logd: use a std::list<> of values not pointers
This saves 4 or 8 bytes off of each log message for 32 bit or 64 bit
devices respectively. In practice, this actually saves more, due to
avoiding heap fragmentation.
Averaging over 5 runs of the LogBufferTest.random_messages unit test
(32 bit), this change results in 8k less memory used when 1000 logs
are logged and results in 260k less memory used when 10000 logs are
logged.
Test: check memory usage during LogBufferTest.random_messages
Test: logging unit tests
Change-Id: Ia7953e3c4cb19631ef43bab1deb91bb336bc2520
diff --git a/logd/ChattyLogBuffer.h b/logd/ChattyLogBuffer.h
index d307a5e..08c4bff 100644
--- a/logd/ChattyLogBuffer.h
+++ b/logd/ChattyLogBuffer.h
@@ -37,7 +37,7 @@
#include "LogWriter.h"
#include "rwlock.h"
-typedef std::list<LogBufferElement*> LogBufferElementCollection;
+typedef std::list<LogBufferElement> LogBufferElementCollection;
class ChattyLogBuffer : public LogBuffer {
LogBufferElementCollection mLogElements GUARDED_BY(lock_);
@@ -75,7 +75,7 @@
LogBufferElementCollection::iterator erase(LogBufferElementCollection::iterator it,
bool coalesce = false) REQUIRES(lock_);
bool ShouldLog(log_id_t log_id, const char* msg, uint16_t len);
- void Log(std::unique_ptr<LogBufferElement> elem) REQUIRES(lock_);
+ void Log(LogBufferElement&& elem) REQUIRES(lock_);
// Returns an iterator to the oldest element for a given log type, or mLogElements.end() if
// there are no logs for the given log type. Requires mLogElementsLock to be held.
@@ -93,8 +93,8 @@
RwLock lock_;
// This always contains a copy of the last message logged, for deduplication.
- std::unique_ptr<LogBufferElement> last_logged_elements_[LOG_ID_MAX] GUARDED_BY(lock_);
+ std::optional<LogBufferElement> last_logged_elements_[LOG_ID_MAX] GUARDED_BY(lock_);
// This contains an element if duplicate messages are seen.
// Its `dropped` count is `duplicates seen - 1`.
- std::unique_ptr<LogBufferElement> duplicate_elements_[LOG_ID_MAX] GUARDED_BY(lock_);
+ std::optional<LogBufferElement> duplicate_elements_[LOG_ID_MAX] GUARDED_BY(lock_);
};