platform_system_core/logd/LogBufferElement.h
Christopher Ferris 74e74f96a7 Decrease size of LogBufferElements to 32 bytes.
- Remove virtual from the destructor.
- Remove mTag and derive it when calling getTag().
- Add a boolean mDropped to tell when a message is dropped.
- When dropping a message, and it contains valid tag data, reallocate
  the message to only contain the tag data.
- Add the packed tag to the class.

This saves about ~150K of PSS on a typical log stream since it moves the
size of the LogBufferElement from 48 bytes to 32 bytes which puts it in
a smaller bin.

Bug: 63792187

Test: Builds, unit tests pass.
Change-Id: Ia5afce343ea3d344fcecd78c648338e94f5c9312
2017-08-11 12:48:11 -07:00

99 lines
3 KiB
C++

/*
* Copyright (C) 2012-2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _LOGD_LOG_BUFFER_ELEMENT_H__
#define _LOGD_LOG_BUFFER_ELEMENT_H__
#include <stdatomic.h>
#include <stdlib.h>
#include <sys/types.h>
#include <log/log.h>
#include <sysutils/SocketClient.h>
class LogBuffer;
#define EXPIRE_HOUR_THRESHOLD 24 // Only expire chatty UID logs to preserve
// non-chatty UIDs less than this age in hours
#define EXPIRE_THRESHOLD 10 // A smaller expire count is considered too
// chatty for the temporal expire messages
#define EXPIRE_RATELIMIT 10 // maximum rate in seconds to report expiration
class __attribute__((packed)) LogBufferElement {
friend LogBuffer;
// sized to match reality of incoming log packets
const uint32_t mUid;
const uint32_t mPid;
const uint32_t mTid;
log_time mRealTime;
char* mMsg;
union {
const uint16_t mMsgLen; // mDropped == false
uint16_t mDroppedCount; // mDropped == true
};
const uint8_t mLogId;
bool mDropped;
static atomic_int_fast64_t sequence;
// assumption: mDropped == true
size_t populateDroppedMessage(char*& buffer, LogBuffer* parent,
bool lastSame);
public:
LogBufferElement(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid,
pid_t tid, const char* msg, unsigned short len);
LogBufferElement(const LogBufferElement& elem);
~LogBufferElement();
bool isBinary(void) const {
return (mLogId == LOG_ID_EVENTS) || (mLogId == LOG_ID_SECURITY);
}
log_id_t getLogId() const {
return static_cast<log_id_t>(mLogId);
}
uid_t getUid(void) const {
return mUid;
}
pid_t getPid(void) const {
return mPid;
}
pid_t getTid(void) const {
return mTid;
}
uint32_t getTag() const;
unsigned short getDropped(void) const {
return mDropped ? mDroppedCount : 0;
}
unsigned short setDropped(unsigned short value);
unsigned short getMsgLen() const {
return mDropped ? 0 : mMsgLen;
}
const char* getMsg() const {
return mDropped ? nullptr : mMsg;
}
log_time getRealTime(void) const {
return mRealTime;
}
static const log_time FLUSH_ERROR;
log_time flushTo(SocketClient* writer, LogBuffer* parent, bool privileged,
bool lastSame);
};
#endif