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/LogReader.cpp b/logd/LogReader.cpp
index feb105f..6d69316 100644
--- a/logd/LogReader.cpp
+++ b/logd/LogReader.cpp
@@ -111,7 +111,7 @@
if (!fastcmp<strncmp>(buffer, "dumpAndClose", 12)) {
// Allow writer to get some cycles, and wait for pending notifications
sched_yield();
- LogTimeEntry::lock();
+ LogTimeEntry::wrlock();
LogTimeEntry::unlock();
sched_yield();
nonBlock = true;
@@ -212,7 +212,7 @@
void LogReader::doSocketDelete(SocketClient* cli) {
LastLogTimes& times = mLogbuf.mTimes;
- LogTimeEntry::lock();
+ LogTimeEntry::wrlock();
LastLogTimes::iterator it = times.begin();
while (it != times.end()) {
LogTimeEntry* entry = (*it);