cmds/statsd/src/external/StatsPullerManager.cpp - android_frameworks_base - Gitiles

 /*
  * Copyright (C) 2017 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.
  */

 #define DEBUG false
 #include "Log.h"

 #include "StatsPullerManager.h"

 #include <cutils/log.h>
 #include <math.h>
 #include <stdint.h>

 #include <algorithm>
 #include <iostream>

 #include "../StatsService.h"
 #include "../logd/LogEvent.h"
 #include "../stats_log_util.h"
 #include "../statscompanion_util.h"
 #include "StatsCallbackPuller.h"
 #include "TrainInfoPuller.h"
 #include "statslog_statsd.h"

 using std::shared_ptr;
 using std::vector;

 namespace android {
 namespace os {
 namespace statsd {

 // Stores the puller as a wp to avoid holding a reference in case it is unregistered and
 // pullAtomCallbackDied is never called.
 struct PullAtomCallbackDeathCookie {
     PullAtomCallbackDeathCookie(const wp<StatsPullerManager>& pullerManager,
                                 const PullerKey& pullerKey, const wp<StatsPuller>& puller) :
             mPullerManager(pullerManager), mPullerKey(pullerKey), mPuller(puller) {
     }

     wp<StatsPullerManager> mPullerManager;
     PullerKey mPullerKey;
     wp<StatsPuller> mPuller;
 };

 void StatsPullerManager::pullAtomCallbackDied(void* cookie) {
     PullAtomCallbackDeathCookie* cookie_ = static_cast<PullAtomCallbackDeathCookie*>(cookie);
     sp<StatsPullerManager> thiz = cookie_->mPullerManager.promote();
     if (!thiz) {
         return;
     }

     const PullerKey& pullerKey = cookie_->mPullerKey;
     wp<StatsPuller> puller = cookie_->mPuller;

     // Erase the mapping from the puller key to the puller if the mapping still exists.
     // Note that we are removing the StatsPuller object, which internally holds the binder
     // IPullAtomCallback. However, each new registration creates a new StatsPuller, so this works.
     lock_guard<mutex> lock(thiz->mLock);
     const auto& it = thiz->kAllPullAtomInfo.find(pullerKey);
     if (it != thiz->kAllPullAtomInfo.end() && puller != nullptr && puller == it->second) {
         StatsdStats::getInstance().notePullerCallbackRegistrationChanged(pullerKey.atomTag,
                                                                          /*registered=*/false);
         thiz->kAllPullAtomInfo.erase(pullerKey);
     }
     // The death recipient corresponding to this specific IPullAtomCallback can never
     // be triggered again, so free up resources.
     delete cookie_;
 }

 // Values smaller than this may require to update the alarm.
 const int64_t NO_ALARM_UPDATE = INT64_MAX;

 StatsPullerManager::StatsPullerManager()
     : kAllPullAtomInfo({
               // TrainInfo.
               {{.atomTag = util::TRAIN_INFO, .uid = AID_STATSD}, new TrainInfoPuller()},
       }),
       mNextPullTimeNs(NO_ALARM_UPDATE),
       mPullAtomCallbackDeathRecipient(AIBinder_DeathRecipient_new(pullAtomCallbackDied)) {
 }

 bool StatsPullerManager::Pull(int tagId, const ConfigKey& configKey, const int64_t eventTimeNs,
                               vector<shared_ptr<LogEvent>>* data) {
     std::lock_guard<std::mutex> _l(mLock);
     return PullLocked(tagId, configKey, eventTimeNs, data);
 }

 bool StatsPullerManager::Pull(int tagId, const vector<int32_t>& uids, const int64_t eventTimeNs,
                               vector<std::shared_ptr<LogEvent>>* data) {
     std::lock_guard<std::mutex> _l(mLock);
     return PullLocked(tagId, uids, eventTimeNs, data);
 }

