From b88635a794661f0359b453190aef1e9ebfdc61d6 Mon Sep 17 00:00:00 2001 From: Yann Droneaud Date: Mon, 30 Jun 2014 22:28:47 +0200 Subject: [PATCH] perf tools: Enable close-on-exec flag on perf file descriptor In commit 35f3ca8474b1 ('perf: Introduce a flag to enable close-on-exec in perf_event_open()'), flag PERF_FLAG_FD_CLOEXEC was added to perf_event_open(2) syscall to allows userspace to atomically enable close-on-exec behavor when creating the file descriptor. This patch makes perf tools use the new flag if supported by the kernel, so that the event file descriptors got automatically closed if perf tool exec a sub-command. Signed-off-by: Yann Droneaud Cc: Andi Kleen Cc: Arnaldo Carvalho de Melo Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Link: http://lkml.kernel.org/n/1404160127-7475-1-git-send-email-ydroneaud@opteya.com Signed-off-by: Jiri Olsa --- tools/perf/Makefile.perf | 1 + tools/perf/bench/mem-memcpy.c | 4 +- tools/perf/bench/mem-memset.c | 4 +- tools/perf/builtin-sched.c | 4 +- tools/perf/tests/bp_signal.c | 4 +- tools/perf/tests/bp_signal_overflow.c | 4 +- tools/perf/tests/rdpmc.c | 4 +- tools/perf/util/cloexec.c | 57 +++++++++++++++++++++++++++ tools/perf/util/cloexec.h | 6 +++ tools/perf/util/evsel.c | 12 ++++-- tools/perf/util/record.c | 9 +++-- 11 files changed, 97 insertions(+), 12 deletions(-) create mode 100644 tools/perf/util/cloexec.c create mode 100644 tools/perf/util/cloexec.h diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index 3308b22a16603..2240974b77458 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -376,6 +376,7 @@ LIB_OBJS += $(OUTPUT)util/record.o LIB_OBJS += $(OUTPUT)util/srcline.o LIB_OBJS += $(OUTPUT)util/data.o LIB_OBJS += $(OUTPUT)util/tsc.o +LIB_OBJS += $(OUTPUT)util/cloexec.o LIB_OBJS += $(OUTPUT)ui/setup.o LIB_OBJS += $(OUTPUT)ui/helpline.o diff --git a/tools/perf/bench/mem-memcpy.c b/tools/perf/bench/mem-memcpy.c index e622c3e96efcc..2465141b554bf 100644 --- a/tools/perf/bench/mem-memcpy.c +++ b/tools/perf/bench/mem-memcpy.c @@ -10,6 +10,7 @@ #include "../util/util.h" #include "../util/parse-options.h" #include "../util/header.h" +#include "../util/cloexec.h" #include "bench.h" #include "mem-memcpy-arch.h" @@ -83,7 +84,8 @@ static struct perf_event_attr cycle_attr = { static void init_cycle(void) { - cycle_fd = sys_perf_event_open(&cycle_attr, getpid(), -1, -1, 0); + cycle_fd = sys_perf_event_open(&cycle_attr, getpid(), -1, -1, + perf_event_open_cloexec_flag()); if (cycle_fd < 0 && errno == ENOSYS) die("No CONFIG_PERF_EVENTS=y kernel support configured?\n"); diff --git a/tools/perf/bench/mem-memset.c b/tools/perf/bench/mem-memset.c index 2a65468619f0f..75fc3e65fb2a8 100644 --- a/tools/perf/bench/mem-memset.c +++ b/tools/perf/bench/mem-memset.c @@ -10,6 +10,7 @@ #include "../util/util.h" #include "../util/parse-options.h" #include "../util/header.h" +#include "../util/cloexec.h" #include "bench.h" #include "mem-memset-arch.h" @@ -83,7 +84,8 @@ static struct perf_event_attr cycle_attr = { static void init_cycle(void) { - cycle_fd = sys_perf_event_open(&cycle_attr, getpid(), -1, -1, 0); + cycle_fd = sys_perf_event_open(&cycle_attr, getpid(), -1, -1, + perf_event_open_cloexec_flag()); if (cycle_fd < 0 && errno == ENOSYS) die("No CONFIG_PERF_EVENTS=y kernel support configured?