0,0 → 1,308 |
/* |
* Copyright (C) 2006 Ondrej Palkovsky |
* All rights reserved. |
* |
* Redistribution and use in source and binary forms, with or without |
* modification, are permitted provided that the following conditions |
* are met: |
* |
* - Redistributions of source code must retain the above copyright |
* notice, this list of conditions and the following disclaimer. |
* - Redistributions in binary form must reproduce the above copyright |
* notice, this list of conditions and the following disclaimer in the |
* documentation and/or other materials provided with the distribution. |
* - The name of the author may not be used to endorse or promote products |
* derived from this software without specific prior written permission. |
* |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
*/ |
|
/** @addtogroup libc |
* @{ |
*/ |
/** @file |
*/ |
|
#include <libadt/list.h> |
#include <psthread.h> |
#include <malloc.h> |
#include <unistd.h> |
#include <thread.h> |
#include <stdio.h> |
#include <libarch/faddr.h> |
#include <futex.h> |
#include <assert.h> |
#include <async.h> |
|
#ifndef PSTHREAD_INITIAL_STACK_PAGES_NO |
#define PSTHREAD_INITIAL_STACK_PAGES_NO 1 |
#endif |
|
static LIST_INITIALIZE(ready_list); |
static LIST_INITIALIZE(serialized_list); |
static LIST_INITIALIZE(manager_list); |
|
static void psthread_main(void); |
|
static atomic_t psthread_futex = FUTEX_INITIALIZER; |
/** Count of real threads that are in async_serialized mode */ |
static int serialized_threads; /* Protected by async_futex */ |
/** Thread-local count of serialization. If >0, we must not preempt */ |
static __thread int serialization_count; |
/** Counter of threads residing in async_manager */ |
static int threads_in_manager; |
|
/** Setup psthread information into TCB structure */ |
psthread_data_t * psthread_setup() |
{ |
psthread_data_t *pt; |
tcb_t *tcb; |
|
tcb = __make_tls(); |
if (!tcb) |
return NULL; |
|
pt = malloc(sizeof(*pt)); |
if (!pt) { |
__free_tls(tcb); |
return NULL; |
} |
|
tcb->pst_data = pt; |
pt->tcb = tcb; |
|
return pt; |
} |
|
void psthread_teardown(psthread_data_t *pt) |
{ |
__free_tls(pt->tcb); |
free(pt); |
} |
|
/** Function that is called on entry to new pseudo thread */ |
void psthread_main(void) |
{ |
psthread_data_t *pt = __tcb_get()->pst_data; |
|
pt->retval = pt->func(pt->arg); |
|
pt->finished = 1; |
if (pt->waiter) |
list_append(&pt->waiter->link, &ready_list); |
|
psthread_schedule_next_adv(PS_FROM_DEAD); |
} |
|
/** Schedule next userspace pseudo thread. |
* |
* If calling with PS_TO_MANAGER parameter, the async_futex should be |
* held. |
* |
* @param ctype Type of switch. |
* @return 0 if there is no ready pseudo thread, 1 otherwise. |
*/ |
int psthread_schedule_next_adv(pschange_type ctype) |
{ |
psthread_data_t *srcpt, *dstpt; |
int retval = 0; |
|
futex_down(&psthread_futex); |
|
if (ctype == PS_PREEMPT && list_empty(&ready_list)) |
goto ret_0; |
|
if (ctype == PS_FROM_MANAGER) { |
if (list_empty(&ready_list) && list_empty(&serialized_list)) |
goto ret_0; |
/* Do not preempt if there is not sufficient count of thread managers */ |
if (list_empty(&serialized_list) && threads_in_manager <= serialized_threads) { |
goto ret_0; |
} |
} |
/* If we are going to manager and none exists, create it */ |
if (ctype == PS_TO_MANAGER || ctype == PS_FROM_DEAD) { |
while (list_empty(&manager_list)) { |
futex_up(&psthread_futex); |
async_create_manager(); |
futex_down(&psthread_futex); |
} |
} |
|
if (ctype != PS_FROM_DEAD) { |
/* Save current state */ |
srcpt = __tcb_get()->pst_data; |
if (!context_save(&srcpt->ctx)) { |
if (serialization_count) |
srcpt->flags &= ~PSTHREAD_SERIALIZED; |
return 1; // futex_up already done here |
} |
|
/* Save myself to correct run list */ |
if (ctype == PS_PREEMPT) |
list_append(&srcpt->link, &ready_list); |
