function directly.


>  	return UINT_MAX;
>  }
>  
> @@ -1732,7 +1734,8 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
>  
>  	switch (aggr_mode) {
>  	case LOCK_AGGR_CALLER:
> -		fprintf(lock_output, "  %10s   %s\n", get_type_str(st->flags), st->name);
> +		fprintf(lock_output, "  %10s   %s\n",
> +			get_type_name(st->flags), st->name);
>  		break;
>  	case LOCK_AGGR_TASK:
>  		pid = st->addr;
> @@ -1742,7 +1745,7 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
>  		break;
>  	case LOCK_AGGR_ADDR:
>  		fprintf(lock_output, "  %016llx   %s (%s)\n", (unsigned long long)st->addr,
> -			st->name, get_type_name(st->flags));
> +			st->name, get_type_group(st->flags));
>  		break;
>  	case LOCK_AGGR_CGROUP:
>  		fprintf(lock_output, "  %s\n", st->name);
> @@ -1783,7 +1786,8 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
>  
>  	switch (aggr_mode) {
>  	case LOCK_AGGR_CALLER:
> -		fprintf(lock_output, "%s%s %s", get_type_str(st->flags), sep, st->name);
> +		fprintf(lock_output, "%s%s %s",
> +			get_type_name(st->flags), sep, st->name);
>  		if (verbose <= 0)
>  			fprintf(lock_output, "\n");
>  		break;
> @@ -1795,7 +1799,7 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
>  		break;
>  	case LOCK_AGGR_ADDR:
>  		fprintf(lock_output, "%llx%s %s%s %s\n", (unsigned long long)st->addr, sep,
> -			st->name, sep, get_type_name(st->flags));
> +			st->name, sep, get_type_group(st->flags));
>  		break;
>  	case LOCK_AGGR_CGROUP:
>  		fprintf(lock_output, "%s\n",st->name);
> @@ -2338,41 +2342,68 @@ static bool add_lock_type(unsigned int flags)
>  	unsigned int *tmp;
>  
>  	tmp = realloc(filters.types, (filters.nr_types + 1) * sizeof(*filters.types));
> -	if (tmp == NULL)
> +	if (tmp == NULL) {
> +		pr_err("Failed to add lock flags: %u\n", flags);
>  		return false;
> +	}
>  
>  	tmp[filters.nr_types++] = flags;
>  	filters.types = tmp;
>  	return true;
>  }
>  
> -static int parse_lock_type(const struct option *opt __maybe_unused, const char *str,
> -			   int unset __maybe_unused)
> +static int parse_lock_type(const struct option *opt __maybe_unused,
> +			   const char *str, int unset __maybe_unused)
>  {
>  	char *s, *tmp, *tok;
> -	int ret = 0;
>  
>  	s = strdup(str);
>  	if (s == NULL)
>  		return -1;
>  
> -	for (tok = strtok_r(s, ", ", &tmp); tok; tok = strtok_r(NULL, ", ", &tmp)) {
> -		unsigned int flags = get_type_flag(tok);
> +	for (tok = strtok_r(s, ", ", &tmp); tok;
> +	     tok = strtok_r(NULL, ", ", &tmp)) {

I think you changed this because of the 80 column limit.  But I think
it's recently increased to 100 so you don't need to change this line
uncessarily.

Other lines containing actual changes may be accceptable.  It's up to
you but I generally prefer smaller changes.


> +		bool found = false;
>  
> -		if (flags == -1U) {
> -			pr_err("Unknown lock flags: %s\n", tok);
> -			ret = -1;
> -			break;
> +		/* `tok` is a lock name if it contains ':'. */
> +		if (strchr(tok, ':')) {
> +			unsigned int flags = get_type_flags_by_name(tok);
> +
> +			if (flags == UINT_MAX || !add_lock_type(flags)) {
> +				free(s);
> +				return -1;
> +			}
> +			continue;
>  		}
>  
> -		if (!add_lock_type(flags)) {
> -			ret = -1;
> -			break;
> +		/* Otherwise look up flags by lock group */
> +		/*
> +		 * By documentation, `percpu-rwmem` should be `pcpu-sem`.
> +		 * For backward compatibility, we replace pcpu-sem with percpu-rwmem.
> +		 */
> +		if (!strcmp(tok, "pcpu-sem"))
> +			tok = (char *)"percpu-rwsem";

Can you please split this into a separate fix?

