59caa7a045
When calculating the space used for pruning, if a log chunk is compressed, that size is used otherwise the uncompressed size is used. This is intended to reach a steady state where 1/4 of the log buffer is the uncompressed log chunk that is being written to and the other 3/4 of the log buffer is compressed logs. If we wait until there are no readers referencing the log chunk before compressing it, we end up with 2 uncompressed logs (the one that was just filled, that readers are still referencing, and the new one that was allocated to fit the most recent log), which take up 1/2 of the log buffer's allotted size and will thus cause prune to delete more compressed logs than it should. Instead, we should always compress the log chunks in FinishWriting() such that the compressed size will always be used for log chunks other than the one that is not actively written to. Decompressed logs due to readers are ephemeral by their nature and thus don't add to the log buffer size for pruning. Test: observe that log buffers can be filled in the presence of a reader. Change-Id: Ie21ccff032e41c4a0e51710cc435c5ab316563cb
76 lines
2.7 KiB
C++
76 lines
2.7 KiB
C++
/*
|
|
* Copyright (C) 2020 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.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <sys/types.h>
|
|
|
|
#include "LogWriter.h"
|
|
#include "SerializedData.h"
|
|
#include "SerializedLogEntry.h"
|
|
|
|
class SerializedLogChunk {
|
|
public:
|
|
explicit SerializedLogChunk(size_t size) : contents_(size) {}
|
|
SerializedLogChunk(SerializedLogChunk&& other) noexcept = default;
|
|
~SerializedLogChunk();
|
|
|
|
void Compress();
|
|
void IncReaderRefCount();
|
|
void DecReaderRefCount();
|
|
|
|
// Must have no readers referencing this. Return true if there are no logs left in this chunk.
|
|
bool ClearUidLogs(uid_t uid, log_id_t log_id, LogStatistics* stats);
|
|
|
|
bool CanLog(size_t len);
|
|
SerializedLogEntry* Log(uint64_t sequence, log_time realtime, uid_t uid, pid_t pid, pid_t tid,
|
|
const char* msg, uint16_t len);
|
|
|
|
// If this buffer has been compressed, we only consider its compressed size when accounting for
|
|
// memory consumption for pruning. This is since the uncompressed log is only by used by
|
|
// readers, and thus not a representation of how much these logs cost to keep in memory.
|
|
size_t PruneSize() const {
|
|
return sizeof(*this) + (compressed_log_.size() ?: contents_.size());
|
|
}
|
|
|
|
void FinishWriting() {
|
|
writer_active_ = false;
|
|
Compress();
|
|
if (reader_ref_count_ == 0) {
|
|
contents_.Resize(0);
|
|
}
|
|
}
|
|
|
|
const SerializedLogEntry* log_entry(int offset) const {
|
|
return reinterpret_cast<const SerializedLogEntry*>(data() + offset);
|
|
}
|
|
const uint8_t* data() const { return contents_.data(); }
|
|
int write_offset() const { return write_offset_; }
|
|
uint64_t highest_sequence_number() const { return highest_sequence_number_; }
|
|
|
|
// Exposed for testing
|
|
uint32_t reader_ref_count() const { return reader_ref_count_; }
|
|
|
|
private:
|
|
// The decompressed contents of this log buffer. Deallocated when the ref_count reaches 0 and
|
|
// writer_active_ is false.
|
|
SerializedData contents_;
|
|
int write_offset_ = 0;
|
|
uint32_t reader_ref_count_ = 0;
|
|
bool writer_active_ = true;
|
|
uint64_t highest_sequence_number_ = 1;
|
|
SerializedData compressed_log_;
|
|
};
|