This is to filter lock contention from specific slab objects only. Like in the lock symbol output, we can use '&' prefix to filter slab object names. root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -abl sleep 1 contended total wait max wait avg wait address symbol 3 14.99 us 14.44 us 5.00 us ffffffff851c0940 pack_mutex (mutex) 2 2.75 us 2.56 us 1.38 us ffff98d7031fb498 &task_struct (mutex) 4 1.42 us 557 ns 355 ns ffff98d706311400 &kmalloc-cg-512 (mutex) 2 953 ns 714 ns 476 ns ffffffff851c3620 delayed_uprobe_lock (mutex) 1 929 ns 929 ns 929 ns ffff98d7031fb538 &task_struct (mutex) 3 561 ns 210 ns 187 ns ffffffff84a8b3a0 text_mutex (mutex) 1 479 ns 479 ns 479 ns ffffffff851b4cf8 tracepoint_srcu_srcu_usage (mutex) 2 320 ns 195 ns 160 ns ffffffff851cf840 pcpu_alloc_mutex (mutex) 1 212 ns 212 ns 212 ns ffff98d7031784d8 &signal_cache (mutex) 1 177 ns 177 ns 177 ns ffffffff851b4c28 tracepoint_srcu_srcu_usage (mutex) With the filter, it can show contentions from the task_struct only. root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -abl -L '&task_struct' sleep 1 contended total wait max wait avg wait address symbol 2 1.97 us 1.71 us 987 ns ffff98d7032fd658 &task_struct (mutex) 1 1.20 us 1.20 us 1.20 us ffff98d7032fd6f8 &task_struct (mutex) It can work with other aggregation mode: root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -ab -L '&task_struct' sleep 1 contended total wait max wait avg wait type caller 1 25.10 us 25.10 us 25.10 us mutex perf_event_exit_task+0x39 1 21.60 us 21.60 us 21.60 us mutex futex_exit_release+0x21 1 5.56 us 5.56 us 5.56 us mutex futex_exec_release+0x21 Acked-by: Ian Rogers <irogers@xxxxxxxxxx> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx> --- tools/perf/builtin-lock.c | 35 ++++++++++++++++ tools/perf/util/bpf_lock_contention.c | 40 ++++++++++++++++++- .../perf/util/bpf_skel/lock_contention.bpf.c | 21 +++++++++- tools/perf/util/lock-contention.h | 2 + 4 files changed, 95 insertions(+), 3 deletions(-) diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c index d9f3477d2b02b612..208c482daa56ef93 100644 --- a/tools/perf/builtin-lock.c +++ b/tools/perf/builtin-lock.c @@ -1539,6 +1539,12 @@ static void lock_filter_finish(void) zfree(&filters.cgrps); filters.nr_cgrps = 0; + + for (int i = 0; i < filters.nr_slabs; i++) + free(filters.slabs[i]); + + zfree(&filters.slabs); + filters.nr_slabs = 0; } static void sort_contention_result(void) @@ -2305,6 +2311,27 @@ static bool add_lock_sym(char *name) return true; } +static bool add_lock_slab(char *name) +{ + char **tmp; + char *sym = strdup(name); + + if (sym == NULL) { + pr_err("Memory allocation failure\n"); + return false; + } + + tmp = realloc(filters.slabs, (filters.nr_slabs + 1) * sizeof(*filters.slabs)); + if (tmp == NULL) { + pr_err("Memory allocation failure\n"); + return false; + } + + tmp[filters.nr_slabs++] = sym; + filters.slabs = tmp; + return true; +} + static int parse_lock_addr(const struct option *opt __maybe_unused, const char *str, int unset __maybe_unused) { @@ -2328,6 +2355,14 @@ static int parse_lock_addr(const struct option *opt __maybe_unused, const char * continue; } + if (*tok == '&') { + if (!add_lock_slab(tok + 1)) { + ret = -1; + break; + } + continue; + } + /* * At this moment, we don't have kernel symbols. Save the symbols * in a separate list and resolve them to addresses later. diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c index a31ace04cb5e7a8f..fc8666222399c995 