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8073165: Contended Locking fast exit bucket
JEP-143/JDK-8073165 Contended Locking fast exit bucket Co-authored-by: Dave Dice <dave.dice@oracle.com> Co-authored-by: Karen Kinnear <karen.kinnear@oracle.com> Reviewed-by: dholmes, acorn, dice, dcubed
This commit is contained in:
Daniel D. Daugherty
parent
d30de5ab31
commit
884f0d320f
14 changed files with 326 additions and 215 deletions
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@ -3019,44 +3019,107 @@ void MacroAssembler::compiler_unlock_object(Register Roop, Register Rmark,
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// past the store that releases the lock. But TSO is a strong memory model
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// and that particular flavor of barrier is a noop, so we can safely elide it.
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// Note that we use 1-0 locking by default for the inflated case. We
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// close the resultant (and rare) race by having contented threads in
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// close the resultant (and rare) race by having contended threads in
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// monitorenter periodically poll _owner.
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ld_ptr(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner), Rscratch);
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ld_ptr(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(recursions), Rbox);
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xor3(Rscratch, G2_thread, Rscratch);
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orcc(Rbox, Rscratch, Rbox);
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brx(Assembler::notZero, false, Assembler::pn, done);
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delayed()->
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ld_ptr(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(EntryList), Rscratch);
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ld_ptr(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(cxq), Rbox);
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orcc(Rbox, Rscratch, G0);
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if (EmitSync & 65536) {
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Label LSucc ;
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brx(Assembler::notZero, false, Assembler::pn, LSucc);
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delayed()->nop();
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ba(done);
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delayed()->st_ptr(G0, Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner));
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bind(LSucc);
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st_ptr(G0, Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner));
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if (os::is_MP()) { membar (StoreLoad); }
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ld_ptr(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(succ), Rscratch);
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andcc(Rscratch, Rscratch, G0);
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brx(Assembler::notZero, false, Assembler::pt, done);
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delayed()->andcc(G0, G0, G0);
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add(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner), Rmark);
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mov(G2_thread, Rscratch);
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cas_ptr(Rmark, G0, Rscratch);
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// invert icc.zf and goto done
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br_notnull(Rscratch, false, Assembler::pt, done);
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delayed()->cmp(G0, G0);
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ba(done);
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delayed()->cmp(G0, 1);
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if (EmitSync & 1024) {
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// Emit code to check that _owner == Self
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// We could fold the _owner test into subsequent code more efficiently
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// than using a stand-alone check, but since _owner checking is off by
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// default we don't bother. We also might consider predicating the
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// _owner==Self check on Xcheck:jni or running on a debug build.
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)), Rscratch);
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orcc(Rscratch, G0, G0);
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brx(Assembler::notZero, false, Assembler::pn, done);
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delayed()->nop();
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}
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if (EmitSync & 512) {
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// classic lock release code absent 1-0 locking
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// m->Owner = null;
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// membar #storeload
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// if (m->cxq|m->EntryList) == null goto Success
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// if (m->succ != null) goto Success
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// if CAS (&m->Owner,0,Self) != 0 goto Success
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// goto SlowPath
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(recursions)), Rbox);
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orcc(Rbox, G0, G0);
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brx(Assembler::notZero, false, Assembler::pn, done);
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delayed()->nop();
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st_ptr(G0, Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
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if (os::is_MP()) { membar(StoreLoad); }
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(EntryList)), Rscratch);
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(cxq)), Rbox);
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orcc(Rbox, Rscratch, G0);
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brx(Assembler::zero, false, Assembler::pt, done);
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delayed()->
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(succ)), Rscratch);
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andcc(Rscratch, Rscratch, G0);
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brx(Assembler::notZero, false, Assembler::pt, done);
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delayed()->andcc(G0, G0, G0);
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add(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner), Rmark);
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mov(G2_thread, Rscratch);
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cas_ptr(Rmark, G0, Rscratch);
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cmp(Rscratch, G0);
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// invert icc.zf and goto done
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brx(Assembler::notZero, false, Assembler::pt, done);
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delayed()->cmp(G0, G0);
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br(Assembler::always, false, Assembler::pt, done);
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delayed()->cmp(G0, 1);
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} else {
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brx(Assembler::notZero, false, Assembler::pn, done);
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delayed()->nop();
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ba(done);
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delayed()->st_ptr(G0, Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner));
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// 1-0 form : avoids CAS and MEMBAR in the common case
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// Do not bother to ratify that m->Owner == Self.
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(recursions)), Rbox);
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orcc(Rbox, G0, G0);
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brx(Assembler::notZero, false, Assembler::pn, done);
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delayed()->
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(EntryList)), Rscratch);
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(cxq)), Rbox);
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orcc(Rbox, Rscratch, G0);
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if (EmitSync & 16384) {
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// As an optional optimization, if (EntryList|cxq) != null and _succ is null then
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// we should transfer control directly to the slow-path.
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// This test makes the reacquire operation below very infrequent.
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// The logic is equivalent to :
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// if (cxq|EntryList) == null : Owner=null; goto Success
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// if succ == null : goto SlowPath
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// Owner=null; membar #storeload
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// if succ != null : goto Success
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// if CAS(&Owner,null,Self) != null goto Success
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// goto SlowPath
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brx(Assembler::zero, true, Assembler::pt, done);
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delayed()->
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st_ptr(G0, Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(succ)), Rscratch);
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andcc(Rscratch, Rscratch, G0) ;
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brx(Assembler::zero, false, Assembler::pt, done);
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delayed()->orcc(G0, 1, G0);
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st_ptr(G0, Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
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} else {
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brx(Assembler::zero, false, Assembler::pt, done);
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delayed()->
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st_ptr(G0, Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
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}
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if (os::is_MP()) { membar(StoreLoad); }
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// Check that _succ is (or remains) non-zero
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ld_ptr(Address(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(succ)), Rscratch);
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andcc(Rscratch, Rscratch, G0);
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brx(Assembler::notZero, false, Assembler::pt, done);
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delayed()->andcc(G0, G0, G0);
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add(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner), Rmark);
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mov(G2_thread, Rscratch);
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cas_ptr(Rmark, G0, Rscratch);
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cmp(Rscratch, G0);
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// invert icc.zf and goto done
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// A slightly better v8+/v9 idiom would be the following:
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// movrnz Rscratch,1,Rscratch
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// ba done
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// xorcc Rscratch,1,G0
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// In v8+ mode the idiom would be valid IFF Rscratch was a G or O register
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brx(Assembler::notZero, false, Assembler::pt, done);
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delayed()->cmp(G0, G0);
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br(Assembler::always, false, Assembler::pt, done);
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delayed()->cmp(G0, 1);
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}
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bind (LStacked);
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