mariadb/tpool/task_group.cc
2020-01-12 19:08:02 +01:00

100 lines
2.3 KiB
C++

/* Copyright(C) 2019 MariaDB Corporation.
This program is free software; you can redistribute itand /or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111 - 1301 USA*/
#include <tpool.h>
#include <queue>
#include <mutex>
#include <condition_variable>
#include <tpool_structs.h>
#include <thread>
#include <assert.h>
#ifndef _WIN32
#include <unistd.h> // usleep
#endif
namespace tpool
{
task_group::task_group(unsigned int max_concurrency) :
m_queue(8),
m_mtx(),
m_tasks_running(),
m_max_concurrent_tasks(max_concurrency)
{};
void task_group::set_max_tasks(unsigned int max_concurrency)
{
std::unique_lock<std::mutex> lk(m_mtx);
m_max_concurrent_tasks = max_concurrency;
}
void task_group::execute(task* t)
{
std::unique_lock<std::mutex> lk(m_mtx);
if (m_tasks_running == m_max_concurrent_tasks)
{
/* Queue for later execution by another thread.*/
m_queue.push(t);
return;
}
m_tasks_running++;
for (;;)
{
lk.unlock();
if (t)
{
t->m_func(t->m_arg);
dbug_execute_after_task_callback();
t->release();
}
lk.lock();
if (m_queue.empty())
break;
t = m_queue.front();
m_queue.pop();
}
m_tasks_running--;
}
void task_group::cancel_pending(task* t)
{
std::unique_lock<std::mutex> lk(m_mtx);
if (!t)
m_queue.clear();
for (auto it = m_queue.begin(); it != m_queue.end(); it++)
{
if (*it == t)
{
(*it)->release();
(*it) = nullptr;
}
}
}
task_group::~task_group()
{
std::unique_lock<std::mutex> lk(m_mtx);
assert(m_queue.empty());
while (m_tasks_running)
{
lk.unlock();
#ifndef _WIN32
usleep(1000);
#else
Sleep(1);
#endif
lk.lock();
}
}
}