#include "evlist.h"
#include "evsel.h"
#include "cpumap.h"
#include "parse-events.h"
#include <api/fs/fs.h>
#include "util.h"
#include "cloexec.h"

typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);

static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
{
	struct perf_evlist *evlist;
	struct perf_evsel *evsel;
	unsigned long flags = perf_event_open_cloexec_flag();
	int err = -EAGAIN, fd;
	static pid_t pid = -1;

	evlist = perf_evlist__new();
	if (!evlist)
		return -ENOMEM;

	if (parse_events(evlist, str, NULL))
		goto out_delete;

	evsel = perf_evlist__first(evlist);

	while (1) {
		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
		if (fd < 0) {
			if (pid == -1 && errno == EACCES) {
				pid = 0;
				continue;
			}
			goto out_delete;
		}
		break;
	}
	close(fd);

	fn(evsel);

	fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
	if (fd < 0) {
		if (errno == EINVAL)
			err = -EINVAL;
		goto out_delete;
	}
	close(fd);
	err = 0;

out_delete:
	perf_evlist__delete(evlist);
	return err;
}

static bool perf_probe_api(setup_probe_fn_t fn)
{
	const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};
	struct cpu_map *cpus;
	int cpu, ret, i = 0;

	cpus = cpu_map__new(NULL);
	if (!cpus)
		return false;
	cpu = cpus->map[0];
	cpu_map__put(cpus);

	do {
		ret = perf_do_probe_api(fn, cpu, try[i++]);
		if (!ret)
			return true;
	} while (ret == -EAGAIN && try[i]);

	return false;
}

static void perf_probe_sample_identifier(struct perf_evsel *evsel)
{
	evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
}

static void perf_probe_comm_exec(struct perf_evsel *evsel)
{
	evsel->attr.comm_exec = 1;
}

static void perf_probe_context_switch(struct perf_evsel *evsel)
{
	evsel->attr.context_switch = 1;
}

bool perf_can_sample_identifier(void)
{
	return perf_probe_api(perf_probe_sample_identifier);
}

static bool perf_can_comm_exec(void)
{
	return perf_probe_api(perf_probe_comm_exec);
}

bool perf_can_record_switch_events(void)
{
	return perf_probe_api(perf_probe_context_switch);
}

bool perf_can_record_cpu_wide(void)
{
	struct perf_event_attr attr = {
		.type = PERF_TYPE_SOFTWARE,
		.config = PERF_COUNT_SW_CPU_CLOCK,
		.exclude_kernel = 1,
	};
	struct cpu_map *cpus;
	int cpu, fd;

	cpus = cpu_map__new(NULL);
	if (!cpus)
		return false;
	cpu = cpus->map[0];
	cpu_map__put(cpus);

	fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
	if (fd < 0)
		return false;
	close(fd);

	return true;
}

void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
			 struct callchain_param *callchain)
{
	struct perf_evsel *evsel;
	bool use_sample_identifier = false;
	bool use_comm_exec;

	/*
	 * Set the evsel leader links before we configure attributes,
	 * since some might depend on this info.
	 */
	if (opts->group)
		perf_evlist__set_leader(evlist);

	if (evlist->cpus->map[0] < 0)
		opts->no_inherit = true;

	use_comm_exec = perf_can_comm_exec();

	evlist__for_each_entry(evlist, evsel) {
		perf_evsel__config(evsel, opts, callchain);
		if (evsel->tracking && use_comm_exec)
			evsel->attr.comm_exec = 1;
	}

	if (opts->full_auxtrace) {
		/*
		 * Need to be able to synthesize and parse selected events with
		 * arbitrary sample types, which requires always being able to
		 * match the id.
		 */
		use_sample_identifier = perf_can_sample_identifier();
		evlist__for_each_entry(evlist, evsel)
			perf_evsel__set_sample_id(evsel, use_sample_identifier);
	} else if (evlist->nr_entries > 1) {
		struct perf_evsel *first = perf_evlist__first(evlist);

		evlist__for_each_entry(evlist, evsel) {
			if (evsel->attr.sample_type == first->attr.sample_type)
				continue;
			use_sample_identifier = perf_can_sample_identifier();
			break;
		}
		evlist__for_each_entry(evlist, evsel)
			perf_evsel__set_sample_id(evsel, use_sample_identifier);
	}

	perf_evlist__set_id_pos(evlist);
}

static int get_max_rate(unsigned int *rate)
{
	return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
}

static int record_opts__config_freq(struct record_opts *opts)
{
	bool user_freq = opts->user_freq != UINT_MAX;
	unsigned int max_rate;

	if (opts->user_interval != ULLONG_MAX)
		opts->default_interval = opts->user_interval;
	if (user_freq)
		opts->freq = opts->user_freq;

	/*
	 * User specified count overrides default frequency.
	 */
	if (opts->default_interval)
		opts->freq = 0;
	else if (opts->freq) {
		opts->default_interval = opts->freq;
	} else {
		pr_err("frequency and count are zero, aborting\n");
		return -1;
	}

	if (get_max_rate(&max_rate))
		return 0;

	/*
	 * User specified frequency is over current maximum.
	 */
	if (user_freq && (max_rate < opts->freq)) {
		pr_err("Maximum frequency rate (%u) reached.\n"
		   "Please use -F freq option with lower value or consider\n"
		   "tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
		   max_rate);
		return -1;
	}

	/*
	 * Default frequency is over current maximum.
	 */
	if (max_rate < opts->freq) {
		pr_warning("Lowering default frequency rate to %u.\n"
			   "Please consider tweaking "
			   "/proc/sys/kernel/perf_event_max_sample_rate.\n",
			   max_rate);
		opts->freq = max_rate;
	}

	return 0;
}

int record_opts__config(struct record_opts *opts)
{
	return record_opts__config_freq(opts);
}

bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str)
{
	struct perf_evlist *temp_evlist;
	struct perf_evsel *evsel;
	int err, fd, cpu;
	bool ret = false;
	pid_t pid = -1;

	temp_evlist = perf_evlist__new();
	if (!temp_evlist)
		return false;

	err = parse_events(temp_evlist, str, NULL);
	if (err)
		goto out_delete;

	evsel = perf_evlist__last(temp_evlist);

	if (!evlist || cpu_map__empty(evlist->cpus)) {
		struct cpu_map *cpus = cpu_map__new(NULL);

		cpu =  cpus ? cpus->map[0] : 0;
		cpu_map__put(cpus);
	} else {
		cpu = evlist->cpus->map[0];
	}

	while (1) {
		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1,
					 perf_event_open_cloexec_flag());
		if (fd < 0) {
			if (pid == -1 && errno == EACCES) {
				pid = 0;
				continue;
			}
			goto out_delete;
		}
		break;
	}
	close(fd);
	ret = true;

out_delete:
	perf_evlist__delete(temp_evlist);
	return ret;
}
rt of the tracer. It is
pinned to a single CPU and will move to the next CPU after each period of
running. If the user modifies the migration thread's affinity, it will not
change after that happens.

The original code created the thread at the first instance it was called,
but later was changed to destroy the thread after the tracer was finished,
and would not be created until the next instance of the tracer was
established. The code that initialized the affinity was only called on the
initial instantiation of the tracer. After that, it was not initialized, and
the previous affinity did not match the current newly created one, making
it appear that the user modified the thread's affinity when it did not, and
the thread failed to migrate again.

Cc: stable@vger.kernel.org
Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>Diffstat</a> (limited to 'drivers/usb/host/ehci-q.c')</div><table summary='diffstat' class='diffstat'>