Add libmthread and test59 to test the implementation
This commit is contained in:
Thomas Veerman
500
lib/libmthread/allocate.c
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500
lib/libmthread/allocate.c
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@@ -0,0 +1,500 @@
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#define ALLOCATE
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#include <errno.h>
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#include <minix/mthread.h>
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#include "global.h"
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#include "proto.h"
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#define FALLBACK_CTX (&(fallback.m_context))
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FORWARD _PROTOTYPE( void mthread_fallback, (void) );
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FORWARD _PROTOTYPE( int mthread_increase_thread_pool, (void) );
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FORWARD _PROTOTYPE( void mthread_thread_init, (mthread_thread_t thread,
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mthread_attr_t *tattr,
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void (*proc)(void *),
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void *arg) );
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FORWARD _PROTOTYPE( void mthread_thread_reset, (mthread_thread_t thread));
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FORWARD _PROTOTYPE( void mthread_thread_stop, (mthread_thread_t thread));
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FORWARD _PROTOTYPE( void mthread_trampoline, (void) );
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PRIVATE int initialized = 0;
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PRIVATE struct __mthread_attr default_attr = { MTHREAD_STACK_MIN,
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NULL,
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MTHREAD_CREATE_JOINABLE,
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NULL, NULL };
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/*===========================================================================*
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* mthread_equal *
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*===========================================================================*/
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PUBLIC int mthread_equal(l, r)
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mthread_thread_t l;
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mthread_thread_t r;
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{
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/* Compare two thread ids */
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mthread_init(); /* Make sure mthreads is initialized */
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return(l == r);
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}
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/*===========================================================================*
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* mthread_create *
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*===========================================================================*/
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PUBLIC int mthread_create(threadid, tattr, proc, arg)
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mthread_thread_t *threadid;
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mthread_attr_t *tattr;
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void (*proc)(void *);
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void *arg;
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{
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/* Register procedure proc for execution in a thread. */
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mthread_thread_t thread;
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mthread_init(); /* Make sure mthreads is initialized */
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if (proc == NULL) {
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errno = EINVAL;
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return(-1);
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}
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if (!mthread_queue_isempty(&free_threads)) {
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thread = mthread_queue_remove(&free_threads);
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mthread_thread_init(thread, tattr, proc, arg);
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used_threads++;
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if(threadid != NULL)
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*threadid = (mthread_thread_t) thread;
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#ifdef MDEBUG
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printf("Inited thread %d\n", thread);
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#endif
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return(0);
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} else {
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if (mthread_increase_thread_pool() == -1) {
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errno = EAGAIN;
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return(-1);
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}
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return mthread_create(threadid, tattr, proc, arg);
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}
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}
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/*===========================================================================*
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* mthread_detach *
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*===========================================================================*/
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PUBLIC int mthread_detach(detach)
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mthread_thread_t detach;
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{
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/* Mark a thread as detached. Consequently, upon exit, resources allocated for
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* this thread are automatically freed.
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*/
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mthread_init(); /* Make sure mthreads is initialized */
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if (!isokthreadid(detach)) {
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errno = ESRCH;
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return(-1);
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} else if (threads[detach].m_state == DEAD) {
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errno = ESRCH;
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return(-1);
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} else if (threads[detach].m_attr.a_detachstate != MTHREAD_CREATE_DETACHED) {
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if (threads[detach].m_state == EXITING) {
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mthread_thread_stop(detach);
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} else {
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threads[detach].m_attr.a_detachstate = MTHREAD_CREATE_DETACHED;
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}
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}
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return(0);
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}
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/*===========================================================================*
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* mthread_exit *
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*===========================================================================*/
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PUBLIC void mthread_exit(value)
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void *value;
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{
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/* Make a thread stop running and store the result value. */
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int fallback_exit = 0;
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mthread_thread_t stop;
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mthread_init(); /* Make sure mthreads is initialized */
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stop = current_thread;
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if (threads[stop].m_state == EXITING) /* Already stopping, nothing to do. */
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return;
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/* When we're called from the fallback thread, the fallback thread
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* will invoke the scheduler. However, if the thread itself called
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* mthread_exit, _we_ will have to wake up the scheduler.
