/
db_partition.cc
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/
db_partition.cc
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/*
* Copyright (c) 2013 Juniper Networks, Inc. All rights reserved.
*/
#include "db/db_partition.h"
#include <list>
#include <tbb/atomic.h>
#include <tbb/concurrent_queue.h>
#include <tbb/mutex.h>
#include "base/task.h"
#include "db/db_client.h"
#include "db/db_entry.h"
using tbb::concurrent_queue;
using tbb::atomic;
int DBPartition::db_partition_task_id_ = -1;
struct RequestQueueEntry {
// Constructor takes ownership of DBRequest key, data.
RequestQueueEntry(DBTablePartBase *tpart, DBClient *client, DBRequest *req)
: tpart(tpart), client(client) {
request.Swap(req);
}
DBTablePartBase *tpart;
DBClient *client;
DBRequest request;
};
struct RemoveQueueEntry {
RemoveQueueEntry(DBTablePartBase *tpart, DBEntryBase *db_entry)
: tpart(tpart), db_entry(db_entry) {
}
DBTablePartBase *tpart;
DBEntryBase *db_entry;
};
class DBPartition::WorkQueue {
public:
static const int kThreshold = 1024;
typedef concurrent_queue<RequestQueueEntry *> RequestQueue;
typedef concurrent_queue<RemoveQueueEntry *> RemoveQueue;
typedef std::list<DBTablePartBase *> TablePartList;
explicit WorkQueue(int partition_id)
: db_partition_id_(partition_id), disable_(false), running_(false) {
request_count_ = 0;
max_request_queue_len_ = 0;
total_request_count_ = 0;
}
~WorkQueue() {
for (RequestQueue::iterator iter = request_queue_.unsafe_begin();
iter != request_queue_.unsafe_end();) {
RequestQueueEntry *req_entry = *iter;
++iter;
delete req_entry;
}
request_queue_.clear();
}
bool EnqueueRequest(RequestQueueEntry *req_entry) {
request_queue_.push(req_entry);
MaybeStartRunner();
uint32_t max = request_count_.fetch_and_increment();
if (max > max_request_queue_len_)
max_request_queue_len_ = max;
total_request_count_++;
return max < (kThreshold - 1);
}
bool DequeueRequest(RequestQueueEntry **req_entry) {
bool success = request_queue_.try_pop(*req_entry);
if (success) {
request_count_.fetch_and_decrement();
}
return success;
}
void EnqueueRemove(RemoveQueueEntry *rm_entry) {
remove_queue_.push(rm_entry);
MaybeStartRunner();
}
bool DequeueRemove(RemoveQueueEntry **rm_entry) {
bool success = remove_queue_.try_pop(*rm_entry);
return success;
}
void MaybeStartRunner();
bool RunnerDone();
void SetActive(DBTablePartBase *tpart) {
change_list_.push_back(tpart);
MaybeStartRunner();
}
DBTablePartBase *GetActiveTable() {
DBTablePartBase *tpart = NULL;
if (!change_list_.empty()) {
tpart = change_list_.front();
change_list_.pop_front();
}
return tpart;
}
int db_partition_id() {
return db_partition_id_;
}
bool IsDBQueueEmpty() const {
return (request_queue_.empty() && change_list_.empty());
}
bool disable() { return disable_; }
void set_disable(bool disable) { disable_ = disable; }
long request_queue_len() const {
return request_count_;
}
uint64_t total_request_count() const {
return total_request_count_;
}
uint64_t max_request_queue_len() const {
return max_request_queue_len_;
}
private:
RequestQueue request_queue_;
TablePartList change_list_;
atomic<long> request_count_;
uint64_t total_request_count_;
uint64_t max_request_queue_len_;
RemoveQueue remove_queue_;
tbb::mutex mutex_;
int db_partition_id_;
bool disable_;
bool running_;
DISALLOW_COPY_AND_ASSIGN(WorkQueue);
};
bool DBPartition::IsDBQueueEmpty() const {
return work_queue_->IsDBQueueEmpty();
}
void DBPartition::SetQueueDisable(bool disable) {
if (disable) {
work_queue_->set_disable(true);
} else {
work_queue_->set_disable(false);
work_queue_->MaybeStartRunner();
}
}
class DBPartition::QueueRunner : public Task {
public:
static const int kMaxIterations = 32;
QueueRunner(WorkQueue *queue)
: Task(db_partition_task_id_, queue->db_partition_id()),
queue_(queue) {
}
virtual bool Run() {
int count = 0;
// Skip if the queue is disabled.
