< prev index next >
src/hotspot/share/runtime/synchronizer.hpp
Print this page
rev 56635 : 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; merge with 8230876.patch; merge with jdk-14+15; merge with jdk-14+18.
rev 56637 : 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; merge with jdk-14+14; merge with jdk-14+18.
rev 56638 : 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; merge with jdk-14+18.
rev 56639 : loosen a couple more counter checks due to races observed in testing; simplify om_release() extraction of mid since list head or cur_mid_in_use is marked; simplify deflate_monitor_list() extraction of mid since there are no parallel deleters due to the safepoint; simplify deflate_monitor_list_using_JT() extraction of mid since list head or cur_mid_in_use is marked; prepend_block_to_lists() - simplify based on David H's comments; does not need load_acquire() or release_store() because of the cmpxchg(); prepend_to_common() - simplify to use mark_next_loop() for m and use mark_list_head() and release_store() for the non-empty list case; add more debugging for "Non-balanced monitor enter/exit" failure mode; fix race in inflate() in the "CASE: neutral" code path; install_displaced_markword_in_object() does not need to clear the header field since that is handled when the ObjectMonitor is moved from the global free list; LSuccess should clear boxReg to set ICC.ZF=1 to avoid depending on existing boxReg contents; update fast_unlock() to detect when object no longer refers to the same ObjectMonitor and take fast path exit instead; clarify fast_lock() code where we detect when object no longer refers to the same ObjectMonitor; add/update comments for movptr() calls where we move a literal into an Address; remove set_owner(); refactor setting of owner field into set_owner_from(2 versions), set_owner_from_BasicLock(), and try_set_owner_from(); the new functions include monitorinflation+owner logging; extract debug code from v2.06 and v2.07 and move to v2.07.debug; change 'jccb' -> 'jcc' and 'jmpb' -> 'jmp' as needed; checkpoint initial version of MacroAssembler::inc_om_ref_count(); update LP64 MacroAssembler::fast_lock() and fast_unlock() to use inc_om_ref_count(); fast_lock() return flag setting logic can use 'testptr(tmpReg, tmpReg)' instead of 'cmpptr(tmpReg, 0)' since that's more efficient; fast_unlock() LSuccess return flag setting logic can use 'testl (boxReg, 0)' instead of 'xorptr(boxReg, boxReg)' since that's more efficient; cleanup "fast-path" vs "fast path" and "slow-path" vs "slow path"; update MacroAssembler::rtm_inflated_locking() to use inc_om_ref_count(); update MacroAssembler::fast_lock() to preserve the flags before decrementing ref_count and restore the flags afterwards; this is more clean than depending on the contents of rax/tmpReg; coleenp CR - refactor async monitor deflation work from ServiceThread::service_thread_entry() to ObjectSynchronizer::deflate_idle_monitors_using_JT(); rehn,eosterlund CR - add support for HandshakeAfterDeflateIdleMonitors for platforms that don't have ObjectMonitor ref_count support implemented in C2 fast_lock() and fast_unlock().
@@ -30,19 +30,26 @@
#include "runtime/basicLock.hpp"
#include "runtime/handles.hpp"
#include "runtime/perfData.hpp"
class ObjectMonitor;
+class ObjectMonitorHandle;
class ThreadsList;
-typedef PaddedEnd<ObjectMonitor, DEFAULT_CACHE_LINE_SIZE> PaddedObjectMonitor;
+#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
+
+typedef PaddedEnd<ObjectMonitor, OM_CACHE_LINE_SIZE> PaddedObjectMonitor;
struct DeflateMonitorCounters {
- int n_in_use; // currently associated with objects
- int n_in_circulation; // extant
- int n_scavenged; // reclaimed (global and per-thread)
- int per_thread_scavenged; // per-thread scavenge total
+ volatile int n_in_use; // currently associated with objects
+ volatile int n_in_circulation; // extant
+ volatile int n_scavenged; // reclaimed (global and per-thread)
+ volatile int per_thread_scavenged; // per-thread scavenge total
double per_thread_times; // per-thread scavenge times
};
class ObjectSynchronizer : AllStatic {
friend class VMStructs;
@@ -94,19 +101,20 @@
// with original recursion count
static intptr_t complete_exit(Handle obj, TRAPS);
static void reenter (Handle obj, intptr_t recursion, TRAPS);
// thread-specific and global ObjectMonitor free list accessors
- static ObjectMonitor* om_alloc(Thread* self);
+ static ObjectMonitor* om_alloc(Thread* self, const InflateCause cause);
static void om_release(Thread* self, ObjectMonitor* m,
bool FromPerThreadAlloc);
static void om_flush(Thread* self);
// Inflate light weight monitor to heavy weight monitor
- static ObjectMonitor* inflate(Thread* self, oop obj, const InflateCause cause);
+ static void inflate(ObjectMonitorHandle* omh_p, Thread* self, oop obj,
+ const InflateCause cause);
// This version is only for internal use
- static void inflate_helper(oop obj);
+ static void inflate_helper(ObjectMonitorHandle* omh_p, oop obj);
static const char* inflate_cause_name(const InflateCause cause);
// Returns the identity hash value for an oop
// NOTE: It may cause monitor inflation
static intptr_t identity_hash_value_for(Handle obj);
@@ -124,64 +132,88 @@
// GC: we current use aggressive monitor deflation policy
// 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(DeflateMonitorCounters* counters);
+ static void deflate_idle_monitors_using_JT();
+ static void deflate_global_idle_monitors_using_JT();
+ static void deflate_per_thread_idle_monitors_using_JT(JavaThread* target);
+ static void deflate_common_idle_monitors_using_JT(bool is_global, JavaThread* target);
static void deflate_thread_local_monitors(Thread* thread, DeflateMonitorCounters* counters);
static void prepare_deflate_idle_monitors(DeflateMonitorCounters* counters);
static void finish_deflate_idle_monitors(DeflateMonitorCounters* counters);
// For a given monitor list: global or per-thread, deflate idle monitors
- static int deflate_monitor_list(ObjectMonitor** list_p,
+ static int deflate_monitor_list(ObjectMonitor* volatile * list_p,
+ int volatile * count_p,
ObjectMonitor** free_head_p,
ObjectMonitor** free_tail_p);
+ // For a given in-use monitor list: global or per-thread, deflate idle
+ // monitors using a JavaThread.