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*/
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if (threads[stop].m_state == FALLBACK_EXITING)
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fallback_exit = 1;
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threads[stop].m_result = value;
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threads[stop].m_state = EXITING;
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if (threads[stop].m_attr.a_detachstate == MTHREAD_CREATE_DETACHED) {
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mthread_thread_stop(stop);
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} else {
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/* Joinable thread; notify possibly waiting thread */
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if (mthread_cond_signal(&(threads[stop].m_exited)) != 0)
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mthread_panic("Couldn't signal exit");
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/* The thread that's actually doing the join will eventually clean
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* up this thread (i.e., call mthread_thread_stop).
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*/
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}
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/* The fallback thread does a mthread_schedule. If we're not running from
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* that thread, we have to do it ourselves.
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*/
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if (!fallback_exit)
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mthread_schedule();
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}
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/*===========================================================================*
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* mthread_fallback *
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*===========================================================================*/
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PRIVATE void mthread_fallback(void)
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{
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/* The mthreads fallback thread. The idea is that every thread calls
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* mthread_exit(...) to stop running when it has nothing to do anymore.
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* However, in case a thread forgets to do that, the whole process exit()s and
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* that might be a bit problematic. Therefore, all threads will run this
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* fallback thread when they exit, giving the scheduler a chance to fix the
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* situation.
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*/
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threads[current_thread].m_state = FALLBACK_EXITING;
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mthread_exit(NULL);
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/* Reconstruct fallback context for next invocation */
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makecontext(FALLBACK_CTX, (void (*) (void)) mthread_fallback, 0);
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/* Let another thread run */
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mthread_schedule();
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}
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/*===========================================================================*
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* mthread_increase_thread_pool *
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*===========================================================================*/
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PRIVATE int mthread_increase_thread_pool(void)
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{
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/* Increase thread pool. No fancy algorithms, just double the size. */
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mthread_tcb_t *new_tcb;
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int new_no_threads, old_no_threads, i;
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old_no_threads = no_threads;
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new_no_threads = 2 * old_no_threads;
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if (new_no_threads >= MAX_THREAD_POOL) {
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mthread_debug("Reached max number of threads");
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return(-1);
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}
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new_tcb = realloc(threads, new_no_threads * sizeof(mthread_tcb_t));
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if (new_tcb == NULL) {
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mthread_debug("Can't increase thread pool");
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return(-1);
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}
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threads = new_tcb;
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no_threads = new_no_threads;
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/* Add newly available threads to free_threads */
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for (i = old_no_threads; i < new_no_threads; i++) {
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mthread_queue_add(&free_threads, i);
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mthread_thread_reset(i);
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}
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#ifdef MDEBUG
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printf("Increased thread pool from %d to %d threads\n", no_threads, new_no_threads);
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#endif
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return(0);
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}
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/*===========================================================================*
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* mthread_init *
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*===========================================================================*/
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PUBLIC void mthread_init(void)
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{
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/* Initialize thread system; allocate thread structures and start creating
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* threads.
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*/
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if (!initialized) {
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int i;
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no_threads = NO_THREADS;
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used_threads = 0;
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running_main_thread = 1;/* mthread_init can only be called from the
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* main thread. Calling it from a thread will
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* not enter this clause.
