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0b3c81dd4e
This change makes fork() go nearly as fast as sys_fork() on UNIX. As for Windows this change shaves about 4-5ms off fork() + wait() latency. This is accomplished by using WriteProcessMemory() from the parent process to setup the address space of a suspended process; it is better than a pipe
39 lines
2.4 KiB
C
39 lines
2.4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2024 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/intrin/atomic.h"
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#include "libc/str/str.h"
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#include "libc/thread/lock.h"
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#include "libc/thread/posixthread.internal.h"
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#include "libc/thread/thread.h"
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/**
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* Unlocks mutex from child process after fork.
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*/
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int _pthread_mutex_wipe_np(pthread_mutex_t *mutex) {
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atomic_init(&mutex->_word, MUTEX_UNLOCK(atomic_load_explicit(
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&mutex->_word, memory_order_relaxed)));
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atomic_init(&mutex->_futex, 0);
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mutex->_pid = 0;
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mutex->_nsync[0] = 0;
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atomic_signal_fence(memory_order_relaxed); // avoid xmm
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mutex->_nsync[1] = 0;
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return 0;
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}
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__weak_reference(_pthread_mutex_wipe_np, pthread_mutex_wipe_np);
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