Thanks,
Namhyung

> +
> +		for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
> +			if (!strcmp(lock_type_table[i].group, tok)) {
> +				if (add_lock_type(lock_type_table[i].flags)) {
> +					found = true;
> +				} else {
> +					free(s);
> +					return -1;
> +				}
> +			}
> +		}
> +
> +		if (!found) {
> +			pr_err("Unknown lock flags: %s\n", tok);
> +			free(s);
> +			return -1;
>  		}
>  	}
>  
>  	free(s);
> -	return ret;
> +	return 0;
>  }
>  
>  static bool add_lock_addr(unsigned long addr)
> -- 
> 2.47.0.371.ga323438b13-goog
>
Re: [PATCH v2] perf lock: Fix parse_lock_type which only retrieve one lock flag
Posted by Chun-Tse Shao 1 year, 2 months ago
Thanks Namhyung! please check my v3 patches:
https://lore.kernel.org/all/20241126212255.3793822-1-ctshao@google.com/

On Mon, Nov 25, 2024 at 10:07 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> Hello,
>
> On Fri, Nov 22, 2024 at 12:27:51AM +0000, Chun-Tse Shao wrote:
> > `parse_lock_type` can only add the first lock flag in `lock_type_table`
> > given input `str`. For example, for `Y rwlock`, it only adds `rwlock:R`
> > into this perf session. Another example is for `-Y mutex`, it only adds
> > the mutex without `LCB_F_SPIN` flag. The patch fixes this issue, makes
> > sure both `rwlock:R` and `rwlock:W` will be added with `-Y rwlock`, and
> > so on.
> >
> > Testing:
> >   $ ./perf lock con -ab -Y mutex,rwlock -- perf bench sched pipe
> >   # Running 'sched/pipe' benchmark:
> >   # Executed 1000000 pipe operations between two processes
> >
> >        Total time: 8.425 [sec]
> >
> >          8.425402 usecs/op
> >            118688 ops/sec
> >    contended   total wait     max wait     avg wait         type   caller
> >
> >          194      1.68 ms     44.16 us      8.66 us        mutex   pipe_read+0x57
> >           10    423.03 us     44.27 us     42.30 us     rwlock:W   do_exit+0x365
> >           54    254.67 us     58.87 us      4.72 us        mutex   pipe_write+0x50
> >           21    146.64 us     11.54 us      6.98 us        mutex   pipe_read+0x282
> >           10    141.27 us     20.62 us     14.13 us     rwlock:W   release_task+0x6f
> >            5     58.92 us     16.37 us     11.78 us        mutex   do_epoll_wait+0x24d
> >            3     29.81 us     17.66 us      9.94 us        mutex   do_epoll_ctl+0x6c1
> >            4     26.82 us     11.02 us      6.70 us        mutex   do_epoll_wait+0x24d
> >            2     18.32 us     12.49 us      9.16 us     rwlock:W   do_epoll_wait+0x255
> >            1     11.34 us     11.34 us     11.34 us     rwlock:W   ep_done_scan+0x2d
> >            1     11.02 us     11.02 us     11.02 us     rwlock:R   mm_update_next_owner+0x4e
> >            1     10.60 us     10.60 us     10.60 us     rwlock:W   do_epoll_ctl+0xb65
> >            1      9.90 us      9.90 us      9.90 us     rwlock:W   do_exit+0x365
> >
> > Fixes: d783ea8f62c4 ("perf lock contention: Simplify parse_lock_type()")
> > Signed-off-by: Chun-Tse Shao <ctshao@google.com>
> > ---
> >  tools/perf/builtin-lock.c | 93 ++++++++++++++++++++++++++-------------
> >  1 file changed, 62 insertions(+), 31 deletions(-)
> >
> > diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> > index 062e2b56a2ab..052dbf423efd 100644
> > --- a/tools/perf/builtin-lock.c
> > +++ b/tools/perf/builtin-lock.c
> > @@ -15,6 +15,7 @@
> >  #include "util/lock-contention.h"
> >  #include "util/bpf_skel/lock_data.h"
> >
> > +#include <string.h>
> >  #include <subcmd/pager.h>
> >  #include <subcmd/parse-options.h>
> >  #include "util/trace-event.h"
> > @@ -1575,8 +1576,13 @@ static void sort_result(void)
> >
> >  static const struct {
> >       unsigned int flags;
> > -     const char *str;
> > +     /* Name of the lock. */
> >       const char *name;
>
> I think this is the name of flag or access - read or write.
>

Rename to `flags_name`.