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*/
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if (getcontext(&(mainthread.m_context)) == -1)
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mthread_panic("Couldn't save state for main thread");
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current_thread = NO_THREAD;
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/* Allocate a bunch of thread control blocks */
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threads = malloc(no_threads * sizeof(mthread_tcb_t));
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if (threads == NULL)
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mthread_panic("No memory, can't initialize threads");
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mthread_init_valid_mutexes();
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mthread_init_valid_conditions();
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mthread_init_valid_attributes();
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mthread_init_scheduler();
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/* Put initial threads on the free threads queue */
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mthread_queue_init(&free_threads);
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for (i = 0; i < no_threads; i++) {
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mthread_queue_add(&free_threads, i);
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mthread_thread_reset(i);
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}
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/* Initialize the fallback thread */
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if (getcontext(FALLBACK_CTX) == -1)
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mthread_panic("Could not initialize fallback thread");
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FALLBACK_CTX->uc_link = &(mainthread.m_context);
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FALLBACK_CTX->uc_stack.ss_sp = malloc(STACKSZ);
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FALLBACK_CTX->uc_stack.ss_size = STACKSZ;
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if (FALLBACK_CTX->uc_stack.ss_sp == NULL)
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mthread_panic("Could not allocate stack space to fallback "
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"thread");
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makecontext(FALLBACK_CTX, (void (*) (void)) mthread_fallback, 0);
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initialized = 1;
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}
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}
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/*===========================================================================*
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* mthread_join *
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*===========================================================================*/
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PUBLIC int mthread_join(join, value)
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mthread_thread_t join;
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void **value;
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{
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/* Wait for a thread to stop running and copy the result. */
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mthread_init(); /* Make sure mthreads is initialized */
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if (!isokthreadid(join)) {
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errno = ESRCH;
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return(-1);
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} else if (join == current_thread) {
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errno = EDEADLK;
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return(-1);
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} else if (threads[join].m_state == DEAD) {
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errno = ESRCH;
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return(-1);
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} else if (threads[join].m_attr.a_detachstate == MTHREAD_CREATE_DETACHED) {
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errno = EINVAL;
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return(-1);
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}
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/* When the thread hasn't exited yet, we have to wait for that to happen */
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if (threads[join].m_state != EXITING) {
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mthread_cond_t *c;
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mthread_mutex_t *m;
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c = &(threads[join].m_exited);
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m = &(threads[join].m_exitm);
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if (mthread_mutex_init(m, NULL) != 0)
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mthread_panic("Couldn't initialize mutex to join\n");
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if (mthread_mutex_lock(m) != 0)
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mthread_panic("Couldn't lock mutex to join\n");
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if (mthread_cond_wait(c, m) != 0)
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mthread_panic("Couldn't wait for join condition\n");
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if (mthread_mutex_unlock(m) != 0)
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mthread_panic("Couldn't unlock mutex to join\n");
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if (mthread_mutex_destroy(m) != 0)
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mthread_panic("Couldn't destroy mutex to join\n");
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}
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/* Thread has exited; copy results */
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if(value != NULL)
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*value = threads[join].m_result;
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/* Deallocate resources */
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mthread_thread_stop(join);
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return(0);
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}
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/*===========================================================================*
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* mthread_once *
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*===========================================================================*/
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PUBLIC int mthread_once(once, proc)
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mthread_once_t *once;
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void (*proc)(void);
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{
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/* Run procedure proc just once */
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mthread_init(); /* Make sure mthreads is initialized */
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if (once == NULL || proc == NULL) {
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errno = EINVAL;
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return(-1);
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}
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if (*once != 1) proc();
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*once = 1;
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return(0);
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}
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/*===========================================================================*
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* mthread_self *
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*===========================================================================*/
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PUBLIC mthread_thread_t mthread_self(void)
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{
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/* Return the thread id of the thread calling this function. */
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mthread_init(); /* Make sure mthreads is initialized */
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return(current_thread);
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}
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/*===========================================================================*
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* mthread_thread_init *
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*===========================================================================*/
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PRIVATE void mthread_thread_init(thread, tattr, proc, arg)
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mthread_thread_t thread;
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mthread_attr_t *tattr;
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void (*proc)(void *);
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void *arg;
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{
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/* Initialize a thread so that it, when unsuspended, will run the given
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* procedure with the given parameter. The thread is marked as runnable.
