Mercurial > hg > truffle
changeset 1608:2389669474a6
Merge
| author | jrose |
|---|---|
| date | Tue, 15 Jun 2010 15:57:36 -0700 |
| parents | b9bc732be7c0 (diff) 78fc92dfd4ca (current diff) |
| children | 4311f23817fd |
| files | src/share/vm/classfile/classFileParser.cpp src/share/vm/runtime/thread.cpp |
| diffstat | 11 files changed, 293 insertions(+), 92 deletions(-) [+] |
line wrap: on
line diff
--- a/src/share/vm/classfile/classFileParser.cpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/classfile/classFileParser.cpp Tue Jun 15 15:57:36 2010 -0700 @@ -25,10 +25,10 @@ #include "incls/_precompiled.incl" #include "incls/_classFileParser.cpp.incl" -// We generally try to create the oops directly when parsing, rather than allocating -// temporary data structures and copying the bytes twice. A temporary area is only -// needed when parsing utf8 entries in the constant pool and when parsing line number -// tables. +// We generally try to create the oops directly when parsing, rather than +// allocating temporary data structures and copying the bytes twice. A +// temporary area is only needed when parsing utf8 entries in the constant +// pool and when parsing line number tables. // We add assert in debug mode when class format is not checked. @@ -47,6 +47,10 @@ // - also used as the max version when running in jdk6 #define JAVA_6_VERSION 50 +// Used for backward compatibility reasons: +// - to check NameAndType_info signatures more aggressively +#define JAVA_7_VERSION 51 + void ClassFileParser::parse_constant_pool_entries(constantPoolHandle cp, int length, TRAPS) { // Use a local copy of ClassFileStream. It helps the C++ compiler to optimize @@ -461,6 +465,20 @@ verify_legal_class_name(class_name, CHECK_(nullHandle)); break; } + case JVM_CONSTANT_NameAndType: { + if (_need_verify && _major_version >= JAVA_7_VERSION) { + int sig_index = cp->signature_ref_index_at(index); + int name_index = cp->name_ref_index_at(index); + symbolHandle name(THREAD, cp->symbol_at(name_index)); + symbolHandle sig(THREAD, cp->symbol_at(sig_index)); + if (sig->byte_at(0) == JVM_SIGNATURE_FUNC) { + verify_legal_method_signature(name, sig, CHECK_(nullHandle)); + } else { + verify_legal_field_signature(name, sig, CHECK_(nullHandle)); + } + } + break; + } case JVM_CONSTANT_Fieldref: case JVM_CONSTANT_Methodref: case JVM_CONSTANT_InterfaceMethodref: { @@ -473,10 +491,28 @@ symbolHandle signature(THREAD, cp->symbol_at(signature_ref_index)); if (tag == JVM_CONSTANT_Fieldref) { verify_legal_field_name(name, CHECK_(nullHandle)); - verify_legal_field_signature(name, signature, CHECK_(nullHandle)); + if (_need_verify && _major_version >= JAVA_7_VERSION) { + // Signature is verified above, when iterating NameAndType_info. + // Need only to be sure it's the right type. + if (signature->byte_at(0) == JVM_SIGNATURE_FUNC) { + throwIllegalSignature( + "Field", name, signature, CHECK_(nullHandle)); + } + } else { + verify_legal_field_signature(name, signature, CHECK_(nullHandle)); + } } else { verify_legal_method_name(name, CHECK_(nullHandle)); - verify_legal_method_signature(name, signature, CHECK_(nullHandle)); + if (_need_verify && _major_version >= JAVA_7_VERSION) { + // Signature is verified above, when iterating NameAndType_info. + // Need only to be sure it's the right type. + if (signature->byte_at(0) != JVM_SIGNATURE_FUNC) { + throwIllegalSignature( + "Method", name, signature, CHECK_(nullHandle)); + } + } else { + verify_legal_method_signature(name, signature, CHECK_(nullHandle)); + } if (tag == JVM_CONSTANT_Methodref) { // 4509014: If a class method name begins with '<', it must be "<init>". assert(!name.is_null(), "method name in constant