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Subject[PATCH] perf tools: rework of handling lack of sched_getcpu in old glibc
Date
Commit e1e455f4f4d3 ("perf tools: Work around lack of sched_getcpu in
glibc < 2.6.") introduced weak function sched_getcpu() which should
be overridden by sched_getcpu() provided by glibc >= 2.6. Unfortunately,
the weak function was linked to sched_getcpu() used in perf bench numa
and made the benchmark heavily relying on this function unusable.

This patch alternates weak function magic for preprocessor defines.

Signed-off-by: Petr Holasek <pholasek@redhat.com>
---
tools/perf/util/cloexec.c | 13 +++++++++++--
tools/perf/util/cloexec.h | 6 ------
2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
index 85b5238..23b8aa9 100644
--- a/tools/perf/util/cloexec.c
+++ b/tools/perf/util/cloexec.c
@@ -7,11 +7,20 @@

static unsigned long flag = PERF_FLAG_FD_CLOEXEC;

-int __weak sched_getcpu(void)
+#ifdef __GLIBC_PREREQ
+#if !__GLIBC_PREREQ(2, 6)
+static int do_sched_getcpu(void)
{
errno = ENOSYS;
return -1;
}
+#else
+static int do_sched_getcpu(void)
+{
+ return sched_getcpu();
+}
+#endif
+#endif

static int perf_flag_probe(void)
{
@@ -27,7 +36,7 @@ static int perf_flag_probe(void)
pid_t pid = -1;
char sbuf[STRERR_BUFSIZE];

- cpu = sched_getcpu();
+ cpu = do_sched_getcpu();
if (cpu < 0)
cpu = 0;

diff --git a/tools/perf/util/cloexec.h b/tools/perf/util/cloexec.h
index 68888c2..94a5a7d 100644
--- a/tools/perf/util/cloexec.h
+++ b/tools/perf/util/cloexec.h
@@ -3,10 +3,4 @@

unsigned long perf_event_open_cloexec_flag(void);

-#ifdef __GLIBC_PREREQ
-#if !__GLIBC_PREREQ(2, 6)
-extern int sched_getcpu(void) __THROW;
-#endif
-#endif
-
#endif /* __PERF_CLOEXEC_H */
--
2.1.0


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