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Introduce pthread_rwlock_try{rd,wr}lock

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This also changes recursive mutexes to favor cpu over scheduler yield.
This commit is contained in:
Justine Tunney 2023-10-31 21:59:05 -07:00
parent a1e1e821cb
commit fadb64a2bf
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GPG key ID: BE714B4575D6E328
13 changed files with 122 additions and 29 deletions
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1
libc/thread/pthread_create.c
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@ -57,6 +57,7 @@
__static_yoink("nsync_mu_lock");
__static_yoink("nsync_mu_unlock");
__static_yoink("nsync_mu_trylock");
__static_yoink("nsync_mu_rlock");
__static_yoink("nsync_mu_runlock");
__static_yoink("_pthread_atfork");

37
libc/thread/pthread_rwlock_tryrdlock.c Normal file
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@ -0,0 +1,37 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/errno.h"
#include "libc/thread/thread.h"
#include "third_party/nsync/mu.h"
/**
* Attempts acquiring read lock on read-write lock.
*
* @return 0 if lock was acquired, otherwise an errno
* @raise EBUSY if lock is currently held in write mode
* @raise EAGAIN if maximum number of read locks are held
* @raise EINVAL if `rwlock` doesn't refer to an initialized r/w lock
*/
errno_t pthread_rwlock_tryrdlock(pthread_rwlock_t *rwlock) {
if (nsync_mu_rtrylock((nsync_mu *)rwlock)) {
return 0;
} else {
return EBUSY;
}
}

37
libc/thread/pthread_rwlock_trywrlock.c Normal file
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@ -0,0 +1,37 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/errno.h"
#include "libc/thread/thread.h"
#include "third_party/nsync/mu.h"
/**
* Attempts acquiring write lock on read-write lock.
*
* @return 0 if lock was acquired, otherwise an errno
* @raise EBUSY if lock is currently held in read or write mode
* @raise EINVAL if `rwlock` doesn't refer to an initialized r/w lock
*/
errno_t pthread_rwlock_trywrlock(pthread_rwlock_t *rwlock) {
if (nsync_mu_trylock((nsync_mu *)rwlock)) {
rwlock->_iswrite = 1;
return 0;
} else {
return EBUSY;
}
}