 bool StatsPullerManager::PullLocked(int tagId, const ConfigKey& configKey,
                                     const int64_t eventTimeNs, vector<shared_ptr<LogEvent>>* data) {
     vector<int32_t> uids;
     const auto& uidProviderIt = mPullUidProviders.find(configKey);
     if (uidProviderIt == mPullUidProviders.end()) {
         ALOGE("Error pulling tag %d. No pull uid provider for config key %s", tagId,
               configKey.ToString().c_str());
         StatsdStats::getInstance().notePullUidProviderNotFound(tagId);
         return false;
     }
     sp<PullUidProvider> pullUidProvider = uidProviderIt->second.promote();
     if (pullUidProvider == nullptr) {
         ALOGE("Error pulling tag %d, pull uid provider for config %s is gone.", tagId,
               configKey.ToString().c_str());
         StatsdStats::getInstance().notePullUidProviderNotFound(tagId);
         return false;
     }
     uids = pullUidProvider->getPullAtomUids(tagId);
     return PullLocked(tagId, uids, eventTimeNs, data);
 }

 bool StatsPullerManager::PullLocked(int tagId, const vector<int32_t>& uids,
                                     const int64_t eventTimeNs, vector<shared_ptr<LogEvent>>* data) {
     VLOG("Initiating pulling %d", tagId);
     for (int32_t uid : uids) {
         PullerKey key = {.atomTag = tagId, .uid = uid};
         auto pullerIt = kAllPullAtomInfo.find(key);
         if (pullerIt != kAllPullAtomInfo.end()) {
             bool ret = pullerIt->second->Pull(eventTimeNs, data);
             VLOG("pulled %zu items", data->size());
             if (!ret) {
                 StatsdStats::getInstance().notePullFailed(tagId);
             }
             return ret;
         }
     }
     StatsdStats::getInstance().notePullerNotFound(tagId);
     ALOGW("StatsPullerManager: Unknown tagId %d", tagId);
     return false;  // Return early since we don't know what to pull.
 }

 bool StatsPullerManager::PullerForMatcherExists(int tagId) const {
     // Pulled atoms might be registered after we parse the config, so just make sure the id is in
     // an appropriate range.
     return isVendorPulledAtom(tagId) || isPulledAtom(tagId);
 }

 void StatsPullerManager::updateAlarmLocked() {
     if (mNextPullTimeNs == NO_ALARM_UPDATE) {
         VLOG("No need to set alarms. Skipping");
         return;
     }

     // TODO(b/151045771): do not hold a lock while making a binder call
     if (mStatsCompanionService != nullptr) {
         mStatsCompanionService->setPullingAlarm(mNextPullTimeNs / 1000000);
     } else {
         VLOG("StatsCompanionService not available. Alarm not set.");
     }
     return;
 }

 void StatsPullerManager::SetStatsCompanionService(
         shared_ptr<IStatsCompanionService> statsCompanionService) {
     std::lock_guard<std::mutex> _l(mLock);
     shared_ptr<IStatsCompanionService> tmpForLock = mStatsCompanionService;
     mStatsCompanionService = statsCompanionService;
     for (const auto& pulledAtom : kAllPullAtomInfo) {
         pulledAtom.second->SetStatsCompanionService(statsCompanionService);
     }
     if (mStatsCompanionService != nullptr) {
         updateAlarmLocked();
     }
 }

 void StatsPullerManager::RegisterReceiver(int tagId, const ConfigKey& configKey,
                                           wp<PullDataReceiver> receiver, int64_t nextPullTimeNs,
                                           int64_t intervalNs) {
     std::lock_guard<std::mutex> _l(mLock);
     auto& receivers = mReceivers[{.atomTag = tagId, .configKey = configKey}];
     for (auto it = receivers.begin(); it != receivers.end(); it++) {
         if (it->receiver == receiver) {
             VLOG("Receiver already registered of %d", (int)receivers.size());
             return;
         }
     }
     ReceiverInfo receiverInfo;
     receiverInfo.receiver = receiver;

