fix: remove malloc in mutex and update tests

This commit is contained in:
Nemo D'ACREMONT 2025-04-04 16:52:14 +02:00
parent 1aeb759d77
commit e45992ac9d
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GPG Key ID: 85F245EC3BB1E022
5 changed files with 35 additions and 70 deletions

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@ -29,7 +29,7 @@ install_bins_targets+=${install_dir}/bin/51-fibonacci
valgrind_targets=$(addprefix valgrind_,${bins})
check_argv?=8 255
check_argv?=20 255
check_targets=$(addprefix check_,${bins})
src_dirs=$(sort $(dir $(wildcard ${src_dir}/**/)))
@ -88,7 +88,7 @@ valgrind: ${valgrind_targets}
.PHONY: ${valgrind_targets}
${valgrind_targets}: valgrind_%: ${build_dir}/%
valgrind $^ --leak-check=full --show-reachable=yes --track-origins=yes
valgrind $^ ${check_argv} --leak-check=full --show-reachable=yes --track-origins=yes
.PHONY: build
build: ${bins_target} ${build_dir}/libthread.so ${build_dir}/libthread.a

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@ -35,11 +35,6 @@
#define STACK_SIZE 4096
#endif
// Variables used to clean up everything at the end of the processes
#ifndef HASHMAP_SIZE
#define HASHMAP_SIZE 16384
#endif
// Variables used to clean up everything at the end of the processus
static char stack_for_freeing[STACK_SIZE] = {0};
static int stack_valgrind_id = 0;
@ -54,7 +49,7 @@ struct context_entry {
ucontext_t context;
void *retvalue; // return value or if the thread is waited, the id of the thread that wait for it
struct last_thread_t *last_waited;
struct mutex_fifo_entry_t* mutex_fifo_entry;
struct mutex_fifo_entry_t mutex_fifo_entry;
int valgrind_id;
char status;
char stack[STACK_SIZE];
@ -76,12 +71,6 @@ static TAILQ_HEAD(freed_context_head, context_entry) context_to_freed = TAILQ_HE
static STAILQ_HEAD(last_thread_head, last_thread_t) last_thread_freed = STAILQ_HEAD_INITIALIZER(last_thread_freed);
struct mutex_fifo_entry_t {
STAILQ_ENTRY(mutex_fifo_entry_t) link;
struct context_entry* thread;
};
STAILQ_HEAD(mutex_fifo, mutex_fifo_entry_t) mutex_fifo;
static struct mutex_fifo* mutex_fifo_hashmap[HASHMAP_SIZE] = {};
int thread_yield(void)
{
@ -165,7 +154,6 @@ int thread_create(thread_t* newthread, void* (*func)(void*), void* funcarg)
new_entry->status = ALLOCATED;
new_entry->retvalue = NULL;
new_entry->last_waited = NULL;
new_entry->mutex_fifo_entry = NULL;
*newthread = new_entry;
@ -239,7 +227,7 @@ int thread_join(thread_t thread, void** retval)
}
}
DBG("%p is waiting for %p", running, entry);
DBG("MUTEX WAITING %d", IS_MUTEX_WAITING(GET_LAST_WAITED_THREAD(running)));
@ -315,7 +303,6 @@ void clear_context(void)
while (!TAILQ_EMPTY(&head)) {
last = TAILQ_FIRST(&head);
TAILQ_REMOVE(&head, last, link);
free(last->mutex_fifo_entry);
if (WAS_ALLOCATED(last)) {
VALGRIND_STACK_DEREGISTER(last->valgrind_id);
}
@ -327,7 +314,6 @@ void clear_context(void)
}
while (!TAILQ_EMPTY(&context_to_freed)) {
last = TAILQ_FIRST(&context_to_freed);
free(last->mutex_fifo_entry);
TAILQ_REMOVE(&context_to_freed, last, link);
if (WAS_ALLOCATED(last)) {
VALGRIND_STACK_DEREGISTER(last->valgrind_id);
@ -342,10 +328,6 @@ void clear_context(void)
free(last_thread);
}
// Free all the fifo that might have been allocated
