perf tools: Enable close-on-exec flag on perf file descriptor
In commit a21b0b354d4a ('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 <ydroneaud@opteya.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/1404160127-7475-1-git-send-email-ydroneaud@opteya.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 90f58cd..21a373e 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -29,6 +29,7 @@
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 @@
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 @@
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 @@
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 &&