     // Round it to the nearest minutes. This is the limit of alarm manager.
     // In practice, we should always have larger buckets.
     int64_t roundedIntervalNs = intervalNs / NS_PER_SEC / 60 * NS_PER_SEC * 60;
     // Scheduled pulling should be at least 1 min apart.
     // This can be lower in cts tests, in which case we round it to 1 min.
     if (roundedIntervalNs < 60 * (int64_t)NS_PER_SEC) {
         roundedIntervalNs = 60 * (int64_t)NS_PER_SEC;
     }

     receiverInfo.intervalNs = roundedIntervalNs;
     receiverInfo.nextPullTimeNs = nextPullTimeNs;
     receivers.push_back(receiverInfo);

     // There is only one alarm for all pulled events. So only set it to the smallest denom.
     if (nextPullTimeNs < mNextPullTimeNs) {
         VLOG("Updating next pull time %lld", (long long)mNextPullTimeNs);
         mNextPullTimeNs = nextPullTimeNs;
         updateAlarmLocked();
     }
     VLOG("Puller for tagId %d registered of %d", tagId, (int)receivers.size());
 }

 void StatsPullerManager::UnRegisterReceiver(int tagId, const ConfigKey& configKey,
                                             wp<PullDataReceiver> receiver) {
     std::lock_guard<std::mutex> _l(mLock);
     auto receiversIt = mReceivers.find({.atomTag = tagId, .configKey = configKey});
     if (receiversIt == mReceivers.end()) {
         VLOG("Unknown pull code or no receivers: %d", tagId);
         return;
     }
     std::list<ReceiverInfo>& receivers = receiversIt->second;
     for (auto it = receivers.begin(); it != receivers.end(); it++) {
         if (receiver == it->receiver) {
             receivers.erase(it);
             VLOG("Puller for tagId %d unregistered of %d", tagId, (int)receivers.size());
             return;
         }
     }
 }

 void StatsPullerManager::RegisterPullUidProvider(const ConfigKey& configKey,
                                                  wp<PullUidProvider> provider) {
     std::lock_guard<std::mutex> _l(mLock);
     mPullUidProviders[configKey] = provider;
 }

 void StatsPullerManager::UnregisterPullUidProvider(const ConfigKey& configKey,
                                                    wp<PullUidProvider> provider) {
     std::lock_guard<std::mutex> _l(mLock);
     const auto& it = mPullUidProviders.find(configKey);
     if (it != mPullUidProviders.end() && it->second == provider) {
         mPullUidProviders.erase(it);
     }
 }

 void StatsPullerManager::OnAlarmFired(int64_t elapsedTimeNs) {
     std::lock_guard<std::mutex> _l(mLock);
     int64_t wallClockNs = getWallClockNs();

     int64_t minNextPullTimeNs = NO_ALARM_UPDATE;

     vector<pair<const ReceiverKey*, vector<ReceiverInfo*>>> needToPull;
     for (auto& pair : mReceivers) {
         vector<ReceiverInfo*> receivers;
         if (pair.second.size() != 0) {
             for (ReceiverInfo& receiverInfo : pair.second) {
                 if (receiverInfo.nextPullTimeNs <= elapsedTimeNs) {
                     receivers.push_back(&receiverInfo);
                 } else {
                     if (receiverInfo.nextPullTimeNs < minNextPullTimeNs) {
                         minNextPullTimeNs = receiverInfo.nextPullTimeNs;
                     }
                 }
             }
             if (receivers.size() > 0) {
                 needToPull.push_back(make_pair(&pair.first, receivers));
             }
         }
     }
     for (const auto& pullInfo : needToPull) {
         vector<shared_ptr<LogEvent>> data;
         bool pullSuccess = PullLocked(pullInfo.first->atomTag, pullInfo.first->configKey,
                                       elapsedTimeNs, &data);
         if (!pullSuccess) {
             VLOG("pull failed at %lld, will try again later", (long long)elapsedTimeNs);
         }