for (int i = 0 ; i < HASHMAP_SIZE ; ++i)
free(mutex_fifo_hashmap[i]);
VALGRIND_STACK_DEREGISTER(stack_valgrind_id);
exit(0);
}
@ -361,7 +343,6 @@ void __attribute__((constructor)) setup_main_thread()
main->valgrind_id = 0;
main->retvalue = NULL;
main->last_waited = NULL;
main->mutex_fifo_entry = NULL;
running = main;
// Create a context with static stack to clean everything at the end.
@ -390,45 +371,28 @@ void __attribute__((destructor)) clear_last_thread()
int thread_mutex_init(thread_mutex_t* mutex)
{
long id = ((long)mutex) % HASHMAP_SIZE;
if (mutex_fifo_hashmap[id] == NULL)
{
mutex_fifo_hashmap[id] = malloc(sizeof(mutex_fifo));
STAILQ_INIT(mutex_fifo_hashmap[id]);
}
STAILQ_INIT(&mutex->fifo);
return mutex->dummy = 0;
}
int thread_mutex_destroy(thread_mutex_t* mutex)
{
long id = ((long)mutex) % HASHMAP_SIZE;
struct mutex_fifo_entry_t* last = NULL;
while (!STAILQ_EMPTY(mutex_fifo_hashmap[id])) {
last = STAILQ_FIRST(mutex_fifo_hashmap[id]);
STAILQ_REMOVE_HEAD(mutex_fifo_hashmap[id], link);
free(last);
}
return 0;
}
int thread_mutex_lock(thread_mutex_t* mutex)
{
// Add to mutex fifo
long id = ((long)mutex) % HASHMAP_SIZE;
DBG("Lock mutex %d\n", id);
DBG("Lock mutex %p\n", mutex);
while (! __sync_bool_compare_and_swap(&mutex->dummy, 0, 1))
{
DBG("Wait for mutex %d\n", id);
if (running->mutex_fifo_entry == NULL)
running->mutex_fifo_entry = malloc(sizeof(struct mutex_fifo_entry_t));
DBG("Wait for mutex %p\n", mutex);
STAILQ_INSERT_TAIL(&mutex->fifo, &running->mutex_fifo_entry, link);
STAILQ_INSERT_TAIL(mutex_fifo_hashmap[id], running->mutex_fifo_entry, link);
// Use status to be in waiting state
SET_STATUS(running, MUTEX_WAITING);
running->mutex_fifo_entry->thread = running;
running->mutex_fifo_entry.thread = running;
thread_yield();
}
@ -438,12 +402,11 @@ int thread_mutex_lock(thread_mutex_t* mutex)
int thread_mutex_unlock(thread_mutex_t* mutex)
{
long id = ((long)mutex) % HASHMAP_SIZE;
DBG("Unlock mutex %d\n", id);
if (!STAILQ_EMPTY(mutex_fifo_hashmap[id]))
DBG("Unlock mutex %p\n", mutex);
if (!STAILQ_EMPTY(&mutex->fifo))
{
struct mutex_fifo_entry_t* first = STAILQ_FIRST(mutex_fifo_hashmap[id]);
STAILQ_REMOVE_HEAD(mutex_fifo_hashmap[id], link);
struct mutex_fifo_entry_t* first = STAILQ_FIRST(&mutex->fifo);
STAILQ_REMOVE_HEAD(&mutex->fifo, link);
UNSET_STATUS(first->thread, MUTEX_WAITING);
TAILQ_INSERT_TAIL(&head, first->thread, link);

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@ -2,6 +2,7 @@
#define __THREAD_H__
#ifndef USE_PTHREAD
#include <sys/queue.h>
/* identifiant de thread
* NB: pourra être un entier au lieu d'un pointeur si ca vous arrange,
@ -40,7 +41,12 @@ extern int thread_join(thread_t thread, void **retval);
extern void thread_exit(void *retval) __attribute__ ((__noreturn__));
/* Interface possible pour les mutex */
typedef struct thread_mutex { int dummy; } thread_mutex_t;
struct mutex_fifo_entry_t {
STAILQ_ENTRY(mutex_fifo_entry_t) link;
struct context_entry* thread;
};
STAILQ_HEAD(mutex_fifo_t, mutex_fifo_entry_t);
typedef struct thread_mutex { int dummy; struct mutex_fifo_t fifo; } thread_mutex_t;
int thread_mutex_init(thread_mutex_t *mutex);
int thread_mutex_destroy(thread_mutex_t *mutex);
int thread_mutex_lock(thread_mutex_t *mutex);