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -112,7 +112,7 @@ static void exit_slab_cache_iter(void) int lock_contention_prepare(struct lock_contention *con) { int i, fd; - int ncpus = 1, ntasks = 1, ntypes = 1, naddrs = 1, ncgrps = 1; + int ncpus = 1, ntasks = 1, ntypes = 1, naddrs = 1, ncgrps = 1, nslabs = 1; struct evlist *evlist = con->evlist; struct target *target = con->target; @@ -201,6 +201,13 @@ int lock_contention_prepare(struct lock_contention *con) check_slab_cache_iter(con); + if (con->filters->nr_slabs && has_slab_iter) { + skel->rodata->has_slab = 1; + nslabs = con->filters->nr_slabs; + } + + bpf_map__set_max_entries(skel->maps.slab_filter, nslabs); + if (lock_contention_bpf__load(skel) < 0) { pr_err("Failed to load lock-contention BPF skeleton\n"); return -1; @@ -271,6 +278,36 @@ int lock_contention_prepare(struct lock_contention *con) bpf_program__set_autoload(skel->progs.collect_lock_syms, false); lock_contention_bpf__attach(skel); + + /* run the slab iterator after attaching */ + run_slab_cache_iter(); + + if (con->filters->nr_slabs) { + u8 val = 1; + int cache_fd; + long key, *prev_key; + + fd = bpf_map__fd(skel->maps.slab_filter); + + /* Read the slab cache map and build a hash with its address */ + cache_fd = bpf_map__fd(skel->maps.slab_caches); + prev_key = NULL; + while (!bpf_map_get_next_key(cache_fd, prev_key, &key)) { + struct slab_cache_data data; + + if (bpf_map_lookup_elem(cache_fd, &key, &data) < 0) + break; + + for (i = 0; i < con->filters->nr_slabs; i++) { + if (!strcmp(con->filters->slabs[i], data.name)) { + bpf_map_update_elem(fd, &key, &val, BPF_ANY); + break; + } + } + prev_key = &key; + } + } + return 0; } @@ -396,7 +433,6 @@ static void account_end_timestamp(struct lock_contention *con) int lock_contention_start(void) { - run_slab_cache_iter(); skel->bss->enabled = 1; return 0; } diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c index 7182eb559496e34e..6c771ef751d83b43 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -100,6 +100,13 @@ struct { __uint(max_entries, 1); } cgroup_filter SEC(".maps"); +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(key_size, sizeof(long)); + __uint(value_size, sizeof(__u8)); + __uint(max_entries, 1); +} slab_filter SEC(".maps"); + struct { __uint(type, BPF_MAP_TYPE_HASH); __uint(key_size, sizeof(long)); @@ -131,6 +138,7 @@ const volatile int has_task; const volatile int has_type; const volatile int has_addr; const volatile int has_cgroup; +const volatile int has_slab; const volatile int needs_callstack; const volatile int stack_skip; const volatile int lock_owner; @@ -213,7 +221,7 @@ static inline int can_record(u64 *ctx) __u64 addr = ctx[0]; ok = bpf_map_lookup_elem(&addr_filter, &addr); - if (!ok) + if (!ok && !has_slab) return 0; } @@ -226,6 +234,17 @@ static inline int can_record(u64 *ctx) return 0; } + if (has_slab && bpf_get_kmem_cache) { + __u8 *ok; + __u64 addr = ctx[0]; + long kmem_cache_addr; + + kmem_cache_addr = (long)bpf_get_kmem_cache(addr); + ok = bpf_map_lookup_elem(&slab_filter, &kmem_cache_addr); + if (!ok) + return 0; + } + return 1; } diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h index bd71fb73825aa8e1..a09f7fe877df8184 100644 --- a/tools/perf/util/lock-contention.h +++ b/tools/perf/util/lock-contention.h @@ -10,10 +10,12 @@ struct lock_filter { int nr_addrs; int nr_syms; int nr_cgrps; + int nr_slabs; unsigned int *types; unsigned long *addrs; char **syms; u64 *cgrps; + char **slabs; }; struct lock_stat { -- 2.47.1.613.gc27f4b7a9f-goog