         // Convention is to mark pull atom timestamp at request time.
         // If we pull at t0, puller starts at t1, finishes at t2, and send back
         // at t3, we mark t0 as its timestamp, which should correspond to its
         // triggering event, such as condition change at t0.
         // Here the triggering event is alarm fired from AlarmManager.
         // In ValueMetricProducer and GaugeMetricProducer we do same thing
         // when pull on condition change, etc.
         for (auto& event : data) {
             event->setElapsedTimestampNs(elapsedTimeNs);
             event->setLogdWallClockTimestampNs(wallClockNs);
         }

         for (const auto& receiverInfo : pullInfo.second) {
             sp<PullDataReceiver> receiverPtr = receiverInfo->receiver.promote();
             if (receiverPtr != nullptr) {
                 receiverPtr->onDataPulled(data, pullSuccess, elapsedTimeNs);
                 // We may have just come out of a coma, compute next pull time.
                 int numBucketsAhead =
                         (elapsedTimeNs - receiverInfo->nextPullTimeNs) / receiverInfo->intervalNs;
                 receiverInfo->nextPullTimeNs += (numBucketsAhead + 1) * receiverInfo->intervalNs;
                 if (receiverInfo->nextPullTimeNs < minNextPullTimeNs) {
                     minNextPullTimeNs = receiverInfo->nextPullTimeNs;
                 }
             } else {
                 VLOG("receiver already gone.");
             }
         }
     }

     VLOG("mNextPullTimeNs: %lld updated to %lld", (long long)mNextPullTimeNs,
          (long long)minNextPullTimeNs);
     mNextPullTimeNs = minNextPullTimeNs;
     updateAlarmLocked();
 }

 int StatsPullerManager::ForceClearPullerCache() {
     std::lock_guard<std::mutex> _l(mLock);
     int totalCleared = 0;
     for (const auto& pulledAtom : kAllPullAtomInfo) {
         totalCleared += pulledAtom.second->ForceClearCache();
     }
     return totalCleared;
 }

 int StatsPullerManager::ClearPullerCacheIfNecessary(int64_t timestampNs) {
     std::lock_guard<std::mutex> _l(mLock);
     int totalCleared = 0;
     for (const auto& pulledAtom : kAllPullAtomInfo) {
         totalCleared += pulledAtom.second->ClearCacheIfNecessary(timestampNs);
     }
     return totalCleared;
 }

 void StatsPullerManager::RegisterPullAtomCallback(const int uid, const int32_t atomTag,
                                                   const int64_t coolDownNs, const int64_t timeoutNs,
                                                   const vector<int32_t>& additiveFields,
                                                   const shared_ptr<IPullAtomCallback>& callback) {
     std::lock_guard<std::mutex> _l(mLock);
     VLOG("RegisterPullerCallback: adding puller for tag %d", atomTag);

     if (callback == nullptr) {
         ALOGW("SetPullAtomCallback called with null callback for atom %d.", atomTag);
         return;
     }

     StatsdStats::getInstance().notePullerCallbackRegistrationChanged(atomTag, /*registered=*/true);
     int64_t actualCoolDownNs = coolDownNs < kMinCoolDownNs ? kMinCoolDownNs : coolDownNs;
     int64_t actualTimeoutNs = timeoutNs > kMaxTimeoutNs ? kMaxTimeoutNs : timeoutNs;

     sp<StatsCallbackPuller> puller = new StatsCallbackPuller(atomTag, callback, actualCoolDownNs,
                                                              actualTimeoutNs, additiveFields);
     PullerKey key = {.atomTag = atomTag, .uid = uid};
     AIBinder_linkToDeath(callback->asBinder().get(), mPullAtomCallbackDeathRecipient.get(),
                          new PullAtomCallbackDeathCookie(this, key, puller));
     kAllPullAtomInfo[key] = puller;
 }

 void StatsPullerManager::UnregisterPullAtomCallback(const int uid, const int32_t atomTag) {
     std::lock_guard<std::mutex> _l(mLock);
     PullerKey key = {.atomTag = atomTag, .uid = uid};
     if (kAllPullAtomInfo.find(key) != kAllPullAtomInfo.end()) {
         StatsdStats::getInstance().notePullerCallbackRegistrationChanged(atomTag,
                                                                          /*registered=*/false);
         kAllPullAtomInfo.erase(key);
     }
 }

