Re: [PATCH v2 12/16] perf lock: Move common lock contention code to new file

Namhyung Kim
2024-10-22T06:36:51Z

On Tue, Oct 15, 2024 at 09:24:11PM -0700, Ian Rogers wrote:
> Avoid references from util code to builtin-lock that require python
> stubs. Move the functions and related variables to
> util/lock-contention.c. Add max_stack_depth parameter to
> match_callstack_filter to avoid sharing a global variable.
>
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/builtin-lock.c | 137 +--------------------
> tools/perf/util/Build | 1 +
> tools/perf/util/bpf_lock_contention.c | 2 +-
> tools/perf/util/lock-contention.c | 170 ++++++++++++++++++++++++++
> tools/perf/util/lock-contention.h | 37 ++----
> tools/perf/util/python.c | 17 ---
> 6 files changed, 185 insertions(+), 179 deletions(-)
> create mode 100644 tools/perf/util/lock-contention.c
>
[SNIP]
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index 2a2f7780e595..ea2d9eced92e 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -121,6 +121,7 @@ perf-util-y += topdown.o
> perf-util-y += iostat.o
> perf-util-y += stream.o
> perf-util-y += kvm-stat.o
> +perf-util-y += lock-contention.o
> perf-util-$(CONFIG_AUXTRACE) += auxtrace.o
> perf-util-$(CONFIG_AUXTRACE) += intel-pt-decoder/
> perf-util-$(CONFIG_AUXTRACE) += intel-pt.o
> diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
> index 41a1ad087895..37e17c56f106 100644
> --- a/tools/perf/util/bpf_lock_contention.c
> +++ b/tools/perf/util/bpf_lock_contention.c
> @@ -458,7 +458,7 @@ int lock_contention_read(struct lock_contention *con)
> if (con->save_callstack) {
> bpf_map_lookup_elem(stack, &key.stack_id, stack_trace);
>
> - if (!match_callstack_filter(machine, stack_trace)) {
> + if (!match_callstack_filter(machine, stack_trace, con->max_stack)) {
> con->nr_filtered += data.count;
> goto next;
> }
> diff --git a/tools/perf/util/lock-contention.c b/tools/perf/util/lock-contention.c
> new file mode 100644
> index 000000000000..841bb18b1f06
> --- /dev/null
> +++ b/tools/perf/util/lock-contention.c
[SNIP]
> +#ifndef HAVE_BPF_SKEL
> +int lock_contention_prepare(struct lock_contention *con __maybe_unused)
> +{
> + return 0;
> +}
> +
> +int lock_contention_start(void)
> +{
> + return 0;
> +}
> +
> +int lock_contention_stop(void)
> +{
> + return 0;
> +}
> +
> +int lock_contention_finish(struct lock_contention *con __maybe_unused)
> +{
> + return 0;
> +}
> +
> +int lock_contention_read(struct lock_contention *con __maybe_unused)
> +{
> + return 0;
> +}
> +#endif /* !HAVE_BPF_SKEL */

Do we really need this part? Why not leave it in the header file?

Thanks,
Namhyung

> diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h
> index 1a7248ff3889..bfa5c7db0a5d 100644
> --- a/tools/perf/util/lock-contention.h
> +++ b/tools/perf/util/lock-contention.h
> @@ -67,10 +67,11 @@ struct lock_stat {
> */
> #define MAX_LOCK_DEPTH 48
>
> -struct lock_stat *lock_stat_find(u64 addr);
> -struct lock_stat *lock_stat_findnew(u64 addr, const char *name, int flags);
> +/* based on kernel/lockdep.c */
> +#define LOCKHASH_BITS 12
> +#define LOCKHASH_SIZE (1UL << LOCKHASH_BITS)
>
> -bool match_callstack_filter(struct machine *machine, u64 *callstack);
> +extern struct hlist_head *lockhash_table;
>
> /*
> * struct lock_seq_stat:
> @@ -148,7 +149,14 @@ struct lock_contention {
> bool save_callstack;
> };
>
> -#ifdef HAVE_BPF_SKEL
> +struct option;
> +int parse_call_stack(const struct option *opt, const char *str, int unset);
> +bool needs_callstack(void);
> +
> +struct lock_stat *lock_stat_find(u64 addr);
> +struct lock_stat *lock_stat_findnew(u64 addr, const char *name, int flags);
> +
> +bool match_callstack_filter(struct machine *machine, u64 *callstack, int max_stack_depth);
>
> int lock_contention_prepare(struct lock_contention *con);
> int lock_contention_start(void);
> @@ -156,25 +164,4 @@ int lock_contention_stop(void);
> int lock_contention_read(struct lock_contention *con);
> int lock_contention_finish(struct lock_contention *con);
>
> -#else /* !HAVE_BPF_SKEL */
> -
> -static inline int lock_contention_prepare(struct lock_contention *con __maybe_unused)
> -{
> - return 0;
> -}
> -
> -static inline int lock_contention_start(void) { return 0; }
> -static inline int lock_contention_stop(void) { return 0; }
> -static inline int lock_contention_finish(struct lock_contention *con __maybe_unused)
> -{
> - return 0;
> -}
> -
> -static inline int lock_contention_read(struct lock_contention *con __maybe_unused)
> -{
> - return 0;
> -}
> -
> -#endif /* HAVE_BPF_SKEL */
> -
> #endif /* PERF_LOCK_CONTENTION_H */
> diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
> index 35d84a96dbec..91fd444615cd 100644
> --- a/tools/perf/util/python.c
> +++ b/tools/perf/util/python.c
> @@ -18,7 +18,6 @@
> #include "mmap.h"
> #include "util/kwork.h"
> #include "util/sample.h"
> -#include "util/lock-contention.h"
> #include <internal/lib.h>
> #include "../builtin.h"
>
> @@ -1311,22 +1310,6 @@ struct kwork_work *perf_kwork_add_work(struct perf_kwork *kwork __maybe_unused,
> return NULL;
> }
>
> -bool match_callstack_filter(struct machine *machine __maybe_unused, u64 *callstack __maybe_unused)
> -{
> - return false;
> -}
> -
> -struct lock_stat *lock_stat_find(u64 addr __maybe_unused)
> -{
> - return NULL;
> -}
> -
> -struct lock_stat *lock_stat_findnew(u64 addr __maybe_unused, const char *name __maybe_unused,
> - int flags __maybe_unused)
> -{
> - return NULL;
> -}
> -
> int cmd_inject(int argc __maybe_unused, const char *argv[] __maybe_unused)
> {
> return -1;
> --
> 2.47.0.rc1.288.g06298d1525-goog
>