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// SPDX-License-Identifier: GPL-2.0
#include "util/debug.h"
#include "util/evlist.h"
#include "util/machine.h"
#include "util/map.h"
#include "util/symbol.h"
#include "util/target.h"
#include "util/thread.h"
#include "util/thread_map.h"
#include "util/lock-contention.h"
#include <linux/zalloc.h>
#include <linux/string.h>
#include <bpf/bpf.h>
#include "bpf_skel/lock_contention.skel.h"
#include "bpf_skel/lock_data.h"
static struct lock_contention_bpf *skel;
int lock_contention_prepare(struct lock_contention *con)
{
int i, fd;
int ncpus = 1, ntasks = 1;
struct evlist *evlist = con->evlist;
struct target *target = con->target;
skel = lock_contention_bpf__open();
if (!skel) {
pr_err("Failed to open lock-contention BPF skeleton\n");
return -1;
}
bpf_map__set_value_size(skel->maps.stacks, con->max_stack * sizeof(u64));
bpf_map__set_max_entries(skel->maps.lock_stat, con->map_nr_entries);
bpf_map__set_max_entries(skel->maps.tstamp, con->map_nr_entries);
if (con->aggr_mode == LOCK_AGGR_TASK) {
bpf_map__set_max_entries(skel->maps.task_data, con->map_nr_entries);
bpf_map__set_max_entries(skel->maps.stacks, 1);
} else {
bpf_map__set_max_entries(skel->maps.task_data, 1);
bpf_map__set_max_entries(skel->maps.stacks, con->map_nr_entries);
}
if (target__has_cpu(target))
ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
if (target__has_task(target))
ntasks = perf_thread_map__nr(evlist->core.threads);
bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
if (lock_contention_bpf__load(skel) < 0) {
pr_err("Failed to load lock-contention BPF skeleton\n");
return -1;
}
if (target__has_cpu(target)) {
u32 cpu;
u8 val = 1;
skel->bss->has_cpu = 1;
fd = bpf_map__fd(skel->maps.cpu_filter);
for (i = 0; i < ncpus; i++) {
cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu;
bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
}
}
if (target__has_task(target)) {
u32 pid;
u8 val = 1;
skel->bss->has_task = 1;
fd = bpf_map__fd(skel->maps.task_filter);
for (i = 0; i < ntasks; i++) {
pid = perf_thread_map__pid(evlist->core.threads, i);
bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
}
}
if (target__none(target) && evlist->workload.pid > 0) {
u32 pid = evlist->workload.pid;
u8 val = 1;
skel->bss->has_task = 1;
fd = bpf_map__fd(skel->maps.task_filter);
bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
}
/* these don't work well if in the rodata section */
skel->bss->stack_skip = con->stack_skip;
skel->bss->aggr_mode = con->aggr_mode;
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 lock_contention *con)
{
int fd, stack, task_fd, err = 0;
struct contention_key *prev_key, key;
struct contention_data data = {};
struct lock_stat *st = NULL;
struct machine *machine = con->machine;
u64 *stack_trace;
size_t stack_size = con->max_stack * sizeof(*stack_trace);
fd = bpf_map__fd(skel->maps.lock_stat);
stack = bpf_map__fd(skel->maps.stacks);
task_fd = bpf_map__fd(skel->maps.task_data);
con->lost = skel->bss->lost;
stack_trace = zalloc(stack_size);
if (stack_trace == NULL)
return -1;
if (con->aggr_mode == LOCK_AGGR_TASK) {
struct thread *idle = __machine__findnew_thread(machine,
/*pid=*/0,
/*tid=*/0);
thread__set_comm(idle, "swapper", /*timestamp=*/0);
}
/* make sure it loads the kernel map */
map__load(maps__first(machine->kmaps));
prev_key = NULL;
while (!bpf_map_get_next_key(fd, prev_key, &key)) {
struct map *kmap;
struct symbol *sym;
int idx = 0;
s32 stack_id;
/* to handle errors in the loop body */
err = -1;
bpf_map_lookup_elem(fd, &key, &data);
st = zalloc(sizeof(*st));
if (st == NULL)
break;
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;
st->addr = key.aggr_key;
if (con->aggr_mode == LOCK_AGGR_TASK) {
struct contention_task_data task;
struct thread *t;
int pid = key.aggr_key;
/* do not update idle comm which contains CPU number */
if (st->addr) {
bpf_map_lookup_elem(task_fd, &pid, &task);
t = __machine__findnew_thread(machine, /*pid=*/-1, pid);
thread__set_comm(t, task.comm, /*timestamp=*/0);
}
goto next;
}
if (con->aggr_mode == LOCK_AGGR_ADDR) {
sym = machine__find_kernel_symbol(machine, st->addr, &kmap);
if (sym)
st->name = strdup(sym->name);
goto next;
}
stack_id = key.aggr_key;
bpf_map_lookup_elem(stack, &stack_id, stack_trace);
/* skip lock internal functions */
while (machine__is_lock_function(machine, stack_trace[idx]) &&
idx < con->max_stack - 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)
break;
} else if (asprintf(&st->name, "%#lx", (unsigned long)st->addr) < 0) {
break;
}
if (verbose) {
st->callstack = memdup(stack_trace, stack_size);
if (st->callstack == NULL)
break;
}
next:
hlist_add_head(&st->hash_entry, con->result);
prev_key = &key;
/* we're fine now, reset the values */
st = NULL;
err = 0;
}
free(stack_trace);
if (st) {
free(st->name);
free(st);
}
return err;
}
int lock_contention_finish(void)
{
if (skel) {
skel->bss->enabled = 0;
lock_contention_bpf__destroy(skel);
}
return 0;
}
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