else if (ctype == PS_FROM_MANAGER) { |
list_append(&srcpt->link, &manager_list); |
threads_in_manager--; |
} /* If ctype == PS_TO_MANAGER, don't save ourselves to any list, we should |
* already be somewhere, or we will be lost */ |
} else |
srcpt = NULL; /* Avoid GCC warning, if ctype == PS_FROM_DEAD, srcpt is not used */ |
|
/* Choose new thread to run */ |
if (ctype == PS_TO_MANAGER || ctype == PS_FROM_DEAD) { |
dstpt = list_get_instance(manager_list.next,psthread_data_t, link); |
if (serialization_count && ctype == PS_TO_MANAGER) { |
serialized_threads++; |
srcpt->flags |= PSTHREAD_SERIALIZED; |
} |
threads_in_manager++; |
} else { |
if (!list_empty(&serialized_list)) { |
dstpt = list_get_instance(serialized_list.next, psthread_data_t, link); |
serialized_threads--; |
} else |
dstpt = list_get_instance(ready_list.next, psthread_data_t, link); |
} |
list_remove(&dstpt->link); |
|
futex_up(&psthread_futex); |
context_restore(&dstpt->ctx); |
|
ret_0: |
futex_up(&psthread_futex); |
return retval; |
} |
|
/** Wait for uspace pseudo thread to finish. |
* |
* @param psthrid Pseudo thread to wait for. |
* |
* @return Value returned by the finished thread. |
*/ |
int psthread_join(pstid_t psthrid) |
{ |
volatile psthread_data_t *pt; |
volatile int retval; |
|
/* Handle psthrid = Kernel address -> it is wait for call */ |
pt = (psthread_data_t *) psthrid; |
|
/* TODO */ |
printf("join unsupported\n"); |
_exit(1); |
|
retval = pt->retval; |
|
free(pt->stack); |
psthread_teardown((void *)pt); |
|
return retval; |
} |
|
/** Create a userspace pseudo thread. |
* |
* @param func Pseudo thread function. |
* @param arg Argument to pass to func. |
* |
* @return 0 on failure, TLS of the new pseudo thread. |
*/ |
pstid_t psthread_create(int (*func)(void *), void *arg) |
{ |
psthread_data_t *pt; |
|
pt = psthread_setup(); |
if (!pt) |
return 0; |
pt->stack = (char *) malloc(PSTHREAD_INITIAL_STACK_PAGES_NO*getpagesize()); |
|
if (!pt->stack) { |
psthread_teardown(pt); |
return 0; |
} |
|
pt->arg= arg; |
pt->func = func; |
pt->finished = 0; |
pt->waiter = NULL; |
pt->flags = 0; |
|
context_save(&pt->ctx); |
context_set(&pt->ctx, FADDR(psthread_main), pt->stack, PSTHREAD_INITIAL_STACK_PAGES_NO*getpagesize(), pt->tcb); |
|
return (pstid_t )pt; |
} |
|
/** Add a thread to ready list */ |
void psthread_add_ready(pstid_t psthrid) |
{ |
psthread_data_t *pt; |
|
pt = (psthread_data_t *) psthrid; |
futex_down(&psthread_futex); |
if ((pt->flags & PSTHREAD_SERIALIZED)) |
list_append(&pt->link, &serialized_list); |
else |
list_append(&pt->link, &ready_list); |
futex_up(&psthread_futex); |
} |
|
/** Add a thread to manager list */ |
void psthread_add_manager(pstid_t psthrid) |
{ |
psthread_data_t *pt; |
|
pt = (psthread_data_t *) psthrid; |
|
futex_down(&psthread_futex); |
list_append(&pt->link, &manager_list); |
futex_up(&psthread_futex); |
} |
|
/** Remove one manager from manager list */ |
void psthread_remove_manager() |
{ |
futex_down(&psthread_futex); |
if (list_empty(&manager_list)) { |
futex_up(&psthread_futex); |
return; |
} |
list_remove(manager_list.next); |
futex_up(&psthread_futex); |
} |
|
/** Return thread id of current running thread */ |
pstid_t psthread_get_id(void) |
{ |
return (pstid_t)__tcb_get()->pst_data; |
} |
|
/** Disable preemption |
* |
* If the thread wants to send several message in row and does not want |
* to be preempted, it should start async_serialize_start() in the beginning |
* of communication and async_serialize_end() in the end. If it is a |
* true multithreaded application, it should protect the communication channel |
* by a futex as well. Interrupt messages will can still be preempted. |
*/ |
void psthread_inc_sercount(void) |
{ |
serialization_count++; |
} |
|
void psthread_dec_sercount(void) |
{ |
serialization_count--; |
} |
|
/** @} |
*/ |