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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.
*/
/* clang-format off */
#include "preamble.h"
/* `read` not in preamble because we specialize for reading-into a uint64_t
var (as used by `s_process_task_pre_queue`) */
ssize_t read(int fd, void *buf, uint64_t count)
_(requires valid_fd(fd))
_(requires count == sizeof(uint64_t))
_(writes (uint64_t *)buf)
;
static void s_process_task_pre_queue(struct aws_event_loop *event_loop _(ghost \claim(c_event_loop)) _(ghost \claim(c_mutex))) {
_(assert \always_by_claim(c_event_loop, event_loop))
struct epoll_loop *epoll_loop = event_loop->impl_data;
_(assert \inv(epoll_loop))
if (!epoll_loop->should_process_task_pre_queue) {
return;
}
AWS_LOGF_TRACE(AWS_LS_IO_EVENT_LOOP, "id=%p: processing cross-thread tasks", (void *)event_loop);
epoll_loop->should_process_task_pre_queue = false;
struct aws_linked_list task_pre_queue;
aws_linked_list_init(&task_pre_queue);
_(wrap(&task_pre_queue.head))
_(wrap(&task_pre_queue.tail))
_(wrap(&task_pre_queue))
uint64_t count_ignore = 0;
aws_mutex_lock(&epoll_loop->task_pre_queue_mutex _(ghost c_mutex));
/* several tasks could theoretically have been written (though this should never happen), make sure we drain the
* eventfd/pipe. */
while (read(epoll_loop->read_task_handle.data.fd, &count_ignore, sizeof(count_ignore)) > -1)
_(invariant \thread_local(&epoll_loop->read_task_handle))
_(invariant (&epoll_loop->read_task_handle)->\closed)
_(invariant \inv(&epoll_loop->read_task_handle))
_(invariant \wrapped(&epoll_loop->scheduler))
_(writes &count_ignore)
{
}
aws_linked_list_swap_contents(&epoll_loop->task_pre_queue, &task_pre_queue);
aws_mutex_unlock(&epoll_loop->task_pre_queue_mutex _(ghost c_mutex));
while (!aws_linked_list_empty(&task_pre_queue))
_(invariant 0 <= task_pre_queue.length)
_(invariant \wrapped(&task_pre_queue))
_(invariant \wrapped(&epoll_loop->scheduler))
_(writes &task_pre_queue, &epoll_loop->scheduler)
{
_(ghost struct aws_task *t)
struct aws_linked_list_node *node = aws_linked_list_pop_front(&task_pre_queue _(out t));
struct aws_task *task = AWS_CONTAINER_OF(node, struct aws_task, node);
AWS_LOGF_TRACE(
AWS_LS_IO_EVENT_LOOP,
"id=%p: task %p pulled to event-loop, scheduling now.",
(void *)event_loop,
(void *)task);
/* Timestamp 0 is used to denote "now" tasks */
if (task->timestamp == 0) {
aws_task_scheduler_schedule_now(&epoll_loop->scheduler, task);
} else {
aws_task_scheduler_schedule_future(&epoll_loop->scheduler, task, task->timestamp);
}
}
_(unwrap(&task_pre_queue))
_(unwrap(&task_pre_queue.head))
_(unwrap(&task_pre_queue.tail))
}
/* clang-format on */
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