| 0,0 → 1,310 |
|---|
| /* |
| * 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 uspace 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 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--; |
| } |
| |
| |
| /** @} |
| */ |