 }  // namespace statsd
 }  // namespace os
 }  // namespace android
	/*
	* Copyright (C) 2017 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.
	*/

	#define DEBUG false
	#include "Log.h"

	#include "StatsPullerManager.h"

	#include <cutils/log.h>
	#include <math.h>
	#include <stdint.h>

	#include <algorithm>
	#include <iostream>

	#include "../StatsService.h"
	#include "../logd/LogEvent.h"
	#include "../stats_log_util.h"
	#include "../statscompanion_util.h"
	#include "StatsCallbackPuller.h"
	#include "TrainInfoPuller.h"
	#include "statslog_statsd.h"

	using std::shared_ptr;
	using std::vector;

	namespace android {
	namespace os {
	namespace statsd {

	// Stores the puller as a wp to avoid holding a reference in case it is unregistered and
	// pullAtomCallbackDied is never called.
	struct PullAtomCallbackDeathCookie {
	PullAtomCallbackDeathCookie(const wp<StatsPullerManager>& pullerManager,
	const PullerKey& pullerKey, const wp<StatsPuller>& puller) :
	mPullerManager(pullerManager), mPullerKey(pullerKey), mPuller(puller) {
	}

	wp<StatsPullerManager> mPullerManager;
	PullerKey mPullerKey;
	wp<StatsPuller> mPuller;
	};

	void StatsPullerManager::pullAtomCallbackDied(void* cookie) {
	PullAtomCallbackDeathCookie* cookie_ = static_cast<PullAtomCallbackDeathCookie*>(cookie);
	sp<StatsPullerManager> thiz = cookie_->mPullerManager.promote();
	if (!thiz) {
	return;
	}

	const PullerKey& pullerKey = cookie_->mPullerKey;
	wp<StatsPuller> puller = cookie_->mPuller;

	// Erase the mapping from the puller key to the puller if the mapping still exists.
	// Note that we are removing the StatsPuller object, which internally holds the binder
	// IPullAtomCallback. However, each new registration creates a new StatsPuller, so this works.
	lock_guard<mutex> lock(thiz->mLock);
	const auto& it = thiz->kAllPullAtomInfo.find(pullerKey);
	if (it != thiz->kAllPullAtomInfo.end() && puller != nullptr && puller == it->second) {
	StatsdStats::getInstance().notePullerCallbackRegistrationChanged(pullerKey.atomTag,
	/registered=/false);
	thiz->kAllPullAtomInfo.erase(pullerKey);
	}
	// The death recipient corresponding to this specific IPullAtomCallback can never
	// be triggered again, so free up resources.
	delete cookie_;
	}

	// Values smaller than this may require to update the alarm.
	const int64_t NO_ALARM_UPDATE = INT64_MAX;

	StatsPullerManager::StatsPullerManager()
	: kAllPullAtomInfo({
	// TrainInfo.
	{{.atomTag = util::TRAIN_INFO, .uid = AID_STATSD}, new TrainInfoPuller()},
	}),
	mNextPullTimeNs(NO_ALARM_UPDATE),
	mPullAtomCallbackDeathRecipient(AIBinder_DeathRecipient_new(pullAtomCallbackDied)) {
	}

	bool StatsPullerManager::Pull(int tagId, const ConfigKey& configKey, const int64_t eventTimeNs,
	vector<shared_ptr<LogEvent>>* data) {
	std::lock_guard<std::mutex> _l(mLock);
	return PullLocked(tagId, configKey, eventTimeNs, data);
	}

	bool StatsPullerManager::Pull(int tagId, const vector<int32_t>& uids, const int64_t eventTimeNs,
	vector<std::shared_ptr<LogEvent>>* data) {
	std::lock_guard<std::mutex> _l(mLock);
	return PullLocked(tagId, uids, eventTimeNs, data);
	}