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@ -7,13 +7,14 @@
#include "thread.h"
/* test pour verifier que prendre un mutex ne desactive pas l'equité envers les autres threads.
* si ca deadlock, c'est qu'il y a un problème.
* la durée du test n'est pas clairement utilisable pour juger de l'équité.
*
* valgrind doit etre content.
* Le programme doit finir.
*
* support nécessaire:
* - thread_create()
* - retour sans thread_exit()
* - thread_join() sans récupération de la valeur de retour
* - thread_mutex_init()
* - thread_mutex_destroy()
@ -30,14 +31,17 @@ static void * thfunc(void *dummy __attribute__((unused)))
/* on incremente progressivement fini jusque 5 pour debloquer le main */
for(i=0; i<5; i++) {
printf(" le fils yield sans le mutex et incrémente le compteur %u\n", fini);
thread_yield();
fini++;
}
/* on attend que main remette à 0 */
thread_mutex_lock(&lock);
while (fini != 0)
while (fini != 0) {
printf(" le fils yield avec le mutex en attendant que le compteur %u soit 0\n", fini);
thread_yield();
}
thread_mutex_unlock(&lock);
thread_exit(NULL);
@ -47,10 +51,6 @@ int main(void)
{
thread_t th;
int err, i;
struct timeval tv1, tv2;
unsigned long us;
gettimeofday(&tv1, NULL);
/* on cree le mutex et le thread */
if (thread_mutex_init(&lock) != 0) {
@ -62,12 +62,15 @@ int main(void)
/* on prend le lock puis on attend que l'autre mette fini = 5 */
thread_mutex_lock(&lock);
while (fini != 5)
while (fini != 5) {
printf("le père yield avec le mutex en attendant que le compteur %u soit 5\n", fini);
thread_yield();
}
thread_mutex_unlock(&lock);
/* on baisse progressivement jusque 0 */
for(i=0; i<5; i++) {
printf("le père yield sans le mutex et décrémente le compteur %u\n", fini);
thread_yield();
fini--;
}
@ -75,10 +78,8 @@ int main(void)
/* fini */
err = thread_join(th, NULL);
assert(!err);
gettimeofday(&tv2, NULL);
thread_mutex_destroy(&lock);
us = (tv2.tv_sec-tv1.tv_sec)*1000000+(tv2.tv_usec-tv1.tv_usec);
printf("%lu us\n", us);
printf("terminé OK\n");
return EXIT_SUCCESS;
}

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@ -6,14 +6,15 @@
#include <sys/time.h>
#include "thread.h"
/* test pour verifier que prendre un mutex ne casse pas le join
/* test pour verifier que prendre un mutex ne casse pas le join.
* si ca deadlock, c'est qu'il y a un problème.
* la durée du test n'est pas clairement utilisable pour juger de la qualité de l'implementation.
*
* valgrind doit etre content.
* Le programme doit finir.
*
* support nécessaire:
* - thread_create()
* - retour sans thread_exit()
* - thread_join() dans un mutex
* - thread_mutex_init()
* - thread_mutex_destroy()
@ -55,12 +56,8 @@ int main(void)
{
thread_t th;
int err;
struct timeval tv1, tv2;
unsigned long us;
void *ret;
gettimeofday(&tv1, NULL);
/* on cree le mutex et le thread */
if (thread_mutex_init(&lock) != 0) {
fprintf(stderr, "thread_mutex_init failed\n");
@ -83,12 +80,10 @@ int main(void)
assert(pret == 2);
printf("pere: join réussi\n");
gettimeofday(&tv2, NULL);
err = thread_mutex_unlock(&lock);
assert(!err);
thread_mutex_destroy(&lock);
us = (tv2.tv_sec-tv1.tv_sec)*1000000+(tv2.tv_usec-tv1.tv_usec);
printf("%lu us\n", us);
printf("terminé OK\n");
return EXIT_SUCCESS;
}