\n"); diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index b7f555add0c8d..f83c08c0dd87c 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -10,6 +10,7 @@ #include "util/header.h" #include "util/session.h" #include "util/tool.h" +#include "util/cloexec.h" #include "util/parse-options.h" #include "util/trace-event.h" @@ -434,7 +435,8 @@ static int self_open_counters(void) attr.type = PERF_TYPE_SOFTWARE; attr.config = PERF_COUNT_SW_TASK_CLOCK; - fd = sys_perf_event_open(&attr, 0, -1, -1, 0); + fd = sys_perf_event_open(&attr, 0, -1, -1, + perf_event_open_cloexec_flag()); if (fd < 0) pr_err("Error: sys_perf_event_open() syscall returned " diff --git a/tools/perf/tests/bp_signal.c b/tools/perf/tests/bp_signal.c index aba095489193b..a02b035fd5aa8 100644 --- a/tools/perf/tests/bp_signal.c +++ b/tools/perf/tests/bp_signal.c @@ -25,6 +25,7 @@ #include "tests.h" #include "debug.h" #include "perf.h" +#include "cloexec.h" static int fd1; static int fd2; @@ -78,7 +79,8 @@ static int bp_event(void *fn, int setup_signal) pe.exclude_kernel = 1; pe.exclude_hv = 1; - fd = sys_perf_event_open(&pe, 0, -1, -1, 0); + fd = sys_perf_event_open(&pe, 0, -1, -1, + perf_event_open_cloexec_flag()); if (fd < 0) { pr_debug("failed opening event %llx\n", pe.config); return TEST_FAIL; diff --git a/tools/perf/tests/bp_signal_overflow.c b/tools/perf/tests/bp_signal_overflow.c index 44ac82179708b..e765377244918 100644 --- a/tools/perf/tests/bp_signal_overflow.c +++ b/tools/perf/tests/bp_signal_overflow.c @@ -24,6 +24,7 @@ #include "tests.h" #include "debug.h" #include "perf.h" +#include "cloexec.h" static int overflows; @@ -91,7 +92,8 @@ int test__bp_signal_overflow(void) pe.exclude_kernel = 1; pe.exclude_hv = 1; - fd = sys_perf_event_open(&pe, 0, -1, -1, 0); + fd = sys_perf_event_open(&pe, 0, -1, -1, + perf_event_open_cloexec_flag()); if (fd < 0) { pr_debug("failed opening event %llx\n", pe.config); return TEST_FAIL; diff --git a/tools/perf/tests/rdpmc.c b/tools/perf/tests/rdpmc.c index e59143fd9e711..c04d1f2685765 100644 --- a/tools/perf/tests/rdpmc.c +++ b/tools/perf/tests/rdpmc.c @@ -6,6 +6,7 @@ #include "perf.h" #include "debug.h" #include "tests.h" +#include "cloexec.h" #if defined(__x86_64__) || defined(__i386__) @@ -104,7 +105,8 @@ static int __test__rdpmc(void) sa.sa_sigaction = segfault_handler; sigaction(SIGSEGV, &sa, NULL); - fd = sys_perf_event_open(&attr, 0, -1, -1, 0); + fd = sys_perf_event_open(&attr, 0, -1, -1, + perf_event_open_cloexec_flag()); if (fd < 0) { pr_err("Error: sys_perf_event_open() syscall returned " "with %d (%s)\n", fd, strerror(errno)); diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c new file mode 100644 index 0000000000000..c5d05ec172206 --- /dev/null +++ b/tools/perf/util/cloexec.c @@ -0,0 +1,57 @@ +#include "util.h" +#include "../perf.h" +#include "cloexec.h" +#include "asm/bug.h" + +static unsigned long flag = PERF_FLAG_FD_CLOEXEC; + +static int perf_flag_probe(void) +{ + /* use 'safest' configuration as used in perf_evsel__fallback() */ + struct perf_event_attr attr = { + .type = PERF_COUNT_SW_CPU_CLOCK, + .config = PERF_COUNT_SW_CPU_CLOCK, + }; + int fd; + int err; + + /* check cloexec flag */ + fd = sys_perf_event_open(&attr, 0, -1, -1, + PERF_FLAG_FD_CLOEXEC); + err = errno; + + if (fd >= 0) { + close(fd); + return 1; + } + + WARN_ONCE(err != EINVAL, + "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", + err, strerror(err)); + + /* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */ + fd = sys_perf_event_open(&attr, 0, -1, -1, 0); + err = errno; + + if (WARN_ONCE(fd < 0, + "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", + err, strerror(err))) + return -1; + + close(fd); + + return 0; +} + +unsigned long perf_event_open_cloexec_flag(void) +{ + static bool probed; + + if (!probed) { + if (perf_flag_probe() <= 0) + flag = 0; + probed = true; + } + + return flag; +} diff --git a/tools/perf/util/cloexec.h b/tools/perf/util/cloexec.h new file mode 100644 index 0000000000000..94a5a7d829d5b --- /dev/null +++ b/tools/perf/util/cloexec.h @@ -0,0 +1,6 @@ +#ifndef __PERF_CLOEXEC_H +#define __PERF_CLOEXEC_H + +unsigned long perf_event_open_cloexec_flag(void); + +#endif /* __PERF_CLOEXEC_H */ diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 90f58cdd0fb08..21a373ebea226 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -29,6 +29,7 @@ static struct { bool sample_id_all; bool exclude_guest; bool mmap2; + bool cloexec; } perf_missing_features; #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y)) @@ -994,7 +995,7 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, struct thread_map *threads) { int cpu, thread; - unsigned long flags = 0; + unsigned long flags = PERF_FLAG_FD_CLOEXEC; int pid = -1, err; enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE; @@ -1003,11 +1004,13 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, return -ENOMEM; if (evsel->cgrp) { - flags = PERF_FLAG_PID_CGROUP; + flags |= PERF_FLAG_PID_CGROUP; pid = evsel->cgrp->fd; } fallback_missing_features: + if (perf_missing_features.cloexec) + flags &= ~(unsigned long)PERF_FLAG_FD_CLOEXEC; if (perf_missing_features.mmap2) evsel->attr.mmap2 = 0; if (perf_missing_features.exclude_guest) @@ -1076,7 +1079,10 @@ try_fallback: if (err != -EINVAL || cpu > 0 || thread > 0) goto out_close; - if (!perf_missing_features.mmap2 && evsel->attr.mmap2) { + if (!perf_missing_features.cloexec && (flags & PERF_FLAG_FD_CLOEXEC)) { + perf_missing_features.cloexec = true; + goto fallback_missing_features; + } else if (!perf_missing_features.mmap2 && evsel->attr.mmap2) { perf_missing_features.mmap2 = true; goto fallback_missing_features; } else if (!perf_missing_features.exclude_guest && diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c index 165723152cfb6..fe8079edbdc11 100644 --- a/tools/perf/util/record.c +++ b/tools/perf/util/record.c @@ -4,6 +4,7 @@ #include "parse-events.h" #include #include "util.h" +#include "cloexec.h" typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel); @@ -11,6 +12,7 @@ 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; evlist = perf_evlist__new(); @@ -22,14 +24,14 @@ static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str) evsel = perf_evlist__first(evlist); - fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, 0); + fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, flags); if (fd < 0) goto out_delete; close(fd); fn(evsel); - fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, 0); + fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, flags); if (fd < 0) { if (errno == EINVAL) err = -EINVAL; @@ -219,7 +221,8 @@ bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str) cpu = evlist->cpus->map[0]; } - fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, 0); + fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, + perf_event_open_cloexec_flag()); if (fd >= 0) { close(fd); ret = true; -- 2.39.5