	bool StatsPullerManager::PullLocked(int tagId, const ConfigKey& configKey,
	const int64_t eventTimeNs, vector<shared_ptr<LogEvent>>* data) {
	vector<int32_t> uids;
	const auto& uidProviderIt = mPullUidProviders.find(configKey);
	if (uidProviderIt == mPullUidProviders.end()) {
	ALOGE("Error pulling tag %d. No pull uid provider for config key %s", tagId,
	configKey.ToString().c_str());
	StatsdStats::getInstance().notePullUidProviderNotFound(tagId);
	return false;
	}
	sp<PullUidProvider> pullUidProvider = uidProviderIt->second.promote();
	if (pullUidProvider == nullptr) {
	ALOGE("Error pulling tag %d, pull uid provider for config %s is gone.", tagId,
	configKey.ToString().c_str());
	StatsdStats::getInstance().notePullUidProviderNotFound(tagId);
	return false;
	}
	uids = pullUidProvider->getPullAtomUids(tagId);
	return PullLocked(tagId, uids, eventTimeNs, data);
	}

	bool StatsPullerManager::PullLocked(int tagId, const vector<int32_t>& uids,
	const int64_t eventTimeNs, vector<shared_ptr<LogEvent>>* data) {
	VLOG("Initiating pulling %d", tagId);
	for (int32_t uid : uids) {
	PullerKey key = {.atomTag = tagId, .uid = uid};
	auto pullerIt = kAllPullAtomInfo.find(key);
	if (pullerIt != kAllPullAtomInfo.end()) {
	bool ret = pullerIt->second->Pull(eventTimeNs, data);
	VLOG("pulled %zu items", data->size());
	if (!ret) {
	StatsdStats::getInstance().notePullFailed(tagId);
	}
	return ret;
	}
	}
	StatsdStats::getInstance().notePullerNotFound(tagId);
	ALOGW("StatsPullerManager: Unknown tagId %d", tagId);
	return false; // Return early since we don't know what to pull.
	}

	bool StatsPullerManager::PullerForMatcherExists(int tagId) const {
	// Pulled atoms might be registered after we parse the config, so just make sure the id is in
	// an appropriate range.
	return isVendorPulledAtom(tagId) \|\| isPulledAtom(tagId);
	}

	void StatsPullerManager::updateAlarmLocked() {
	if (mNextPullTimeNs == NO_ALARM_UPDATE) {
	VLOG("No need to set alarms. Skipping");
	return;
	}

	// TODO(b/151045771): do not hold a lock while making a binder call
	if (mStatsCompanionService != nullptr) {
	mStatsCompanionService->setPullingAlarm(mNextPullTimeNs / 1000000);
	} else {
	VLOG("StatsCompanionService not available. Alarm not set.");
	}
	return;
	}

	void StatsPullerManager::SetStatsCompanionService(
	shared_ptr<IStatsCompanionService> statsCompanionService) {
	std::lock_guard<std::mutex> _l(mLock);
	shared_ptr<IStatsCompanionService> tmpForLock = mStatsCompanionService;
	mStatsCompanionService = statsCompanionService;
	for (const auto& pulledAtom : kAllPullAtomInfo) {
	pulledAtom.second->SetStatsCompanionService(statsCompanionService);
	}
	if (mStatsCompanionService != nullptr) {
	updateAlarmLocked();
	}
	}

	void StatsPullerManager::RegisterReceiver(int tagId, const ConfigKey& configKey,
	wp<PullDataReceiver> receiver, int64_t nextPullTimeNs,
	int64_t intervalNs) {
	std::lock_guard<std::mutex> _l(mLock);
	auto& receivers = mReceivers[{.atomTag = tagId, .configKey = configKey}];
	for (auto it = receivers.begin(); it != receivers.end(); it++) {
	if (it->receiver == receiver) {
	VLOG("Receiver already registered of %d", (int)receivers.size());
	return;
	}
	}
	ReceiverInfo receiverInfo;
	receiverInfo.receiver = receiver;

