This is a note to let you know that I've just added the patch titled
perf lock: Fix parse_lock_type which only retrieve one lock flag
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-lock-fix-parse_lock_type-which-only-retrieve-on.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit eefc3ca586a275bcee5f4cbe40e76d4e10a075a0
Author: Chun-Tse Shao <ctshao@xxxxxxxxxx>
Date: Thu Jan 16 15:58:14 2025 -0800
perf lock: Fix parse_lock_type which only retrieve one lock flag
[ Upstream commit 1be9264158ef4818393e5d8144887a1a5d3cc480 ]
`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: 9.313 [sec]
9.313976 usecs/op
107365 ops/sec
contended total wait max wait avg wait type caller
176 1.65 ms 19.43 us 9.38 us mutex pipe_read+0x57
34 180.14 us 10.93 us 5.30 us mutex pipe_write+0x50
7 77.48 us 16.09 us 11.07 us mutex do_epoll_wait+0x24d
7 74.70 us 13.50 us 10.67 us mutex do_epoll_wait+0x24d
3 35.97 us 14.44 us 11.99 us rwlock:W ep_done_scan+0x2d
3 35.00 us 12.23 us 11.66 us rwlock:W do_epoll_wait+0x255
2 15.88 us 11.96 us 7.94 us rwlock:W do_epoll_wait+0x47c
1 15.23 us 15.23 us 15.23 us rwlock:W do_epoll_wait+0x4d0
1 14.26 us 14.26 us 14.26 us rwlock:W ep_done_scan+0x2d
2 14.00 us 7.99 us 7.00 us mutex pipe_read+0x282
1 12.29 us 12.29 us 12.29 us rwlock:R ep_poll_callback+0x35
1 12.02 us 12.02 us 12.02 us rwlock:W do_epoll_ctl+0xb65
1 10.25 us 10.25 us 10.25 us rwlock:R ep_poll_callback+0x35
1 7.86 us 7.86 us 7.86 us mutex do_epoll_ctl+0x6c1
1 5.04 us 5.04 us 5.04 us mutex do_epoll_ctl+0x3d4
[namhyung: Add a comment and rename to 'mutex:spin' for consistency
Fixes: d783ea8f62c4 ("perf lock contention: Simplify parse_lock_type()")
Reviewed-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Chun-Tse Shao <ctshao@xxxxxxxxxx>
Cc: nick.forrington@xxxxxxx
Link: https://lore.kernel.org/r/20250116235838.2769691-1-ctshao@xxxxxxxxxx
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index fcb32c58bee7e..bd24ed0af208a 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -1591,8 +1591,8 @@ 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" },
+ /* alias for optimistic spinning only */
+ { LCB_F_MUTEX | LCB_F_SPIN, "mutex:spin", "mutex-spin" },
};
static const char *get_type_str(unsigned int flags)
@@ -1617,19 +1617,6 @@ static const char *get_type_name(unsigned int flags)
return "unknown";
}
-static unsigned int get_type_flag(const char *str)
-{
- 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))
- return lock_type_table[i].flags;
- }
- return UINT_MAX;
-}
-
static void lock_filter_finish(void)
{
zfree(&filters.types);
@@ -2321,29 +2308,58 @@ static int parse_lock_type(const struct option *opt __maybe_unused, const char *
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);
+ bool found = false;
- if (flags == -1U) {
- pr_err("Unknown lock flags: %s\n", tok);
- ret = -1;
- break;
+ /* `tok` is `str` in `lock_type_table` if it contains ':'. */
+ if (strchr(tok, ':')) {
+ for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
+ if (!strcmp(lock_type_table[i].str, tok) &&
+ add_lock_type(lock_type_table[i].flags)) {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ pr_err("Unknown lock flags name: %s\n", tok);
+ free(s);
+ return -1;
+ }
+
+ continue;
}
- if (!add_lock_type(flags)) {
- ret = -1;
- break;
+ /*
+ * Otherwise `tok` is `name` in `lock_type_table`.
+ * Single lock name could contain multiple flags.
+ */
+ 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)) {
+ found = true;
+ } else {
+ free(s);
+ return -1;
+ }
+ }
}
+
+ if (!found) {
+ pr_err("Unknown lock name: %s\n", tok);
+ free(s);
+ return -1;
+ }
+
}
free(s);
- return ret;
+ return 0;
}
static bool add_lock_addr(unsigned long addr)
