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Use *NSYNC for POSIX threads locking APIs

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Condition variables, barriers, and r/w locks now work very well.
This commit is contained in:
Justine Tunney 2022-09-11 11:02:07 -07:00
parent 3de35e196c
commit b5cb71ab84
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GPG key ID: BE714B4575D6E328
197 changed files with 3734 additions and 3817 deletions
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108
libc/thread/nsync_wait.c Normal file
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/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
│vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2016 Google Inc. │
│ │
│ Licensed under the Apache License, Version 2.0 (the "License"); │
│ you may not use this file except in compliance with the License. │
│ You may obtain a copy of the License at │
│ │
│ http://www.apache.org/licenses/LICENSE-2.0 │
│ │
│ Unless required by applicable law or agreed to in writing, software │
│ distributed under the License is distributed on an "AS IS" BASIS, │
│ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. │
│ See the License for the specific language governing permissions and │
│ limitations under the License. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/mem/mem.h"
#include "third_party/nsync/atomic.h"
#include "third_party/nsync/atomic.internal.h"
#include "third_party/nsync/common.internal.h"
#include "third_party/nsync/dll.h"
#include "third_party/nsync/mu_semaphore.h"
#include "third_party/nsync/wait_s.internal.h"
#include "third_party/nsync/waiter.h"
asm(".ident\t\"\\n\\n\
*NSYNC (Apache 2.0)\\n\
Copyright 2016 Google, Inc.\\n\
https://github.com/google/nsync\"");
// clang-format off
int nsync_wait_n (void *mu, void (*lock) (void *), void (*unlock) (void *),
nsync_time abs_deadline,
int count, struct nsync_waitable_s *waitable[]) {
int ready;
IGNORE_RACES_START ();
for (ready = 0; ready != count &&
nsync_time_cmp ((*waitable[ready]->funcs->ready_time) (
waitable[ready]->v, NULL),
nsync_time_zero) > 0;
ready++) {
}
if (ready == count && nsync_time_cmp (abs_deadline, nsync_time_zero) > 0) {
int i;
int unlocked = 0;
int j;
int enqueued = 1;
waiter *w = nsync_waiter_new_ ();
struct nsync_waiter_s nw_set[4];
struct nsync_waiter_s *nw = nw_set;
if (count > (int) (sizeof (nw_set) / sizeof (nw_set[0]))) {
nw = (struct nsync_waiter_s *) malloc (count * sizeof (nw[0]));
}
for (i = 0; i != count && enqueued; i++) {
nw[i].tag = NSYNC_WAITER_TAG;
nw[i].sem = &w->sem;
nsync_dll_init_ (&nw[i].q, &nw[i]);
ATM_STORE (&nw[i].waiting, 0);
nw[i].flags = 0;
enqueued = (*waitable[i]->funcs->enqueue) (waitable[i]->v, &nw[i]);
}
if (i == count) {
nsync_time min_ntime;
if (mu != NULL) {
(*unlock) (mu);
unlocked = 1;
}
do {
min_ntime = abs_deadline;
for (j = 0; j != count; j++) {
nsync_time ntime;
ntime = (*waitable[j]->funcs->ready_time) (
waitable[j]->v, &nw[j]);
if (nsync_time_cmp (ntime, min_ntime) < 0) {
min_ntime = ntime;
}
}
} while (nsync_time_cmp (min_ntime, nsync_time_zero) > 0 &&
nsync_mu_semaphore_p_with_deadline (&w->sem,
min_ntime) == 0);
}
/* An attempt was made above to enqueue waitable[0..i-1].
Dequeue any that are still enqueued, and remember the index
of the first ready (i.e., not still enqueued) object, if any. */
for (j = 0; j != i; j++) {
int was_still_enqueued =
(*waitable[j]->funcs->dequeue) (waitable[j]->v, &nw[j]);
if (!was_still_enqueued && ready == count) {
ready = j;
}
}
if (nw != nw_set) {
free (nw);
}
nsync_waiter_free_ (w);
if (unlocked) {
(*lock) (mu);
}
}
IGNORE_RACES_END ();
return (ready);
}