mirror of
https://github.com/Pithikos/C-Thread-Pool
synced 2025-02-19 23:33:59 +03:00
Deadlocks resolved
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pithikos
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84e9a02a34
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116
thpool.c
116
thpool.c
@ -16,17 +16,11 @@
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#include <semaphore.h>
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#include <errno.h>
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#include "thpool.h" /* here you can also find the interface to each function */
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#define POLLING_INTERVAL 1
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static int thpool_keepalive = 1;
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/* Create mutex variable */
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static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; /* used to serialize queue access */
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/* Initialise thread pool */
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@ -73,6 +67,7 @@ static void thpool_thread_do(thpool_t* tp_p){
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while(thpool_keepalive){
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//printf("**** pre bsem_wait: bsem: %d, len: %d\n", tp_p->jobqueue->has_jobs->v, tp_p->jobqueue->len);
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bsem_wait(tp_p->jobqueue->has_jobs);
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if (thpool_keepalive){
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@ -81,7 +76,9 @@ static void thpool_thread_do(thpool_t* tp_p){
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void*(*func_buff)(void* arg);
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void* arg_buff;
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job_t* job_p;
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pthread_mutex_lock(&tp_p->rwmutex);
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job_p = jobqueue_pull(tp_p);
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pthread_mutex_unlock(&tp_p->rwmutex);
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if (job_p) {
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func_buff=job_p->function;
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arg_buff =job_p->arg;
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@ -92,10 +89,10 @@ static void thpool_thread_do(thpool_t* tp_p){
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}
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else
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{
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return; /* EXIT thread*/
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exit(0); /* EXIT thread*/
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}
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}
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return;
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exit(0);
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}
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@ -114,7 +111,9 @@ int thpool_add_work(thpool_t* tp_p, void *(*function_p)(void*), void* arg_p){
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newJob->arg=arg_p;
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/* add job to queue */
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pthread_mutex_lock(&tp_p->rwmutex);
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jobqueue_push(tp_p, newJob);
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pthread_mutex_unlock(&tp_p->rwmutex);
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return 0;
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}
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@ -130,43 +129,41 @@ void thpool_wait(thpool_t* tp_p){
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/* Destroy the threadpool */
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void thpool_destroy(thpool_t* tp_p){
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int t;
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/* End each thread's infinite loop */
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thpool_keepalive=0;
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/* Awake idle threads waiting at semaphore */
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thpool_keepalive = 0;
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//for (t=0; t<(tp_p->threadsN); t++){
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//bsem_post(tp_p->jobqueue->has_jobs);
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/*if (){
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fprintf(stderr, "thpool_destroy(): Could not bypass sem_wait()\n");
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}*/
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//}
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/* Wait for threads to finish */
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for (t=0; t < (tp_p->threadsN); t++){
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pthread_join(tp_p->threads[t], NULL);
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}
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jobqueue_empty(tp_p);
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//for (t=0; t < (tp_p->threadsN); t++){
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// sleep(1);
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/// bsem_post(tp_p->jobqueue->has_jobs);
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// pthread_join(tp_p->threads[t], NULL);
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//}
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/* Wait for threads to finish */
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//for (t=0; t < (tp_p->threadsN); t++){
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// pthread_join(tp_p->threads[t], NULL);
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//}
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/* Awake idle threads waiting at semaphore */
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//bsem_post(tp_p->jobqueue->has_jobs);
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//jobqueue_empty(tp_p);
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/* Dealloc */
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free(tp_p->threads);
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free(tp_p->jobqueue);
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free(tp_p);
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//free(tp_p->threads);
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//free(tp_p->jobqueue);
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//free(tp_p);
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}
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/* ===================== JOB QUEUE OPERATIONS ======================= */
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/*
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* Requirements for job queue:
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* - Thread-safe push/pull
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* - Binary semaphore for has_jobs must be 1 if there are jobs, 0 if not
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*
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* */
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/* Initialise queue */
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@ -175,25 +172,22 @@ static int jobqueue_init(thpool_t* tp_p){