	// Round it to the nearest minutes. This is the limit of alarm manager.
	// In practice, we should always have larger buckets.
	int64_t roundedIntervalNs = intervalNs / NS_PER_SEC / 60 * NS_PER_SEC * 60;
	// Scheduled pulling should be at least 1 min apart.
	// This can be lower in cts tests, in which case we round it to 1 min.
	if (roundedIntervalNs < 60 * (int64_t)NS_PER_SEC) {
	roundedIntervalNs = 60 * (int64_t)NS_PER_SEC;
	}

	receiverInfo.intervalNs = roundedIntervalNs;
	receiverInfo.nextPullTimeNs = nextPullTimeNs;
	receivers.push_back(receiverInfo);

	// There is only one alarm for all pulled events. So only set it to the smallest denom.
	if (nextPullTimeNs < mNextPullTimeNs) {
	VLOG("Updating next pull time %lld", (long long)mNextPullTimeNs);
	mNextPullTimeNs = nextPullTimeNs;
	updateAlarmLocked();
	}
	VLOG("Puller for tagId %d registered of %d", tagId, (int)receivers.size());
	}

	void StatsPullerManager::UnRegisterReceiver(int tagId, const ConfigKey& configKey,
	wp<PullDataReceiver> receiver) {
	std::lock_guard<std::mutex> _l(mLock);
	auto receiversIt = mReceivers.find({.atomTag = tagId, .configKey = configKey});
	if (receiversIt == mReceivers.end()) {
	VLOG("Unknown pull code or no receivers: %d", tagId);
	return;
	}
	std::list<ReceiverInfo>& receivers = receiversIt->second;
	for (auto it = receivers.begin(); it != receivers.end(); it++) {
	if (receiver == it->receiver) {
	receivers.erase(it);
	VLOG("Puller for tagId %d unregistered of %d", tagId, (int)receivers.size());
	return;
	}
	}
	}

	void StatsPullerManager::RegisterPullUidProvider(const ConfigKey& configKey,
	wp<PullUidProvider> provider) {
	std::lock_guard<std::mutex> _l(mLock);
	mPullUidProviders[configKey] = provider;
	}

	void StatsPullerManager::UnregisterPullUidProvider(const ConfigKey& configKey,
	wp<PullUidProvider> provider) {
	std::lock_guard<std::mutex> _l(mLock);
	const auto& it = mPullUidProviders.find(configKey);
	if (it != mPullUidProviders.end() && it->second == provider) {
	mPullUidProviders.erase(it);
	}
	}

	void StatsPullerManager::OnAlarmFired(int64_t elapsedTimeNs) {
	std::lock_guard<std::mutex> _l(mLock);
	int64_t wallClockNs = getWallClockNs();

	int64_t minNextPullTimeNs = NO_ALARM_UPDATE;

	vector<pair<const ReceiverKey, vector<ReceiverInfo>>> needToPull;
	for (auto& pair : mReceivers) {
	vector<ReceiverInfo*> receivers;
	if (pair.second.size() != 0) {
	for (ReceiverInfo& receiverInfo : pair.second) {
	if (receiverInfo.nextPullTimeNs <= elapsedTimeNs) {
	receivers.push_back(&receiverInfo);
	} else {
	if (receiverInfo.nextPullTimeNs < minNextPullTimeNs) {
	minNextPullTimeNs = receiverInfo.nextPullTimeNs;
	}
	}
	}
	if (receivers.size() > 0) {
	needToPull.push_back(make_pair(&pair.first, receivers));
	}
	}
	}
	for (const auto& pullInfo : needToPull) {
	vector<shared_ptr<LogEvent>> data;
	bool pullSuccess = PullLocked(pullInfo.first->atomTag, pullInfo.first->configKey,
	elapsedTimeNs, &data);
	if (!pullSuccess) {
	VLOG("pull failed at %lld, will try again later", (long long)elapsedTimeNs);
	}

