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feat: use ufd_t instead of lastthread

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Nemo D'ACREMONT 2025-04-18 19:55:02 +02:00
parent da2b87ad05
commit 2df4b8b662
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GPG Key ID: 85F245EC3BB1E022
2 changed files with 21 additions and 77 deletions
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4
Makefile
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@ -97,10 +97,10 @@ ${check_targets}: check_%: ${build_dir}/${tst_dir}/%
${bins_target}: ${build_dir}/%: ${objs} ${build_dir}/%.o
${CC} -o $@ $^ ${CFLAGS} ./lib/libmimalloc ${LDFLAGS}
${build_dir}/${tst_dir}/51-fibonacci: ${build_dir}/src/thread/thread_fibo.o ${build_dir}/${tst_dir}/51-fibonacci.o
${build_dir}/${tst_dir}/51-fibonacci: ${build_dir}/src/thread/thread_fibo.o ${build_dir}/${tst_dir}/51-fibonacci.o ${build_dir}/src/utils/ufd.o
${CC} -o $@ $^ ${CFLAGS} ./lib/libmimalloc ${LDFLAGS}
${build_dir}/${tst_dir}/71-preemption: ${build_dir}/src/thread/thread_preempt.o ${build_dir}/${tst_dir}/71-preemption.o
${build_dir}/${tst_dir}/71-preemption: ${build_dir}/src/thread/thread_preempt.o ${build_dir}/${tst_dir}/71-preemption.o ${build_dir}/src/utils/ufd.o
${CC} -o $@ $^ ${CFLAGS} ./lib/libmimalloc ${LDFLAGS}
${build_dir}/libthread.so: ${objs}