pool is null"); @@ -1427,6 +1463,14 @@ return checked_exceptions_start; } +void ClassFileParser::throwIllegalSignature( + const char* type, symbolHandle name, symbolHandle sig, TRAPS) { + ResourceMark rm(THREAD); + Exceptions::fthrow(THREAD_AND_LOCATION, + vmSymbols::java_lang_ClassFormatError(), + "%s \"%s\" in class %s has illegal signature \"%s\"", type, + name->as_C_string(), _class_name->as_C_string(), sig->as_C_string()); +} #define MAX_ARGS_SIZE 255 #define MAX_CODE_SIZE 65535 @@ -4172,14 +4216,7 @@ char* p = skip_over_field_signature(bytes, false, length, CHECK); if (p == NULL || (p - bytes) != (int)length) { - ResourceMark rm(THREAD); - Exceptions::fthrow( - THREAD_AND_LOCATION, - vmSymbolHandles::java_lang_ClassFormatError(), - "Field \"%s\" in class %s has illegal signature \"%s\"", - name->as_C_string(), _class_name->as_C_string(), bytes - ); - return; + throwIllegalSignature("Field", name, signature, CHECK); } } @@ -4230,13 +4267,7 @@ } } // Report error - ResourceMark rm(THREAD); - Exceptions::fthrow( - THREAD_AND_LOCATION, - vmSymbolHandles::java_lang_ClassFormatError(), - "Method \"%s\" in class %s has illegal signature \"%s\"", - name->as_C_string(), _class_name->as_C_string(), p - ); + throwIllegalSignature("Method", name, signature, CHECK_0); return 0; }
--- a/src/share/vm/classfile/classFileParser.hpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/classfile/classFileParser.hpp Tue Jun 15 15:57:36 2010 -0700 @@ -195,6 +195,9 @@ if (!b) { classfile_parse_error(msg, index, name, CHECK); } } + void throwIllegalSignature( + const char* type, symbolHandle name, symbolHandle sig, TRAPS); + bool is_supported_version(u2 major, u2 minor); bool has_illegal_visibility(jint flags);
--- a/src/share/vm/gc_implementation/g1/g1MMUTracker.cpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/gc_implementation/g1/g1MMUTracker.cpp Tue Jun 15 15:57:36 2010 -0700 @@ -81,20 +81,24 @@ remove_expired_entries(end); if (_no_entries == QueueLength) { - // OK, right now when we fill up we bomb out - // there are a few ways of dealing with this "gracefully" + // OK, we've filled up the queue. There are a few ways + // of dealing with this "gracefully" // increase the array size (:-) // remove the oldest entry (this might allow more GC time for - // the time slice than what's allowed) + // the time slice than what's allowed) - this is what we + // currently do // consolidate the two entries with the minimum gap between them // (this might allow less GC time than what's allowed) - guarantee(NOT_PRODUCT(ScavengeALot ||) G1UseFixedWindowMMUTracker, - "array full, currently we can't recover unless +G1UseFixedWindowMMUTracker"); + // In the case where ScavengeALot is true, such overflow is not // uncommon; in such cases, we can, without much loss of precision // or performance (we are GC'ing most of the time anyway!), - // simply overwrite the oldest entry in the tracker: this - // is also the behaviour when G1UseFixedWindowMMUTracker is enabled. + // simply overwrite the oldest entry in the tracker. + + if (G1PolicyVerbose > 1) { + warning("MMU Tracker Queue overflow. Replacing earliest entry."); + } + _head_index = trim_index(_head_index + 1); assert(_head_index == _tail_index, "Because we have a full circular buffer"); _tail_index = trim_index(_tail_index + 1);
--- a/src/share/vm/gc_implementation/g1/g1_globals.hpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/gc_implementation/g1/g1_globals.hpp Tue Jun 15 15:57:36 2010 -0700 @@ -254,9 +254,6 @@ "If non-0 is the size of the G1 survivor space, " \ "otherwise SurvivorRatio is used to determine the size") \ \ - product(bool, G1UseFixedWindowMMUTracker, false, \ - "If the MMU tracker's memory is full, forget the oldest entry") \ - \ product(uintx, G1HeapRegionSize, 0, \ "Size of the G1 regions.") \ \
