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authorArnaldo Carvalho de Melo <acme@redhat.com>2018-11-21 17:42:00 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-11-21 22:25:44 -0300
commit11c6cbe706f218a8dc7e1f962f12b3a52ddd33a9 (patch)
tree447b75de74aabf184590ef63aeae5773e96a39e0 /tools/build/feature
parentd47d77c3f008d3cf02c6ce92ef4f6e32ca270351 (diff)
downloadlinux-11c6cbe706f218a8dc7e1f962f12b3a52ddd33a9.tar.bz2
tools build feature: Check if eventfd() is available
A new 'perf bench epoll' will use this, and to disable it for older systems, add a feature test for this API. This is just a simple program that if successfully compiled, means that the feature is present, at least at the library level, in a build that sets the output directory to /tmp/build/perf (using O=/tmp/build/perf), we end up with: $ ls -la /tmp/build/perf/feature/test-eventfd* -rwxrwxr-x. 1 acme acme 8176 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.bin -rw-rw-r--. 1 acme acme 588 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.d -rw-rw-r--. 1 acme acme 0 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.make.output $ ldd /tmp/build/perf/feature/test-eventfd.bin linux-vdso.so.1 (0x00007fff3bf3f000) libc.so.6 => /lib64/libc.so.6 (0x00007fa984061000) /lib64/ld-linux-x86-64.so.2 (0x00007fa984417000) $ grep eventfd -A 2 -B 2 /tmp/build/perf/FEATURE-DUMP feature-dwarf=1 feature-dwarf_getlocations=1 feature-eventfd=1 feature-fortify-source=1 feature-sync-compare-and-swap=1 $ The main thing here is that in the end we'll have -DHAVE_EVENTFD in CFLAGS, and then the 'perf bench' entry needing that API can be selectively pruned. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Ahern <dsahern@gmail.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Jason Baron <jbaron@akamai.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-wkeldwob7dpx6jvtuzl8164k@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/build/feature')
-rw-r--r--tools/build/feature/Makefile4
-rw-r--r--tools/build/feature/test-all.c5
-rw-r--r--tools/build/feature/test-eventfd.c9
3 files changed, 18 insertions, 0 deletions
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 304b984f11b9..325087a0429c 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -5,6 +5,7 @@ FILES= \
test-bionic.bin \
test-dwarf.bin \
test-dwarf_getlocations.bin \
+ test-eventfd.bin \
test-fortify-source.bin \
test-sync-compare-and-swap.bin \
test-get_current_dir_name.bin \
@@ -102,6 +103,9 @@ $(OUTPUT)test-bionic.bin:
$(OUTPUT)test-libelf.bin:
$(BUILD) -lelf
+$(OUTPUT)test-eventfd.bin:
+ $(BUILD)
+
$(OUTPUT)test-get_current_dir_name.bin:
$(BUILD)
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index 56722bfe6bdd..58f01b950195 100644
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -50,6 +50,10 @@
# include "test-dwarf_getlocations.c"
#undef main
+#define main main_test_eventfd
+# include "test-eventfd.c"
+#undef main
+
#define main main_test_libelf_getphdrnum
# include "test-libelf-getphdrnum.c"
#undef main
@@ -182,6 +186,7 @@ int main(int argc, char *argv[])
main_test_glibc();
main_test_dwarf();
main_test_dwarf_getlocations();
+ main_test_eventfd();
main_test_libelf_getphdrnum();
main_test_libelf_gelf_getnote();
main_test_libelf_getshdrstrndx();
diff --git a/tools/build/feature/test-eventfd.c b/tools/build/feature/test-eventfd.c
new file mode 100644
index 000000000000..f4de7ef00ccb
--- /dev/null
+++ b/tools/build/feature/test-eventfd.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
+
+#include <sys/eventfd.h>
+
+int main(void)
+{
+ return eventfd(0, EFD_NONBLOCK);
+}