bionic_systrace: moving global static variables
Some global static variables are only used within a single function,
so moving them inside the function which requires them. This also
ensures those static variables of class types are initialized before
they are being used.
For example, this is needed for CachedProperty(), as some of the
member method, e.g., CachedProperty().Get(), might be invoked,
e.g., in __libc_preinit(), before the constructor is invoked.
This happens after we added property trace points in commit
Id2b93acb2ce02b308c0e4889f836159151af3b46.
For g_lock, we don't move them because it can be initialized by setting
its memory to 0. And it's used in two functions.
https://android.googlesource.com/platform/bionic/+/refs/heads/master/libc/private/bionic_lock.h
Bug: 147275573
Test: atest CtsBionicTestCases
Test: adb shell perfetto -o /data/misc/perfetto-traces/test_trace -t 10s bionic sysprop
Change-Id: I99565ce2442d34f33830778915c737eed834f8b3
diff --git a/libc/bionic/bionic_systrace.cpp b/libc/bionic/bionic_systrace.cpp
index 06f4505..0de51c5 100644
--- a/libc/bionic/bionic_systrace.cpp
+++ b/libc/bionic/bionic_systrace.cpp
@@ -31,33 +31,29 @@
#define WRITE_OFFSET 32
static Lock g_lock;
-static uint64_t g_tags;
-static int g_trace_marker_fd = -1;
-
-static CachedProperty& GetTagsProp() {
- static CachedProperty cached_property(kTraceTagsProp);
- return cached_property;
-}
bool should_trace(const uint64_t enable_tags) {
+ static uint64_t tags_val;
+ static CachedProperty tags_prop(kTraceTagsProp);
g_lock.lock();
- if (GetTagsProp().DidChange()) {
- g_tags = strtoull(GetTagsProp().Get(), nullptr, 0);
+ if (tags_prop.DidChange()) {
+ tags_val = strtoull(tags_prop.Get(), nullptr, 0);
}
g_lock.unlock();
- return g_tags & enable_tags;
+ return tags_val & enable_tags;
}
int get_trace_marker_fd() {
+ static int opened_trace_marker_fd = -1;
g_lock.lock();
- if (g_trace_marker_fd == -1) {
- g_trace_marker_fd = open("/sys/kernel/tracing/trace_marker", O_CLOEXEC | O_WRONLY);
- if (g_trace_marker_fd == -1) {
- g_trace_marker_fd = open("/sys/kernel/debug/tracing/trace_marker", O_CLOEXEC | O_WRONLY);
+ if (opened_trace_marker_fd == -1) {
+ opened_trace_marker_fd = open("/sys/kernel/tracing/trace_marker", O_CLOEXEC | O_WRONLY);
+ if (opened_trace_marker_fd == -1) {
+ opened_trace_marker_fd = open("/sys/kernel/debug/tracing/trace_marker", O_CLOEXEC | O_WRONLY);
}
}
g_lock.unlock();
- return g_trace_marker_fd;
+ return opened_trace_marker_fd;
}
// event could be 'B' for begin or 'E' for end.