--- a/src/share/vm/opto/graphKit.cpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/opto/graphKit.cpp Tue Jun 15 15:57:36 2010 -0700 @@ -3487,7 +3487,6 @@ Node* tls = __ thread(); // ThreadLocalStorage - Node* no_ctrl = NULL; Node* no_base = __ top(); float likely = PROB_LIKELY(0.999); float unlikely = PROB_UNLIKELY(0.999); @@ -3511,10 +3510,10 @@ Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset)); // Now some values - - Node* index = __ load(no_ctrl, index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw); - Node* buffer = __ load(no_ctrl, buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw); - + // Use ctrl to avoid hoisting these values past a safepoint, which could + // potentially reset these fields in the JavaThread. + Node* index = __ load(__ ctrl(), index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw); + Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw); // Convert the store obj pointer to an int prior to doing math on it // Must use ctrl to prevent "integerized oop" existing across safepoint
--- a/src/share/vm/runtime/globals.hpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/runtime/globals.hpp Tue Jun 15 15:57:36 2010 -0700 @@ -923,6 +923,10 @@ \ product(intx, AlwaysInflate, 0, "(Unstable) Force inflation") \ \ + product(intx, MonitorBound, 0, "Bound Monitor population") \ + \ + product(bool, MonitorInUseLists, false, "Track Monitors for Deflation") \ + \ product(intx, Atomics, 0, \ "(Unsafe,Unstable) Diagnostic - Controls emission of atomics") \ \
--- a/src/share/vm/runtime/synchronizer.cpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/runtime/synchronizer.cpp Tue Jun 15 15:57:36 2010 -0700 @@ -185,6 +185,8 @@ } ; static SharedGlobals GVars ; +static int MonitorScavengeThreshold = 1000000 ; +static volatile int ForceMonitorScavenge = 0 ; // Scavenge required and pending // Tunables ... @@ -746,8 +748,85 @@ ObjectMonitor * ObjectSynchronizer::gBlockList = NULL ; ObjectMonitor * volatile ObjectSynchronizer::gFreeList = NULL ; static volatile intptr_t ListLock = 0 ; // protects global monitor free-list cache +static volatile int MonitorFreeCount = 0 ; // # on gFreeList +static volatile int MonitorPopulation = 0 ; // # Extant -- in circulation #define CHAINMARKER ((oop)-1) +// Constraining monitor pool growth via MonitorBound ... +// +// The monitor pool is grow-only. We scavenge at STW safepoint-time, but the +// the rate of scavenging is driven primarily by GC. As such, we can find +// an inordinate number of monitors in circulation. +// To avoid that scenario we can artificially induce a STW safepoint +// if the pool appears to be growing past some reasonable bound. +// Generally we favor time in space-time tradeoffs, but as there's no +// natural back-pressure on the # of extant monitors we need to impose some +// type of limit. Beware that if MonitorBound is set to too low a value +// we could just loop. In addition, if MonitorBound is set to a low value +// we'll incur more safepoints, which are harmful to performance. +// See also: GuaranteedSafepointInterval +// +// As noted elsewhere, the correct long-term solution is to deflate at +// monitorexit-time, in which case the number of inflated objects is bounded +// by the number of threads. That policy obviates the need for scavenging at +// STW safepoint time. As an aside, scavenging can be time-consuming when the +// # of extant monitors is large. Unfortunately there's a day-1 assumption baked +// into much HotSpot code that the object::monitor relationship, once