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/* fiber.c - fiber management and scheduling
*
* Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 or later as
* published by the Free Software Foundation.
*
* See http://www.gnu.org/ for details.
*/
#include <errno.h>
#include <libtf/tf.h>
#include TF_UCTX_H
struct tf_scheduler {
struct tf_list_head run_q;
struct tf_list_head sleep_q;
struct tf_fiber * active_fiber;
int num_fibers;
};
/* FIXME: should be in thread local storage */
static struct tf_scheduler *__scheduler;
void *tf_fiber_create(tf_fiber_proc fiber_main, int private_size)
{
struct tf_scheduler *sched = __scheduler;
struct tf_fiber *fiber;
fiber = tf_uctx_create(fiber_main, private_size);
/* The initial references for caller and scheduler */
*fiber = (struct tf_fiber) {
.ref_count = 2,
.queue_node = TF_LIST_INITIALIZER(fiber->queue_node),
};
tf_list_add_tail(&fiber->queue_node, &sched->run_q);
sched->num_fibers++;
return fiber->data;
}
void __tf_fiber_destroy(struct tf_fiber *fiber)
{
tf_uctx_destroy(fiber);
}
void *tf_fiber_get(void *data)
{
struct tf_fiber *fiber = container_of(data, struct tf_fiber, data);
tf_atomic_inc(fiber->ref_count);
return data;
}
void tf_fiber_put(void *data)
{
struct tf_fiber *fiber = container_of(data, struct tf_fiber, data);
if (tf_atomic_dec(fiber->ref_count) == 0)
__tf_fiber_destroy(fiber);
}
static void run_fiber(void)
{
struct tf_scheduler *sched = __scheduler;
struct tf_fiber *schedf = container_of((void*) __scheduler, struct tf_fiber, data);
struct tf_fiber *f;
if (tf_list_empty(&sched->run_q))
return;
f = tf_list_first(&sched->run_q, struct tf_fiber, queue_node);
tf_list_del(&f->queue_node);
sched->active_fiber = f;
switch (tf_uctx_transfer(schedf, f, 1)) {
case EFAULT: /* Fiber is dead */
tf_fiber_put(f->data);
sched->num_fibers--;
break;
case EAGAIN: /* Yielded, reshedule */
tf_list_add_tail(&f->queue_node, &sched->run_q);
break;
case EIO: /* Blocked, in sleep */
tf_list_add_tail(&f->queue_node, &sched->sleep_q);
break;
default:
TF_BUG_ON("bad scheduler call from fiber");
}
}
int tf_main(tf_fiber_proc main_fiber)
{
struct tf_uctx *ctx = alloca(sizeof(struct tf_uctx) + sizeof(struct tf_scheduler));
struct tf_scheduler *sched = (struct tf_scheduler*) ctx->fiber.data;
int stack_guard = STACK_GUARD;
ctx->stack_guard = &stack_guard;
*sched = (struct tf_scheduler){
.run_q = TF_LIST_HEAD_INITIALIZER(sched->run_q),
.sleep_q = TF_LIST_HEAD_INITIALIZER(sched->sleep_q),
};
__scheduler = sched;
tf_fiber_put(tf_fiber_create(main_fiber, 0));
do {
run_fiber();
} while (likely(sched->num_fibers));
__scheduler = NULL;
return 0;
}
int tf_schedule(int err)
{
struct tf_scheduler *sched = __scheduler;
struct tf_fiber *schedf = container_of((void*) __scheduler, struct tf_fiber, data);
struct tf_fiber *f = sched->active_fiber;
int r;
r = tf_uctx_transfer(f, schedf, err);
if (r == 1)
return 0;
return r;
}
void tf_kill(void *fiber)
{
}
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