3c501b50b4
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
112 lines
3.7 KiB
C++
112 lines
3.7 KiB
C++
/*
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* Copyright (C) 2012-2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <stdlib.h>
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#include <private/android_filesystem_config.h>
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#include "FlushCommand.h"
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#include "LogBuffer.h"
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#include "LogBufferElement.h"
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#include "LogCommand.h"
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#include "LogReader.h"
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#include "LogTimes.h"
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#include "LogUtils.h"
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FlushCommand::FlushCommand(LogReader& reader, bool nonBlock, unsigned long tail,
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unsigned int logMask, pid_t pid, log_time start,
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uint64_t timeout)
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: mReader(reader),
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mNonBlock(nonBlock),
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mTail(tail),
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mLogMask(logMask),
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mPid(pid),
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mStart(start),
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mTimeout((start != log_time::EPOCH) ? timeout : 0) {
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}
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// runSocketCommand is called once for every open client on the
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// log reader socket. Here we manage and associated the reader
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// client tracking and log region locks LastLogTimes list of
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// LogTimeEntrys, and spawn a transitory per-client thread to
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// work at filing data to the socket.
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//
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// global LogTimeEntry::wrlock() is used to protect access,
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// reference counts are used to ensure that individual
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// LogTimeEntry lifetime is managed when not protected.
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void FlushCommand::runSocketCommand(SocketClient* client) {
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LogTimeEntry* entry = NULL;
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LastLogTimes& times = mReader.logbuf().mTimes;
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LogTimeEntry::wrlock();
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LastLogTimes::iterator it = times.begin();
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while (it != times.end()) {
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entry = (*it);
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if (entry->mClient == client) {
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if (entry->mTimeout.tv_sec || entry->mTimeout.tv_nsec) {
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if (mReader.logbuf().isMonotonic()) {
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LogTimeEntry::unlock();
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return;
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}
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// If the user changes the time in a gross manner that
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// invalidates the timeout, fall through and trigger.
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log_time now(CLOCK_REALTIME);
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if (((entry->mEnd + entry->mTimeout) > now) &&
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(now > entry->mEnd)) {
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LogTimeEntry::unlock();
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return;
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}
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}
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entry->triggerReader_Locked();
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if (entry->runningReader_Locked()) {
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LogTimeEntry::unlock();
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return;
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}
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entry->incRef_Locked();
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break;
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}
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it++;
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}
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if (it == times.end()) {
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// Create LogTimeEntry in notifyNewLog() ?
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if (mTail == (unsigned long)-1) {
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LogTimeEntry::unlock();
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return;
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}
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entry = new LogTimeEntry(mReader, client, mNonBlock, mTail, mLogMask,
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mPid, mStart, mTimeout);
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times.push_front(entry);
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}
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client->incRef();
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// release client and entry reference counts once done
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entry->startReader_Locked();
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LogTimeEntry::unlock();
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}
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bool FlushCommand::hasReadLogs(SocketClient* client) {
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return clientHasLogCredentials(client);
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}
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static bool clientHasSecurityCredentials(SocketClient* client) {
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return (client->getUid() == AID_SYSTEM) || (client->getGid() == AID_SYSTEM);
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}
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bool FlushCommand::hasSecurityLogs(SocketClient* client) {
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return clientHasSecurityCredentials(client);
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}
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