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src/hotspot/share/runtime/objectMonitor.hpp
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rev 56044 : imported patch 8230184.patch
rev 56046 : v2.00 -> v2.05 (CR5/v2.05/8-for-jdk13) patches combined into one; merge with 8229212.patch; merge with jdk-14+11; merge with 8230184.patch.
rev 56048 : Add OM_CACHE_LINE_SIZE so that ObjectMonitor cache line sizes can be experimented with independently of DEFAULT_CACHE_LINE_SIZE; for SPARC and X64 configs that use 128 for DEFAULT_CACHE_LINE_SIZE, we are experimenting with 64; move _previous_owner_tid and _allocation_state fields to share the cache line with ObjectMonitor::_header; put ObjectMonitor::_ref_count on its own cache line after _owner; add 'int* count_p' parameter to deflate_monitor_list() and deflate_monitor_list_using_JT() and push counter updates down to where the ObjectMonitors are actually removed from the in-use lists; monitors_iterate() async deflation check should use negative ref_count; add 'JavaThread* target' param to deflate_per_thread_idle_monitors_using_JT() add deflate_common_idle_monitors_using_JT() to make it clear which JavaThread* is the target of the work and which is the calling JavaThread* (self); g_free_list, g_om_in_use_list and g_om_in_use_count are now static to synchronizer.cpp (reduce scope); add more diagnostic info to some assert()'s; minor code cleanups and code motion; save_om_ptr() should detect a race with a deflating thread that is bailing out and cause a retry when the ref_count field is not positive; merge with jdk-14+11; add special GC support for TestHumongousClassLoader.java; merge with 8230184.patch.
rev 56049 : Merge the remainder of the lock-free monitor list changes from v2.06 with v2.06a and v2.06b after running the changes through the edit scripts; merge pieces from dcubed.monitor_deflate_conc.v2.06d in dcubed.monitor_deflate_conc.v2.06[ac]; merge pieces from dcubed.monitor_deflate_conc.v2.06e into dcubed.monitor_deflate_conc.v2.06c; merge with jdk-14+11; test work around for test/jdk/tools/jlink/multireleasejar/JLinkMultiReleaseJarTest.java should not been needed anymore.
@@ -124,10 +124,16 @@
//
// - The _recursions field should be of type int, or int32_t but not
// intptr_t. There's no reason to use a 64-bit type for this field
// in a 64-bit JVM.
+#ifndef OM_CACHE_LINE_SIZE
+// Use DEFAULT_CACHE_LINE_SIZE if not already specified for
+// the current build platform.
+#define OM_CACHE_LINE_SIZE DEFAULT_CACHE_LINE_SIZE
+#endif
+
class ObjectMonitor {
public:
enum {
OM_OK, // no error
OM_SYSTEM_ERROR, // operating system error
@@ -145,28 +151,43 @@
// The sync code expects the header field to be at offset zero (0).
// Enforced by the assert() in header_addr().
volatile markWord _header; // displaced object header word - mark
void* volatile _object; // backward object pointer - strong root
- public:
- ObjectMonitor* _next_om; // Next ObjectMonitor* linkage
- private:
+ typedef enum {
+ Free = 0, // Free must be 0 for monitor to be free after memset(..,0,..).
+ New,
+ Old
+ } AllocationState;
+ AllocationState _allocation_state;
// Separate _header and _owner on different cache lines since both can
- // have busy multi-threaded access. _header and _object are set at
- // initial inflation and _object doesn't change until deflation so
- // _object is a good choice to share the cache line with _header.
- // _next_om shares _header's cache line for pre-monitor list historical
- // reasons. _next_om only changes if the next ObjectMonitor is deflated.
- DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE,
- sizeof(volatile markWord) + sizeof(void* volatile) +
- sizeof(ObjectMonitor *));
+ // have busy multi-threaded access. _header, _object and _allocation_state
+ // are set at initial inflation. _object and _allocation_state don't
+ // change until deflation so _object and _allocation_state are good
+ // choices to share the cache line with _header.
+ DEFINE_PAD_MINUS_SIZE(0, OM_CACHE_LINE_SIZE, sizeof(volatile markWord) +
+ sizeof(void* volatile) + sizeof(AllocationState));
// Used by async deflation as a marker in the _owner field:
#define DEFLATER_MARKER reinterpret_cast<void*>(-1)
protected: // protected for JvmtiRawMonitor
void* volatile _owner; // pointer to owning thread OR BasicLock
private:
volatile jlong _previous_owner_tid; // thread id of the previous owner of the monitor
+ // Separate _owner and _ref_count on different cache lines since both
+ // can have busy multi-threaded access. _previous_owner_tid is only
+ // changed by ObjectMonitor::exit() so it is a good choice to share the
+ // cache line with _owner.
+ DEFINE_PAD_MINUS_SIZE(1, OM_CACHE_LINE_SIZE, sizeof(void* volatile) +
+ sizeof(volatile jlong));
+ volatile jint _ref_count; // ref count for ObjectMonitor* and used by the async deflation
+ // protocol. See ObjectSynchronizer::deflate_monitor_using_JT().
+ private:
+ // Separate _ref_count and _next_om on different cache lines since
+ // both can have busy multi-threaded access.
+ DEFINE_PAD_MINUS_SIZE(2, OM_CACHE_LINE_SIZE, sizeof(volatile jint));
+ public: // for static synchronizer.cpp access:
+ ObjectMonitor* volatile _next_om; // Next ObjectMonitor* linkage
protected: // protected for JvmtiRawMonitor
volatile intptr_t _recursions; // recursion count, 0 for first entry
ObjectWaiter* volatile _EntryList; // Threads blocked on entry or reentry.
// The list is actually composed of WaitNodes,
// acting as proxies for Threads.
@@ -185,20 +206,13 @@
protected:
ObjectWaiter* volatile _WaitSet; // LL of threads wait()ing on the monitor
volatile jint _waiters; // number of waiting threads
private:
volatile int _WaitSetLock; // protects Wait Queue - simple spinlock
- volatile jint _ref_count; // ref count for ObjectMonitor* and used by the async deflation
- // protocol. See ObjectSynchronizer::deflate_monitor_using_JT().
- typedef enum {
- Free = 0, // Free must be 0 for monitor to be free after memset(..,0,..).
- New,
- Old
- } AllocationState;
- AllocationState _allocation_state;
public:
+ volatile int visit_marker;
static void Initialize();
// Only perform a PerfData operation if the PerfData object has been
// allocated and if the PerfDataManager has not freed the PerfData
// objects which can happen at normal VM shutdown.
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