>
> > +     /*
> > +      * Name of the group this lock belongs to.
> > +      * For example, both rwlock:R and rwlock:W belong to rwlock.
> > +      */
> > +     const char *group;
>
> And this is the name of the lock (type) - rwlock or rwsem.
>

Rename to `lock_name`.

>
> >  } lock_type_table[] = {
> >       { 0,                            "semaphore",    "semaphore" },
> >       { LCB_F_SPIN,                   "spinlock",     "spinlock" },
> > @@ -1591,42 +1597,38 @@ static const struct {
> >       { LCB_F_PERCPU | LCB_F_WRITE,   "pcpu-sem:W",   "percpu-rwsem" },
> >       { LCB_F_MUTEX,                  "mutex",        "mutex" },
> >       { LCB_F_MUTEX | LCB_F_SPIN,     "mutex",        "mutex" },
> > -     /* alias for get_type_flag() */
> > -     { LCB_F_MUTEX | LCB_F_SPIN,     "mutex-spin",   "mutex" },
> >  };
> >
> > -static const char *get_type_str(unsigned int flags)
> > +static const char *get_type_name(unsigned int flags)
> >  {
> >       flags &= LCB_F_MAX_FLAGS - 1;
> >
> >       for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
> >               if (lock_type_table[i].flags == flags)
> > -                     return lock_type_table[i].str;
> > +                     return lock_type_table[i].name;
> >       }
> >       return "unknown";
> >  }
> >
> > -static const char *get_type_name(unsigned int flags)
> > +static const char *get_type_group(unsigned int flags)
> >  {
> >       flags &= LCB_F_MAX_FLAGS - 1;
> >
> >       for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
> >               if (lock_type_table[i].flags == flags)
> > -                     return lock_type_table[i].name;
> > +                     return lock_type_table[i].group;
> >       }
> >       return "unknown";
> >  }
> >
> > -static unsigned int get_type_flag(const char *str)
> > +static unsigned int get_type_flags_by_name(const char *name)
> >  {
> >       for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
> > -             if (!strcmp(lock_type_table[i].name, str))
> > -                     return lock_type_table[i].flags;
> > -     }
> > -     for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
> > -             if (!strcmp(lock_type_table[i].str, str))
> > +             if (!strcmp(lock_type_table[i].name, name))
> >                       return lock_type_table[i].flags;
> >       }
> > +
> > +     pr_err("Unknown lock flags: %s\n", name);
>
> I'm not sure if there will be another caller, but it seems better to
> have this error message in the parse function directly.
>

Done. I removed this function since imo it did not help readability,
and was only used for once.

