// SPDX-License-Identifier: GPL-2.0 #include "util/debug.h" #include "util/machine.h" #include "util/map.h" #include "util/symbol.h" #include "util/lock-contention.h" #include <linux/zalloc.h> #include <bpf/bpf.h> #include "bpf_skel/lock_contention.skel.h" static struct lock_contention_bpf *skel; /* should be same as bpf_skel/lock_contention.bpf.c */ struct lock_contention_key { u32 stack_id; }; struct lock_contention_data { u64 total_time; u64 min_time; u64 max_time; u32 count; u32 flags; }; int lock_contention_prepare(void) { skel = lock_contention_bpf__open(); if (!skel) { pr_err("Failed to open lock-contention BPF skeleton\n"); return -1; } if (lock_contention_bpf__load(skel) < 0) { pr_err("Failed to load lock-contention BPF skeleton\n"); return -1; } lock_contention_bpf__attach(skel); return 0; } int lock_contention_start(void) { skel->bss->enabled = 1; return 0; } int lock_contention_stop(void) { skel->bss->enabled = 0; return 0; } int lock_contention_read(struct machine *machine, struct hlist_head *head) { int fd, stack; u32 prev_key, key; struct lock_contention_data data; struct lock_stat *st; u64 stack_trace[CONTENTION_STACK_DEPTH]; fd = bpf_map__fd(skel->maps.lock_stat); stack = bpf_map__fd(skel->maps.stacks); prev_key = 0; while (!bpf_map_get_next_key(fd, &prev_key, &key)) { struct map *kmap; struct symbol *sym; int idx; bpf_map_lookup_elem(fd, &key, &data); st = zalloc(sizeof(*st)); if (st == NULL) return -1; st->nr_contended = data.count; st->wait_time_total = data.total_time; st->wait_time_max = data.max_time; st->wait_time_min = data.min_time; if (data.count) st->avg_wait_time = data.total_time / data.count; st->flags = data.flags; bpf_map_lookup_elem(stack, &key, stack_trace); /* skip BPF + lock internal functions */ idx = CONTENTION_STACK_SKIP; while (is_lock_function(machine, stack_trace[idx]) && idx < CONTENTION_STACK_DEPTH - 1) idx++; st->addr = stack_trace[idx]; sym = machine__find_kernel_symbol(machine, st->addr, &kmap); if (sym) { unsigned long offset; int ret = 0; offset = kmap->map_ip(kmap, st->addr) - sym->start; if (offset) ret = asprintf(&st->name, "%s+%#lx", sym->name, offset); else st->name = strdup(sym->name); if (ret < 0 || st->name == NULL) return -1; } else if (asprintf(&st->name, "%#lx", (unsigned long)st->addr) < 0) { free(st); return -1; } hlist_add_head(&st->hash_entry, head); prev_key = key; } return 0; } int lock_contention_finish(void) { if (skel) { skel->bss->enabled = 0; lock_contention_bpf__destroy(skel); } return 0; }