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c7c4d063f5
This emulates Win32 manual-reset events using futexes or conditional
variables. Typical ways to use them are with multi-producer,
single-consumer data structures, to test for a complex condition whose
elements come from different threads:
for (;;) {
qemu_event_reset(ev);
... test complex condition ...
if (condition is true) {
break;
}
qemu_event_wait(ev);
}
Or more efficiently (but with some duplication):
... evaluate condition ...
while (!condition) {
qemu_event_reset(ev);
... evaluate condition ...
if (!condition) {
qemu_event_wait(ev);
... evaluate condition ...
}
}
QemuEvent provides a very fast userspace path in the common case when
no other thread is waiting, or the event is not changing state.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
37 lines
551 B
C
37 lines
551 B
C
#ifndef __QEMU_THREAD_POSIX_H
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#define __QEMU_THREAD_POSIX_H 1
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#include "pthread.h"
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#include <semaphore.h>
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struct QemuMutex {
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pthread_mutex_t lock;
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};
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struct QemuCond {
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pthread_cond_t cond;
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};
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struct QemuSemaphore {
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#if defined(__APPLE__) || defined(__NetBSD__)
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pthread_mutex_t lock;
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pthread_cond_t cond;
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unsigned int count;
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#else
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sem_t sem;
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#endif
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};
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struct QemuEvent {
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#ifndef __linux__
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pthread_mutex_t lock;
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pthread_cond_t cond;
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#endif
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unsigned value;
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};
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struct QemuThread {
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pthread_t thread;
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};
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#endif
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