if (queue_->disable())
return queue_->RunnerDone();
RemoveQueueEntry *rm_entry = NULL;
while (queue_->DequeueRemove(&rm_entry)) {
if (rm_entry->db_entry->IsDeleted() &&
!rm_entry->db_entry->is_onlist() &&
rm_entry->db_entry->is_state_empty(rm_entry->tpart)) {
rm_entry->tpart->Remove(rm_entry->db_entry);
} else {
rm_entry->db_entry->ClearOnRemoveQ();
}
delete rm_entry;
if (++count == kMaxIterations) {
return false;
}
}
RequestQueueEntry *req_entry = NULL;
while (queue_->DequeueRequest(&req_entry)) {
req_entry->tpart->Process(req_entry->client, &req_entry->request);
delete req_entry;
if (++count == kMaxIterations) {
return false;
}
}
while (true) {
DBTablePartBase *tpart = queue_->GetActiveTable();
if (tpart == NULL) {
break;
}
bool done = tpart->RunNotify();
if (!done) {
return false;
}
}
// Running is done only if queue_ is empty. It's possible that more
// entries are added into in the input or remove queues during the
// time we were processing those queues.
return queue_->RunnerDone();
}
std::string Description() const {
return "DBPartition QueueRunner";
}
private:
WorkQueue *queue_;
};
void DBPartition::WorkQueue::MaybeStartRunner() {
tbb::mutex::scoped_lock lock(mutex_);
if (running_) {
return;
}
running_ = true;
QueueRunner *runner = new QueueRunner(this);
TaskScheduler *scheduler = TaskScheduler::GetInstance();
scheduler->Enqueue(runner);
}
bool DBPartition::WorkQueue::RunnerDone() {
tbb::mutex::scoped_lock lock(mutex_);
if (disable_ || (request_queue_.empty() && remove_queue_.empty())) {
running_ = false;
return true;
}
running_ = true;
return false;
}
DBPartition::DBPartition(int partition_id)
: work_queue_(new WorkQueue(partition_id)) {
if (db_partition_task_id_ == -1) {
TaskScheduler *scheduler = TaskScheduler::GetInstance();
db_partition_task_id_ = scheduler->GetTaskId("db::DBTable");
}
}
// The DBPartition destructor needs to be defined after WorkQueue has
// been declared.
DBPartition::~DBPartition() {
}
bool DBPartition::EnqueueRequest(DBTablePartBase *tpart, DBClient *client,
DBRequest *req) {
RequestQueueEntry *entry = new RequestQueueEntry(tpart, client, req);
return work_queue_->EnqueueRequest(entry);
}
void DBPartition::EnqueueRemove(DBTablePartBase *tpart, DBEntryBase *db_entry) {
RemoveQueueEntry *entry = new RemoveQueueEntry(tpart, db_entry);
db_entry->SetOnRemoveQ();
work_queue_->EnqueueRemove(entry);
}
// concurrency: called from DBPartition task.
void DBPartition::OnTableChange(DBTablePartBase *tablepart) {
work_queue_->SetActive(tablepart);
}
long DBPartition::request_queue_len() const {
return work_queue_->request_queue_len();
}
uint64_t DBPartition::total_request_count() const {
return work_queue_->total_request_count();
}
uint64_t DBPartition::max_request_queue_len() const {
return work_queue_->max_request_queue_len();
}