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/* 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_structs.h"
#include <stdlib.h>
#include <signal.h>
#include <assert.h>
#include "tpool.h"
#include <thread>
#ifdef LINUX_NATIVE_AIO
#include <libaio.h>
#endif
/*
Linux AIO implementation, based on native AIO.
Needs libaio.h and -laio at the compile time.
submit_io() is used to submit async IO.
There is a single thread, that collects the completion notification
with io_getevent(), and forwards io completion callback
the worker threadpool.
*/
namespace tpool
{
#ifdef LINUX_NATIVE_AIO
class aio_linux : public aio
{
thread_pool* m_pool;
io_context_t m_io_ctx;
bool m_in_shutdown;
std::thread m_getevent_thread;
static void getevent_thread_routine(aio_linux* aio)
{
for (;;)
{
io_event event;
struct timespec ts{0, 500000000};
int ret = io_getevents(aio->m_io_ctx, 1, 1, &event, &ts);
if (aio->m_in_shutdown)
break;
if (ret > 0)
{
aiocb* iocb = (aiocb*)event.obj;
long long res = event.res;
if (res < 0)
{
iocb->m_err = static_cast<int>(-res);
iocb->m_ret_len = 0;
}
else
{
iocb->m_ret_len = ret;
iocb->m_err = 0;
}
iocb->m_internal_task.m_func = iocb->m_callback;
iocb->m_internal_task.m_arg = iocb;
iocb->m_internal_task.m_group = iocb->m_group;
aio->m_pool->submit_task(&iocb->m_internal_task);
continue;
}
switch (ret)
{
case -EAGAIN:
usleep(1000);
continue;
case -EINTR:
case 0:
continue;
default:
fprintf(stderr, "io_getevents returned %d\n", ret);
abort();
}
}
}
public:
aio_linux(io_context_t ctx, thread_pool* pool)
: m_pool(pool), m_io_ctx(ctx),
m_in_shutdown(), m_getevent_thread(getevent_thread_routine, this)
{
}
~aio_linux()
{
m_in_shutdown = true;
m_getevent_thread.join();
io_destroy(m_io_ctx);
}
// Inherited via aio
virtual int submit_io(aiocb* cb) override
{
if (cb->m_opcode == aio_opcode::AIO_PREAD)
io_prep_pread((iocb *)cb, cb->m_fh, cb->m_buffer, cb->m_len,
cb->m_offset);
else
io_prep_pwrite((iocb *)cb, cb->m_fh, cb->m_buffer, cb->m_len,
cb->m_offset);
int ret;
ret = io_submit(m_io_ctx, 1, (iocb * *)& cb);
if (ret == 1)
return 0;
errno = -ret;
return -1;
}
// Inherited via aio
virtual int bind(native_file_handle& fd) override
{
return 0;
}
virtual int unbind(const native_file_handle& fd) override
{
return 0;
}
};
aio* create_linux_aio(thread_pool* pool, int max_io)
{
io_context_t ctx;
memset(&ctx, 0, sizeof(ctx));
int ret = io_setup(max_io, &ctx);
if (ret)
{
fprintf(stderr, "io_setup(%d) returned %d\n", max_io, ret);
return nullptr;
}
return new aio_linux(ctx, pool);
}
#else
aio* create_linux_aio(thread_pool* pool, int max_aio)
{
return nullptr;
}
#endif
}
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