cache kernelVersion(), make isAtLeastKernelVersion() cheaper
not perfect due to this being in a header file, so multiple copies
potentially exist, but it's really simple, and works nearly as well.
Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Id90c6933d57bc12f4dd640c8918fd0885c7474cf
diff --git a/staticlibs/native/bpf_headers/include/bpf/BpfUtils.h b/staticlibs/native/bpf_headers/include/bpf/BpfUtils.h
index 8f1b9a2..7801c3e 100644
--- a/staticlibs/native/bpf_headers/include/bpf/BpfUtils.h
+++ b/staticlibs/native/bpf_headers/include/bpf/BpfUtils.h
@@ -92,7 +92,7 @@
#define KVER(a, b, c) (((a) << 24) + ((b) << 16) + (c))
-static inline unsigned kernelVersion() {
+static inline unsigned uncachedKernelVersion() {
struct utsname buf;
int ret = uname(&buf);
if (ret) return 0;
@@ -108,6 +108,11 @@
return KVER(kver_major, kver_minor, kver_sub);
}
+static inline unsigned kernelVersion() {
+ static unsigned kver = uncachedKernelVersion();
+ return kver;
+}
+
static inline bool isAtLeastKernelVersion(unsigned major, unsigned minor, unsigned sub) {
return kernelVersion() >= KVER(major, minor, sub);
}
diff --git a/staticlibs/native/tcutils/kernelversion.h b/staticlibs/native/tcutils/kernelversion.h
index 3be1ad2..492444a 100644
--- a/staticlibs/native/tcutils/kernelversion.h
+++ b/staticlibs/native/tcutils/kernelversion.h
@@ -32,7 +32,7 @@
namespace android {
-static inline unsigned kernelVersion() {
+static inline unsigned uncachedKernelVersion() {
struct utsname buf;
int ret = uname(&buf);
if (ret)
@@ -51,6 +51,11 @@
return KVER(kver_major, kver_minor, kver_sub);
}
+static unsigned kernelVersion() {
+ static unsigned kver = uncachedKernelVersion();
+ return kver;
+}
+
static inline bool isAtLeastKernelVersion(unsigned major, unsigned minor,
unsigned sub) {
return kernelVersion() >= KVER(major, minor, sub);