>
> >       return UINT_MAX;
> >  }
> >
> > @@ -1732,7 +1734,8 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
> >
> >       switch (aggr_mode) {
> >       case LOCK_AGGR_CALLER:
> > -             fprintf(lock_output, "  %10s   %s\n", get_type_str(st->flags), st->name);
> > +             fprintf(lock_output, "  %10s   %s\n",
> > +                     get_type_name(st->flags), st->name);
> >               break;
> >       case LOCK_AGGR_TASK:
> >               pid = st->addr;
> > @@ -1742,7 +1745,7 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
> >               break;
> >       case LOCK_AGGR_ADDR:
> >               fprintf(lock_output, "  %016llx   %s (%s)\n", (unsigned long long)st->addr,
> > -                     st->name, get_type_name(st->flags));
> > +                     st->name, get_type_group(st->flags));
> >               break;
> >       case LOCK_AGGR_CGROUP:
> >               fprintf(lock_output, "  %s\n", st->name);
> > @@ -1783,7 +1786,8 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
> >
> >       switch (aggr_mode) {
> >       case LOCK_AGGR_CALLER:
> > -             fprintf(lock_output, "%s%s %s", get_type_str(st->flags), sep, st->name);
> > +             fprintf(lock_output, "%s%s %s",
> > +                     get_type_name(st->flags), sep, st->name);
> >               if (verbose <= 0)
> >                       fprintf(lock_output, "\n");
> >               break;
> > @@ -1795,7 +1799,7 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
> >               break;
> >       case LOCK_AGGR_ADDR:
> >               fprintf(lock_output, "%llx%s %s%s %s\n", (unsigned long long)st->addr, sep,
> > -                     st->name, sep, get_type_name(st->flags));
> > +                     st->name, sep, get_type_group(st->flags));
> >               break;
> >       case LOCK_AGGR_CGROUP:
> >               fprintf(lock_output, "%s\n",st->name);
> > @@ -2338,41 +2342,68 @@ static bool add_lock_type(unsigned int flags)
> >       unsigned int *tmp;
> >
> >       tmp = realloc(filters.types, (filters.nr_types + 1) * sizeof(*filters.types));
> > -     if (tmp == NULL)
> > +     if (tmp == NULL) {
> > +             pr_err("Failed to add lock flags: %u\n", flags);
> >               return false;
> > +     }
> >
> >       tmp[filters.nr_types++] = flags;
> >       filters.types = tmp;
> >       return true;
> >  }
> >
> > -static int parse_lock_type(const struct option *opt __maybe_unused, const char *str,
> > -                        int unset __maybe_unused)
> > +static int parse_lock_type(const struct option *opt __maybe_unused,
> > +                        const char *str, int unset __maybe_unused)
> >  {
> >       char *s, *tmp, *tok;
> > -     int ret = 0;
> >
> >       s = strdup(str);
> >       if (s == NULL)
> >               return -1;
> >
> > -     for (tok = strtok_r(s, ", ", &tmp); tok; tok = strtok_r(NULL, ", ", &tmp)) {
> > -             unsigned int flags = get_type_flag(tok);
> > +     for (tok = strtok_r(s, ", ", &tmp); tok;
> > +          tok = strtok_r(NULL, ", ", &tmp)) {
>
> I think you changed this because of the 80 column limit.  But I think
> it's recently increased to 100 so you don't need to change this line
> uncessarily.
>
> Other lines containing actual changes may be accceptable.  It's up to
> you but I generally prefer smaller changes.
>

Done.

>
> > +             bool found = false;
> >
> > -             if (flags == -1U) {
> > -                     pr_err("Unknown lock flags: %s\n", tok);
> > -                     ret = -1;
> > -                     break;
> > +             /* `tok` is a lock name if it contains ':'. */
> > +             if (strchr(tok, ':')) {
> > +                     unsigned int flags = get_type_flags_by_name(tok);
> > +
> > +                     if (flags == UINT_MAX || !add_lock_type(flags)) {
> > +                             free(s);
> > +                             return -1;
> > +                     }
> > +                     continue;
> >               }
> >
> > -             if (!add_lock_type(flags)) {
> > -                     ret = -1;
> > -                     break;
> > +             /* Otherwise look up flags by lock group */
> > +             /*
> > +              * By documentation, `percpu-rwmem` should be `pcpu-sem`.
> > +              * For backward compatibility, we replace pcpu-sem with percpu-rwmem.
> > +              */
> > +             if (!strcmp(tok, "pcpu-sem"))
> > +                     tok = (char *)"percpu-rwsem";
>
> Can you please split this into a separate fix?
>

Done. Now I have two patches, the first one is for renaming, the
second one is for parsing logic.

> Thanks,
> Namhyung
>
> > +
> > +             for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
> > +                     if (!strcmp(lock_type_table[i].group, tok)) {
> > +                             if (add_lock_type(lock_type_table[i].flags)) {
> > +                                     found = true;
> > +                             } else {
> > +                                     free(s);
> > +                                     return -1;
> > +                             }
> > +                     }
> > +             }
> > +
> > +             if (!found) {
> > +                     pr_err("Unknown lock flags: %s\n", tok);
> > +                     free(s);
> > +                     return -1;
> >               }
> >       }
> >
> >       free(s);
> > -     return ret;
> > +     return 0;
> >  }
> >
> >  static bool add_lock_addr(unsigned long addr)
> > --
> > 2.47.0.371.ga323438b13-goog
> >