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if (tp_p->jobqueue==NULL) return -1;
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tp_p->jobqueue->tail=NULL;
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tp_p->jobqueue->head=NULL;
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tp_p->jobqueue->has_jobs=(bsem_t*)malloc(sizeof(bsem_t));
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tp_p->jobqueue->has_jobs = (bsem_t*)malloc(sizeof(bsem_t));
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tp_p->jobqueue->has_jobs->v = 0;
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tp_p->jobqueue->len = 0;
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return 0;
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}
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/* How many jobs currently in queue */
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static int jobqueue_len(thpool_t* tp_p){
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return tp_p->jobqueue->len;
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}
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/* Add job to queue */
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static void jobqueue_push(thpool_t* tp_p, job_t* newjob_p){ /* remember that job prev and next point to NULL */
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pthread_mutex_lock(&mutex);
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newjob_p->next=NULL;
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switch(jobqueue_len(tp_p)){
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switch(tp_p->jobqueue->len){
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case 0: /* if there are no jobs in queue */
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tp_p->jobqueue->tail=newjob_p;
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@ -207,24 +201,20 @@ static void jobqueue_push(thpool_t* tp_p, job_t* newjob_p){ /* remember that job
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}
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tp_p->jobqueue->len++;
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bsem_post(tp_p->jobqueue->has_jobs);
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pthread_mutex_unlock(&mutex);
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}
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/* Get first element from queue */
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static job_t* jobqueue_pull(thpool_t* tp_p){
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pthread_mutex_lock(&mutex);
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//puts("**** PULLING");
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/* get first job */
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job_t* job_p;
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job_p = tp_p->jobqueue->head;
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printf(" queue length: %d\n", jobqueue_len(tp_p));
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printf(" has jobs: %d\n", tp_p->jobqueue->has_jobs->v);
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/* remove job from queue */
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switch(jobqueue_len(tp_p)){
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switch(tp_p->jobqueue->len){
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case 0: /* if there are no jobs in queue */
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return NULL;
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@ -245,22 +235,19 @@ static job_t* jobqueue_pull(thpool_t* tp_p){
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if (tp_p->jobqueue->len > 0) {
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bsem_post(tp_p->jobqueue->has_jobs);
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}
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puts(" (after pull)");
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printf(" queue length: %d\n", jobqueue_len(tp_p));
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printf(" has jobs: %d\n", tp_p->jobqueue->has_jobs->v);
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pthread_mutex_unlock(&mutex);
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return job_p;
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}
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/* Remove and deallocate all jobs in queue */
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static void jobqueue_empty(thpool_t* tp_p){
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//pthread_mutex_lock(&tp_p->jobqueue->mutex);
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job_t* curjob;
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curjob=tp_p->jobqueue->tail;
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while(jobqueue_len(tp_p)){
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while(tp_p->jobqueue->len){
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tp_p->jobqueue->tail=curjob->prev;
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free(curjob);
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curjob=tp_p->jobqueue->tail;
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@ -272,6 +259,8 @@ static void jobqueue_empty(thpool_t* tp_p){
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/* Deallocs */
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free(tp_p->jobqueue->has_jobs);
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//pthread_mutex_unlock(&tp_p->jobqueue->mutex);
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}
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@ -280,17 +269,18 @@ static void jobqueue_empty(thpool_t* tp_p){
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static void bsem_post(bsem_t *bsem) {
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pthread_mutex_lock(&bsem->mutex);
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bsem->v = 1;
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pthread_cond_signal(&bsem->cond);
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pthread_mutex_unlock(&bsem->mutex);
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pthread_mutex_lock(&bsem->mutex);
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bsem->v = 1;
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pthread_cond_signal(&bsem->cond);
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pthread_mutex_unlock(&bsem->mutex);
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}
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static void bsem_wait(bsem_t *bsem) {
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pthread_mutex_lock(&bsem->mutex);
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while (!bsem->v)
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pthread_cond_wait(&bsem->cond, &bsem->mutex);
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bsem->v = 0;
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pthread_mutex_unlock(&bsem->mutex);
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pthread_mutex_lock(&bsem->mutex);
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while (bsem->v != 1) {
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pthread_cond_wait(&bsem->cond, &bsem->mutex);
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}
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bsem->v = 0;
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pthread_mutex_unlock(&bsem->mutex);
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}
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