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kernel/condition_variable: Use cpu_wait in one of the spin-loops.

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The other spin-loop in this file is over a pointer, and cpu_wait
takes only 32-bit values at the moment. I'm not sure about the
semantics of running cpu_wait on only half a 64-bit value, so
leave that loop alone for the moment.
This commit is contained in:
Augustin Cavalier 2024-10-17 14:57:09 -04:00
parent aa49539d5f
commit 46e4cc614f
1 changed files with 3 additions and 3 deletions
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6
src/system/kernel/condition_variable.cpp
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@ -391,17 +391,17 @@ ConditionVariable::_NotifyLocked(bool all, status_t result)
// The entry must be in the process of trying to remove itself from us.
// Clear its variable and wait for it to acknowledge this in fEntriesCount,
// as it is the one responsible for decrementing that.
const int32 oldCount = atomic_get(&fEntriesCount);
const int32 removedCount = atomic_get(&fEntriesCount) - 1;
atomic_pointer_set(&entry->fVariable, (ConditionVariable*)NULL);
// As fEntriesCount is only modified while our lock is held, nothing else
// will modify it while we are spinning, since we hold it at present.
int32 tries = 0;
while (atomic_get(&fEntriesCount) == oldCount) {
while (atomic_get(&fEntriesCount) != removedCount) {
tries++;
if ((tries % 10000) == 0)
dprintf("entries count was not decremented for a long time!\n");
cpu_pause();
cpu_wait(&fEntriesCount, removedCount);
}
} else {
SpinLocker schedulerLocker(thread->scheduler_lock);