	// Convention is to mark pull atom timestamp at request time.
	// If we pull at t0, puller starts at t1, finishes at t2, and send back
	// at t3, we mark t0 as its timestamp, which should correspond to its
	// triggering event, such as condition change at t0.
	// Here the triggering event is alarm fired from AlarmManager.
	// In ValueMetricProducer and GaugeMetricProducer we do same thing
	// when pull on condition change, etc.
	for (auto& event : data) {
	event->setElapsedTimestampNs(elapsedTimeNs);
	event->setLogdWallClockTimestampNs(wallClockNs);
	}

	for (const auto& receiverInfo : pullInfo.second) {
	sp<PullDataReceiver> receiverPtr = receiverInfo->receiver.promote();
	if (receiverPtr != nullptr) {
	receiverPtr->onDataPulled(data, pullSuccess, elapsedTimeNs);
	// We may have just come out of a coma, compute next pull time.
	int numBucketsAhead =
	(elapsedTimeNs - receiverInfo->nextPullTimeNs) / receiverInfo->intervalNs;
	receiverInfo->nextPullTimeNs += (numBucketsAhead + 1) * receiverInfo->intervalNs;
	if (receiverInfo->nextPullTimeNs < minNextPullTimeNs) {
	minNextPullTimeNs = receiverInfo->nextPullTimeNs;
	}
	} else {
	VLOG("receiver already gone.");
	}
	}
	}

	VLOG("mNextPullTimeNs: %lld updated to %lld", (long long)mNextPullTimeNs,
	(long long)minNextPullTimeNs);
	mNextPullTimeNs = minNextPullTimeNs;
	updateAlarmLocked();
	}

	int StatsPullerManager::ForceClearPullerCache() {
	std::lock_guard<std::mutex> _l(mLock);
	int totalCleared = 0;
	for (const auto& pulledAtom : kAllPullAtomInfo) {
	totalCleared += pulledAtom.second->ForceClearCache();
	}
	return totalCleared;
	}

	int StatsPullerManager::ClearPullerCacheIfNecessary(int64_t timestampNs) {
	std::lock_guard<std::mutex> _l(mLock);
	int totalCleared = 0;
	for (const auto& pulledAtom : kAllPullAtomInfo) {
	totalCleared += pulledAtom.second->ClearCacheIfNecessary(timestampNs);
	}
	return totalCleared;
	}

	void StatsPullerManager::RegisterPullAtomCallback(const int uid, const int32_t atomTag,
	const int64_t coolDownNs, const int64_t timeoutNs,
	const vector<int32_t>& additiveFields,
	const shared_ptr<IPullAtomCallback>& callback) {
	std::lock_guard<std::mutex> _l(mLock);
	VLOG("RegisterPullerCallback: adding puller for tag %d", atomTag);

	if (callback == nullptr) {
	ALOGW("SetPullAtomCallback called with null callback for atom %d.", atomTag);
	return;
	}

	StatsdStats::getInstance().notePullerCallbackRegistrationChanged(atomTag, /registered=/true);
	int64_t actualCoolDownNs = coolDownNs < kMinCoolDownNs ? kMinCoolDownNs : coolDownNs;
	int64_t actualTimeoutNs = timeoutNs > kMaxTimeoutNs ? kMaxTimeoutNs : timeoutNs;

	sp<StatsCallbackPuller> puller = new StatsCallbackPuller(atomTag, callback, actualCoolDownNs,
	actualTimeoutNs, additiveFields);
	PullerKey key = {.atomTag = atomTag, .uid = uid};
	AIBinder_linkToDeath(callback->asBinder().get(), mPullAtomCallbackDeathRecipient.get(),
	new PullAtomCallbackDeathCookie(this, key, puller));
	kAllPullAtomInfo[key] = puller;
	}

	void StatsPullerManager::UnregisterPullAtomCallback(const int uid, const int32_t atomTag) {
	std::lock_guard<std::mutex> _l(mLock);
	PullerKey key = {.atomTag = atomTag, .uid = uid};
	if (kAllPullAtomInfo.find(key) != kAllPullAtomInfo.end()) {
	StatsdStats::getInstance().notePullerCallbackRegistrationChanged(atomTag,
	/registered=/false);
	kAllPullAtomInfo.erase(key);
	}
	}

	} // namespace statsd
	} // namespace os
	} // namespace android