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*/
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#define THIS_CTX (&(threads[thread].m_context))
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size_t stacksize;
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char *stackaddr;
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threads[thread].m_next = NO_THREAD;
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threads[thread].m_state = DEAD;
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threads[thread].m_proc = (void *(*)(void *)) proc; /* Yikes */
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threads[thread].m_arg = arg;
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/* Threads use a copy of the provided attributes. This way, if another
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* thread modifies the attributes (such as detach state), already running
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* threads are not affected.
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*/
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if (tattr != NULL)
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threads[thread].m_attr = *((struct __mthread_attr *) *tattr);
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else {
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threads[thread].m_attr = default_attr;
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}
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if (mthread_cond_init(&(threads[thread].m_exited), NULL) != 0)
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mthread_panic("Could not initialize thread");
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/* First set the fallback thread, */
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THIS_CTX->uc_link = FALLBACK_CTX;
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/* then construct this thread's context to run procedure proc. */
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if (getcontext(THIS_CTX) == -1)
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mthread_panic("Failed to initialize context state");
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stacksize = threads[thread].m_attr.a_stacksize;
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stackaddr = threads[thread].m_attr.a_stackaddr;
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if (stacksize == (size_t) 0)
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stacksize = (size_t) MTHREAD_STACK_MIN;
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if (stackaddr == NULL) {
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/* Allocate stack space */
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THIS_CTX->uc_stack.ss_sp = malloc(stacksize);
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if (THIS_CTX->uc_stack.ss_sp == NULL)
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mthread_panic("Failed to allocate stack to thread");
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} else
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THIS_CTX->uc_stack.ss_sp = stackaddr;
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THIS_CTX->uc_stack.ss_size = stacksize;
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makecontext(THIS_CTX, mthread_trampoline, 0);
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mthread_unsuspend(thread); /* Make thread runnable */
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}
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/*===========================================================================*
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* mthread_thread_reset *
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*===========================================================================*/
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PRIVATE void mthread_thread_reset(thread)
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mthread_thread_t thread;
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{
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/* Reset the thread to its default values. Free the allocated stack space. */
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mthread_tcb_t *rt;
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if (!isokthreadid(thread)) mthread_panic("Invalid thread id");
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rt = &(threads[thread]);
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rt->m_next = NO_THREAD;
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rt->m_state = DEAD;
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rt->m_proc = NULL;
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rt->m_arg = NULL;
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rt->m_result = NULL;
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rt->m_cond = NULL;
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if (rt->m_context.uc_stack.ss_sp)
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free(rt->m_context.uc_stack.ss_sp); /* Free allocated stack */
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rt->m_context.uc_stack.ss_sp = NULL;
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rt->m_context.uc_stack.ss_size = 0;
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rt->m_context.uc_link = NULL;
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}
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/*===========================================================================*
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* mthread_thread_stop *
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*===========================================================================*/
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PRIVATE void mthread_thread_stop(thread)
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mthread_thread_t thread;
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{
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/* Stop thread from running. Deallocate resources. */
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mthread_tcb_t *stop_thread;
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if (!isokthreadid(thread)) mthread_panic("Invalid thread id");
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stop_thread = &(threads[thread]);
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if (stop_thread->m_state == DEAD) {
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/* Already DEAD, nothing to do */
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return;
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}
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mthread_thread_reset(thread);
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if (mthread_cond_destroy(&(stop_thread->m_exited)) != 0)
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mthread_panic("Could not destroy condition at thread deallocation\n");
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used_threads--;
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mthread_queue_add(&free_threads, thread);
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}
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/*===========================================================================*
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* mthread_trampoline *
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*===========================================================================*/
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PRIVATE void mthread_trampoline(void)
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{
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/* Execute the /current_thread's/ procedure. Store its result. */
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void *r;
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r = (threads[current_thread].m_proc)(threads[current_thread].m_arg);
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mthread_exit(r);
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}
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