94
src/thread/thread.c
View File

@ -7,6 +7,7 @@
#include <sys/queue.h>
#include <ucontext.h>
#include <valgrind/valgrind.h>
#include "ufd.h"
#include <errno.h>
#define HAS_STATUS(entry, value) ((entry->status) & (value))
@ -18,7 +19,6 @@
#define WAS_ALLOCATED(entry) (HAS_STATUS(entry, ALLOCATED))
#define WAITING (1 << 2)
#define IS_WAITING(entry) (HAS_STATUS(entry, WAITING))
#define GET_LAST_WAITED_THREAD(entry) (entry->last_waited ? entry->last_waited->last_thread : NULL)
#define WAITED (1 << 3)
#define MUTEX_WAITING (1 << 4)
#define MUTEX_LOCKING (1 << 5)
@ -42,7 +42,6 @@ static char stack_for_freeing[STACK_SIZE] = {0};
static int stack_valgrind_id = 0;
static ucontext_t context_for_freeing;
struct last_thread_t;
struct mutex_fifo_entry_t;
struct context_entry_t {
@ -50,7 +49,7 @@ struct context_entry_t {
link; // Use to navigate inside the list
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 ufd_t waited_threads;
struct mutex_fifo_entry_t mutex_fifo_entry;
int valgrind_id;
int status;
@ -68,18 +67,6 @@ static struct scheduler_fifo_t scheduler_fifo = TAILQ_HEAD_INITIALIZER(scheduler
TAILQ_HEAD(ctx_to_free_fifo_t, context_entry_t);
static struct ctx_to_free_fifo_t context_to_freed = TAILQ_HEAD_INITIALIZER(context_to_freed);
// Last thread_t types and fifo
// Used to optimize thread_join
struct last_thread_t {
STAILQ_ENTRY(last_thread_t)
link;
struct context_entry_t * last_thread;
int ref; // number of reference to this struct (for free)
};
STAILQ_HEAD(last_thread_fifo_t, last_thread_t);
struct last_thread_fifo_t last_thread_freed = STAILQ_HEAD_INITIALIZER(last_thread_freed);
int thread_yield(void)
{
//TRACE("thread_yield");
@ -166,7 +153,7 @@ int thread_create(thread_t* newthread, void* (*func)(void*), void* funcarg)
TRACE("ALLOCATED %p", new_entry);
new_entry->status = ALLOCATED;
new_entry->retvalue = NULL;
new_entry->last_waited = NULL;
ufd__init(&new_entry->waited_threads, new_entry);
new_entry->mutex_prio = MUTEX_MAXPRIO;
*newthread = new_entry;
@ -191,11 +178,11 @@ int thread_join(thread_t thread, void** retval)
TRACE("Join thread %p", thread);
struct context_entry_t* entry = thread;
// Check if the target is not already waited by another
if (IS_WAITED(entry)) {
if (IS_WAITED(entry))
return -1;
}
if(GET_LAST_WAITED_THREAD(entry) == running) {
struct context_entry_t* entry_last_waited = ufd__find(&entry->waited_threads)->thread;
if (entry_last_waited == running) {
TRACE("Deadlock detected");
return EDEADLK;
}
@ -203,70 +190,34 @@ int thread_join(thread_t thread, void** retval)
if (!IS_FINISHED(entry)) {
// Use status to be in waiting state
SET_STATUS(running, WAITING);
// Mark the waited thread as waited to not be waited by any other thread.
SET_STATUS(entry, WAITED);
// Use retvalue to share which thread is currently waiting for this thread
entry->retvalue = running;
/** Deadlock **/
// if the running thread is solo (not waited by anyone)
if(!IS_WAITED(running)) {
// if the thread that we want to join is already in a "group" of waiting threads
if (IS_WAITING(entry)) {
// give the last thread waited to the running thread
running->last_waited = entry->last_waited;
}
else { // the thread we want to join is solo
if (STAILQ_EMPTY(&last_thread_freed)) {
running->last_waited = malloc(sizeof(struct last_thread_t));
} else {
running->last_waited = STAILQ_FIRST(&last_thread_freed);
STAILQ_REMOVE_HEAD(&last_thread_freed, link);
}
running->last_waited->ref = 0 ;
entry->last_waited = running->last_waited;
running->last_waited->last_thread = entry;
}
running->last_waited->ref++;
} else { // the running thread is already part of a groupe of waiting threads
if (IS_WAITING(entry)) { // the thread we want to join is part of a groupe of waiting threads
// release the last_waited of this entry
running->last_waited->last_thread = GET_LAST_WAITED_THREAD(entry);
}
else { // the thread we want to join is solo and has no last_waited allocated
running->last_waited->last_thread = entry;
entry->last_waited = running->last_waited;
entry->last_waited->ref ++;
}
}
ufd__join(&running->waited_threads, &entry->waited_threads);
struct context_entry_t* running_last_waited = ufd__find(&running->waited_threads)->thread;
DBG("%p is waiting for %p", running, entry);
DBG("MUTEX WAITING %d", IS_MUTEX_WAITING(GET_LAST_WAITED_THREAD(running)));
DBG("MUTEX WAITING %d %p", IS_MUTEX_WAITING(running_last_waited));
#ifdef FIBO_STRAT
#else
if (!IS_MUTEX_WAITING(GET_LAST_WAITED_THREAD(running))) {
TAILQ_REMOVE(&scheduler_fifo, GET_LAST_WAITED_THREAD(running), link);
TAILQ_INSERT_HEAD(&scheduler_fifo, GET_LAST_WAITED_THREAD(running), link);
if (!IS_MUTEX_WAITING(running_last_waited)) {
TAILQ_REMOVE(&scheduler_fifo, running_last_waited, link);
TAILQ_INSERT_HEAD(&scheduler_fifo, running_last_waited, link);
}
#endif
do {
thread_yield();
} while (!IS_FINISHED(entry));
ufd__delete(&entry->waited_threads);
// Exit from waiting state
UNSET_STATUS(running, WAITING);
if (running->last_waited) {
// Release the last waited thread if no one use it anymore
DBG("Last waited ref : %d", running->last_waited->ref);
if (--running->last_waited->ref == 0) {
STAILQ_INSERT_TAIL(&last_thread_freed, running->last_waited, link);
// free(running->last_waited);
}
running->last_waited = NULL;
}
}
// Save returned value if needed
@ -335,13 +286,6 @@ void clear_context(void)
free(last);
}
struct last_thread_t* last_thread;
while (!STAILQ_EMPTY(&last_thread_freed)) {
last_thread = STAILQ_FIRST(&last_thread_freed);
STAILQ_REMOVE_HEAD(&last_thread_freed, link);
free(last_thread);
}
VALGRIND_STACK_DEREGISTER(stack_valgrind_id);
exit(0);
}
@ -365,7 +309,7 @@ void __attribute__((constructor)) setup_main_thread()
new_entry->valgrind_id = VALGRIND_STACK_REGISTER(
new_entry->context.uc_stack.ss_sp,
new_entry->context.uc_stack.ss_sp + new_entry->context.uc_stack.ss_size);
new_entry->last_waited = NULL;
ufd__init(&new_entry->waited_threads, new_entry);
new_entry->retvalue = NULL;
new_entry->status = 0;
TAILQ_INSERT_TAIL(&context_to_freed, new_entry, link);
@ -377,7 +321,7 @@ void __attribute__((constructor)) setup_main_thread()
main->status = 0;
main->valgrind_id = 0;
main->retvalue = NULL;
main->last_waited = NULL;
ufd__init(&main->waited_threads, main);
running = main;
// Create a context with static stack to clean everything at the end.