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8225628: Remove unused Thread::muxAcquireW function

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Reviewed-by: dcubed, hseigel
This commit is contained in:
Coleen Phillimore 2019-09-20 10:23:40 -04:00
parent b15b322cf3
commit b770e9a6b4
2 changed files with 0 additions and 60 deletions
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59
src/hotspot/share/runtime/thread.cpp
View File

@ -4992,65 +4992,6 @@ void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
}
}
void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
if (w == 0) return;
if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
return;
}
ParkEvent * ReleaseAfter = NULL;
if (ev == NULL) {
ev = ReleaseAfter = ParkEvent::Allocate(NULL);
}
assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
for (;;) {
guarantee(ev->OnList == 0, "invariant");
int its = (os::is_MP() ? 100 : 0) + 1;
// Optional spin phase: spin-then-park strategy
while (--its >= 0) {
w = *Lock;
if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
if (ReleaseAfter != NULL) {
ParkEvent::Release(ReleaseAfter);
}
return;
}
}
ev->reset();
ev->OnList = intptr_t(Lock);
// The following fence() isn't _strictly necessary as the subsequent
// CAS() both serializes execution and ratifies the fetched *Lock value.
OrderAccess::fence();
for (;;) {
w = *Lock;
if ((w & LOCKBIT) == 0) {
if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
ev->OnList = 0;
// We call ::Release while holding the outer lock, thus
// artificially lengthening the critical section.
// Consider deferring the ::Release() until the subsequent unlock(),
// after we've dropped the outer lock.
if (ReleaseAfter != NULL) {
ParkEvent::Release(ReleaseAfter);
}
return;
}
continue; // Interference -- *Lock changed -- Just retry
}
assert(w & LOCKBIT, "invariant");
ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
}
while (ev->OnList != 0) {
ev->park();
}
}
}
// Release() must extract a successor from the list and then wake that thread.
// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based

1
src/hotspot/share/runtime/thread.hpp
View File

@ -802,7 +802,6 @@ protected:
static void SpinAcquire(volatile int * Lock, const char * Name);
static void SpinRelease(volatile int * Lock);
static void muxAcquire(volatile intptr_t * Lock, const char * Name);
static void muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev);
static void muxRelease(volatile intptr_t * Lock);
};