established +// or observed, will remain stable except over potential safepoints. +// +// We can use either a blocking synchronous VM operation or an async VM operation. +// -- If we use a blocking VM operation : +// Calls to ScavengeCheck() should be inserted only into 'safe' locations in paths +// that lead to ::inflate() or ::omAlloc(). +// Even though the safepoint will not directly induce GC, a GC might +// piggyback on the safepoint operation, so the caller should hold no naked oops. +// Furthermore, monitor::object relationships are NOT necessarily stable over this call +// unless the caller has made provisions to "pin" the object to the monitor, say +// by incrementing the monitor's _count field. +// -- If we use a non-blocking asynchronous VM operation : +// the constraints above don't apply. The safepoint will fire in the future +// at a more convenient time. On the other hand the latency between posting and +// running the safepoint introduces or admits "slop" or laxity during which the +// monitor population can climb further above the threshold. The monitor population, +// however, tends to converge asymptotically over time to a count that's slightly +// above the target value specified by MonitorBound. That is, we avoid unbounded +// growth, albeit with some imprecision. +// +// The current implementation uses asynchronous VM operations. +// +// Ideally we'd check if (MonitorPopulation > MonitorBound) in omAlloc() +// immediately before trying to grow the global list via allocation. +// If the predicate was true then we'd induce a synchronous safepoint, wait +// for the safepoint to complete, and then again to allocate from the global +// free list. This approach is much simpler and precise, admitting no "slop". +// Unfortunately we can't safely safepoint in the midst of omAlloc(), so +// instead we use asynchronous safepoints. + +static void InduceScavenge (Thread * Self, const char * Whence) { + // Induce STW safepoint to trim monitors + // Ultimately, this results in a call to deflate_idle_monitors() in the near future. + // More precisely, trigger an asynchronous STW safepoint as the number + // of active monitors passes the specified threshold. + // TODO: assert thread state is reasonable + + if (ForceMonitorScavenge == 0 && Atomic::xchg (1, &ForceMonitorScavenge) == 0) { + if (Knob_Verbose) { + ::printf ("Monitor scavenge - Induced STW @%s (%d)\n", Whence, ForceMonitorScavenge) ; + ::fflush(stdout) ; + } + // Induce a 'null' safepoint to scavenge monitors + // Must VM_Operation instance be heap allocated as the op will be enqueue and posted + // to the VMthread and have a lifespan longer than that of this activation record. + // The VMThread will delete the op when completed. + VMThread::execute (new VM_ForceAsyncSafepoint()) ; + + if (Knob_Verbose) { + ::printf ("Monitor scavenge - STW posted @%s (%d)\n", Whence, ForceMonitorScavenge) ; + ::fflush(stdout) ; + } + } +} + ObjectMonitor * ATTR ObjectSynchronizer::omAlloc (Thread * Self) { // A large MAXPRIVATE value reduces both list lock contention // and list coherency traffic, but also tends to increase the @@ -770,6 +849,11 @@ Self->omFreeCount -- ; // CONSIDER: set m->FreeNext = BAD -- diagnostic hygiene guarantee (m->object() == NULL, "invariant") ; + if (MonitorInUseLists) { + m->FreeNext = Self->omInUseList; + Self->omInUseList = m; + Self->omInUseCount ++; + } return m ; } @@ -784,6 +868,7 @@ // on various locks. Thread::muxAcquire (&ListLock, "omAlloc") ; for (int i = Self->omFreeProvision; --i >= 0 && gFreeList != NULL; ) { + MonitorFreeCount --; ObjectMonitor * take = gFreeList ; gFreeList = take->FreeNext ; guarantee (take->object() == NULL, "invariant") ; @@ -796,6 +881,15 @@ if (Self->omFreeProvision > MAXPRIVATE ) Self->omFreeProvision = MAXPRIVATE ; TEVENT (omFirst - reprovision) ; continue ; + + const int mx = MonitorBound ; + if (mx > 0 && (MonitorPopulation-MonitorFreeCount) > mx) { + // We can't safely induce a STW safepoint from omAlloc() as our thread + // state may not be appropriate for such activities and callers may hold + // naked oops, so instead we defer the action. + InduceScavenge (Self, "omAlloc") ; + } + continue; } // 3: allocate a block of new ObjectMonitors @@ -836,6 +930,8 @@ // Acquire the ListLock to manipulate BlockList and FreeList. // An Oyama-Taura-Yonezawa scheme might be more efficient. Thread::muxAcquire (&ListLock, "omAlloc [2]") ; + MonitorPopulation += _BLOCKSIZE-1; + MonitorFreeCount += _BLOCKSIZE-1; // Add the new block to the list of extant blocks (gBlockList). // The very first objectMonitor in a block is reserved and dedicated. @@ -894,7 +990,9 @@ if (List == NULL) return ; ObjectMonitor * Tail = NULL ; ObjectMonitor * s ; + int Tally = 0; for (s = List ; s != NULL ; s = s->FreeNext) { + Tally ++ ; Tail = s ; guarantee (s->object() == NULL, "invariant") ; guarantee (!s->is_busy(), "invariant") ; @@ -906,6 +1004,7 @@ Thread::muxAcquire (&ListLock, "omFlush") ; Tail->FreeNext = gFreeList ; gFreeList = List ; + MonitorFreeCount += Tally; Thread::muxRelease (&ListLock) ; TEVENT (omFlush) ; } @@ -1747,16 +1846,15 @@ // Having a large number of monitors in-circulation negatively // impacts the performance of some applications (e.g., PointBase). // Broadly, we want to minimize the # of monitors in circulation. -// Alternately, we could partition the active monitors into sub-lists -// of those that need scanning and those that do not. -// Specifically, we would add a new sub-list of objectmonitors -// that are in-circulation and potentially active. deflate_idle_monitors() -// would scan only that list. Other monitors could reside on a quiescent -// list. Such sequestered monitors wouldn't need to be scanned by -// deflate_idle_monitors(). omAlloc() would first check the global free list, -// then the quiescent list, and, failing those, would allocate a new block. -// Deflate_idle_monitors() would scavenge and move monitors to the -// quiescent list. +// +// We have added a flag, MonitorInUseLists, which creates a list +// of active monitors for each thread. deflate_idle_monitors() +// only scans the per-thread inuse lists. omAlloc() puts all +// assigned monitors on the per-thread list. deflate_idle_monitors() +// returns the non-busy monitors to the global free list. +// An alternative could have used a single global inuse list. The +// downside would have been the additional cost of acquiring the global list lock +// for every omAlloc(). // // Perversely, the heap size -- and thus the STW safepoint rate -- // typically drives the scavenge rate. Large heaps can mean infrequent GC, @@ -1769,18 +1867,100 @@ // An even better solution would be to deflate on-the-fly, aggressively, // at monitorexit-time as is done in EVM's metalock or Relaxed Locks. + +// Deflate a single monitor if not in use +// Return true if deflated, false if in use +bool ObjectSynchronizer::deflate_monitor(ObjectMonitor* mid, oop obj, + ObjectMonitor** FreeHeadp, ObjectMonitor** FreeTailp) { + bool deflated; + // Normal case ... The monitor is associated with obj. + guarantee (obj->mark() == markOopDesc::encode(mid), "invariant") ; + guarantee (mid == obj->mark()->monitor(), "invariant"); + guarantee (mid->header()->is_neutral(), "invariant"); + + if (mid->is_busy()) { + if (ClearResponsibleAtSTW) mid->_Responsible = NULL ; + deflated = false; + } else { + // Deflate the monitor if it is no longer being used + // It's idle - scavenge and return to the global free list + // plain old deflation ... + TEVENT (deflate_idle_monitors - scavenge1) ; + if (TraceMonitorInflation) { + if (obj->is_instance()) { + ResourceMark rm; + tty->print_cr("Deflating object " INTPTR_FORMAT " , mark " INTPTR_FORMAT " , type %s", + (intptr_t) obj, (intptr_t) obj->mark(), Klass::cast(obj->klass())->external_name()); + } + } + + // Restore the header back to obj + obj->release_set_mark(mid->header()); + mid->clear(); + + assert (mid->object() == NULL, "invariant") ; + + // Move the object to the working free list defined by FreeHead,FreeTail. + if (*FreeHeadp == NULL) *FreeHeadp = mid; + if (*FreeTailp != NULL) { + ObjectMonitor * prevtail = *FreeTailp; + prevtail->FreeNext = mid; + } + *FreeTailp = mid; + deflated = true; + } + return deflated; +} + void ObjectSynchronizer::deflate_idle_monitors() { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); int nInuse = 0 ; // currently associated with objects int nInCirculation = 0 ; // extant int nScavenged = 0 ; // reclaimed + bool deflated = false; ObjectMonitor * FreeHead = NULL ; // Local SLL of scavenged monitors ObjectMonitor * FreeTail = NULL ; + TEVENT (deflate_idle_monitors) ; + // Prevent omFlush from changing mids in Thread dtor's during deflation + // And in case the vm thread is acquiring a lock during a safepoint + // See e.g. 6320749 + Thread::muxAcquire (&ListLock, "scavenge - return") ; + + if (MonitorInUseLists) { + ObjectMonitor* mid; + ObjectMonitor* next; + ObjectMonitor* curmidinuse; + for (JavaThread* cur = Threads::first(); cur != NULL; cur = cur->next()) { + curmidinuse = NULL; + for (mid = cur->omInUseList; mid != NULL; ) { + oop obj = (oop) mid->object(); + deflated = false; + if (obj != NULL) { + deflated = deflate_monitor(mid, obj, &FreeHead, &FreeTail); + } + if (deflated) { + // extract from per-thread in-use-list + if (mid == cur->omInUseList) { + cur->omInUseList = mid->FreeNext; + } else if (curmidinuse != NULL) { + curmidinuse->FreeNext = mid->FreeNext; // maintain the current thread inuselist + } + next = mid->FreeNext; + mid->FreeNext = NULL; // This mid is current tail in the FreeHead list + mid = next; + cur->omInUseCount--; + nScavenged ++ ; + } else { + curmidinuse = mid; + mid = mid->FreeNext; + nInuse ++; + } + } + } + } else for (ObjectMonitor* block = gBlockList; block != NULL; block = next(block)) { // Iterate over all extant monitors - Scavenge all idle monitors. - TEVENT (deflate_idle_monitors) ; - for (ObjectMonitor* block = gBlockList; block != NULL; block = next(block)) { assert(block->object() == CHAINMARKER, "must be a block header"); nInCirculation += _BLOCKSIZE ; for (int i = 1 ; i < _BLOCKSIZE; i++) { @@ -1795,61 +1975,39 @@ guarantee (!mid->is_busy(), "invariant") ; continue ; } - - // Normal case ... The monitor is associated with obj. - guarantee (obj->mark() == markOopDesc::encode(mid), "invariant") ; - guarantee (mid == obj->mark()->monitor(), "invariant"); - guarantee (mid->header()->is_neutral(), "invariant"); - - if (mid->is_busy()) { - if (ClearResponsibleAtSTW) mid->_Responsible = NULL ; - nInuse ++ ; + deflated = deflate_monitor(mid, obj, &FreeHead, &FreeTail); + + if (deflated) { + mid->FreeNext = NULL ; + nScavenged ++ ; } else { - // Deflate the monitor if it is no longer being used - // It's idle - scavenge and return to the global free list - // plain old deflation ... - TEVENT (deflate_idle_monitors - scavenge1) ; - if (TraceMonitorInflation) { - if (obj->is_instance()) { - ResourceMark rm; - tty->print_cr("Deflating object " INTPTR_FORMAT " , mark " INTPTR_FORMAT " , type %s", - (intptr_t) obj, (intptr_t) obj->mark(), Klass::cast(obj->klass())->external_name()); - } - } - - // Restore the header back to obj - obj->release_set_mark(mid->header()); - mid->clear(); - - assert (mid->object() == NULL, "invariant") ; - - // Move the object to the working free list defined by FreeHead,FreeTail. - mid->FreeNext = NULL ; - if (FreeHead == NULL) FreeHead = mid ; - if (FreeTail != NULL) FreeTail->FreeNext = mid ; - FreeTail = mid ; - nScavenged ++ ; + nInuse ++; } } } + MonitorFreeCount += nScavenged; + + // Consider: audit gFreeList to ensure that MonitorFreeCount and list agree. + + if (Knob_Verbose) { + ::printf ("Deflate: InCirc=%d InUse=%d Scavenged=%d ForceMonitorScavenge=%d : pop=%d free=%d\n", + nInCirculation, nInuse, nScavenged, ForceMonitorScavenge, + MonitorPopulation, MonitorFreeCount) ; + ::fflush(stdout) ; + } + + ForceMonitorScavenge = 0; // Reset + // Move the scavenged monitors back to the global free list. - // In theory we don't need the freelist lock as we're at a STW safepoint. - // omAlloc() and omFree() can only be called while a thread is _not in safepoint state. - // But it's remotely possible that omFlush() or release_monitors_owned_by_thread() - // might be called while not at a global STW safepoint. In the interest of - // safety we protect the following access with ListLock. - // An even more conservative and prudent approach would be to guard - // the main loop in scavenge_idle_monitors() with ListLock. if (FreeHead != NULL) { guarantee (FreeTail != NULL && nScavenged > 0, "invariant") ; assert (FreeTail->FreeNext == NULL, "invariant") ; // constant-time list splice - prepend scavenged segment to gFreeList - Thread::muxAcquire (&ListLock, "scavenge - return") ; FreeTail->FreeNext = gFreeList ; gFreeList = FreeHead ; - Thread::muxRelease (&ListLock) ; } + Thread::muxRelease (&ListLock) ; if (_sync_Deflations != NULL) _sync_Deflations->inc(nScavenged) ; if (_sync_MonExtant != NULL) _sync_MonExtant ->set_value(nInCirculation);
--- a/src/share/vm/runtime/synchronizer.hpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/runtime/synchronizer.hpp Tue Jun 15 15:57:36 2010 -0700 @@ -150,6 +150,8 @@ // Basically we deflate all monitors that are not busy. // An adaptive profile-based deflation policy could be used if needed static void deflate_idle_monitors(); + static bool deflate_monitor(ObjectMonitor* mid, oop obj, ObjectMonitor** FreeHeadp, + ObjectMonitor** FreeTailp); static void oops_do(OopClosure* f); // debugging
--- a/src/share/vm/runtime/thread.cpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/runtime/thread.cpp Tue Jun 15 15:57:36 2010 -0700 @@ -139,6 +139,8 @@ omFreeList = NULL ; omFreeCount = 0 ; omFreeProvision = 32 ; + omInUseList = NULL ; + omInUseCount = 0 ; _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); _suspend_flags = 0;
--- a/src/share/vm/runtime/thread.hpp Tue Jun 15 12:06:52 2010 -0700 +++ b/src/share/vm/runtime/thread.hpp Tue Jun 15 15:57:36 2010 -0700 @@ -225,6 +225,8 @@ ObjectMonitor * omFreeList ; int omFreeCount ; // length of omFreeList int omFreeProvision ; // reload chunk size + ObjectMonitor * omInUseList; // SLL to track monitors in circulation + int omInUseCount; // length of omInUseList public: enum { @@ -493,7 +495,6 @@ static ByteSize stack_base_offset() { return byte_offset_of(Thread, _stack_base ); } static ByteSize stack_size_offset() { return byte_offset_of(Thread, _stack_size ); } - static ByteSize omFreeList_offset() { return byte_offset_of(Thread, omFreeList); } #define TLAB_FIELD_OFFSET(name) \ static ByteSize tlab_##name##_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }