logd: reader/writer element locks
Switch to a reader writer lock for the Element List lock. Also setup
for a reader writer lock for the Times list, but continue to use a
mutex where rdlock() and wrlock() are the same implementation for now.
This should improve general reader performance and prevent blocking of
other reader operations or exit by a single hung logd.reader.per
thread. For example, a full length logcat of an empty buffer (eg:
crash log buffer) will hold a lock while the iterator scans the entire
list.
Test: gTest liblog-unit-tests, logd-unit-tests, logcat-unit-tests
Bug: 37378309
Bug: 37483775
Change-Id: If5723ff4a978e17d828a75321e8f0ba91d4a09e0
diff --git a/logd/LogTimes.cpp b/logd/LogTimes.cpp
index ccc550a..25c2ad2 100644
--- a/logd/LogTimes.cpp
+++ b/logd/LogTimes.cpp
@@ -78,7 +78,7 @@
void LogTimeEntry::threadStop(void* obj) {
LogTimeEntry* me = reinterpret_cast<LogTimeEntry*>(obj);
- lock();
+ wrlock();
if (me->mNonBlock) {
me->error_Locked();
@@ -134,7 +134,7 @@
me->leadingDropped = true;
- lock();
+ wrlock();
log_time start = me->mStart;
@@ -160,7 +160,7 @@
start = logbuf.flushTo(client, start, me->mLastTid, privileged,
security, FilterSecondPass, me);
- lock();
+ wrlock();
if (start == LogBufferElement::FLUSH_ERROR) {
me->error_Locked();
@@ -191,7 +191,7 @@
int LogTimeEntry::FilterFirstPass(const LogBufferElement* element, void* obj) {
LogTimeEntry* me = reinterpret_cast<LogTimeEntry*>(obj);
- LogTimeEntry::lock();
+ LogTimeEntry::wrlock();
if (me->leadingDropped) {
if (element->getDropped()) {
@@ -219,7 +219,7 @@
int LogTimeEntry::FilterSecondPass(const LogBufferElement* element, void* obj) {
LogTimeEntry* me = reinterpret_cast<LogTimeEntry*>(obj);
- LogTimeEntry::lock();
+ LogTimeEntry::wrlock();
me->mStart = element->getRealTime();