+ static int deflate_monitor_list_using_JT(ObjectMonitor* volatile * list_p,
+ int volatile * count_p,
+ ObjectMonitor** free_head_p,
+ ObjectMonitor** free_tail_p,
+ ObjectMonitor** saved_mid_in_use_p);
static bool deflate_monitor(ObjectMonitor* mid, oop obj,
ObjectMonitor** free_head_p,
ObjectMonitor** free_tail_p);
- static bool is_cleanup_needed();
+ static bool deflate_monitor_using_JT(ObjectMonitor* mid,
+ ObjectMonitor** free_head_p,
+ ObjectMonitor** free_tail_p);
+ static bool is_async_deflation_needed();
+ static bool is_safepoint_deflation_needed();
+ static bool is_async_deflation_requested() { return _is_async_deflation_requested; }
+ static bool is_special_deflation_requested() { return _is_special_deflation_requested; }
+ static void set_is_async_deflation_requested(bool new_value) { _is_async_deflation_requested = new_value; }
+ static void set_is_special_deflation_requested(bool new_value) { _is_special_deflation_requested = new_value; }
+ static jlong time_since_last_async_deflation_ms();
static void oops_do(OopClosure* f);
// Process oops in thread local used monitors
static void thread_local_used_oops_do(Thread* thread, OopClosure* f);
// debugging
static void audit_and_print_stats(bool on_exit);
static void chk_free_entry(JavaThread* jt, ObjectMonitor* n,
outputStream * out, int *error_cnt_p);
static void chk_global_free_list_and_count(outputStream * out,
int *error_cnt_p);
+ static void chk_global_wait_list_and_count(outputStream * out,
+ int *error_cnt_p);
static void chk_global_in_use_list_and_count(outputStream * out,
int *error_cnt_p);
static void chk_in_use_entry(JavaThread* jt, ObjectMonitor* n,
outputStream * out, int *error_cnt_p);
static void chk_per_thread_in_use_list_and_count(JavaThread *jt,
outputStream * out,
int *error_cnt_p);
static void chk_per_thread_free_list_and_count(JavaThread *jt,
outputStream * out,
int *error_cnt_p);
- static void log_in_use_monitor_details(outputStream * out, bool on_exit);
+ static void log_in_use_monitor_details(outputStream * out);
static int log_monitor_list_counts(outputStream * out);
static int verify_objmon_isinpool(ObjectMonitor *addr) PRODUCT_RETURN0;
+ static void do_safepoint_work(DeflateMonitorCounters* counters);
+
private:
friend class SynchronizerTest;
enum { _BLOCKSIZE = 128 };
// global list of blocks of monitors
static PaddedObjectMonitor* volatile g_block_list;
- // global monitor free list
- static ObjectMonitor* volatile g_free_list;
- // global monitor in-use list, for moribund threads,
- // monitors they inflated need to be scanned for deflation
- static ObjectMonitor* volatile g_om_in_use_list;
- // count of entries in g_om_in_use_list
- static int g_om_in_use_count;
+ static volatile bool _is_async_deflation_requested;
+ static volatile bool _is_special_deflation_requested;
+ static jlong _last_async_deflation_time_ns;
+
+ // Function to prepend new blocks to the appropriate lists:
+ static void prepend_block_to_lists(PaddedObjectMonitor* new_blk);
// Process oops in all global used monitors (i.e. moribund thread's monitors)
static void global_used_oops_do(OopClosure* f);
// Process oops in monitors on the given list
- static void list_oops_do(ObjectMonitor* list, OopClosure* f);
+ static void list_oops_do(ObjectMonitor* list, int count, OopClosure* f);
// Support for SynchronizerTest access to GVars fields:
static u_char* get_gvars_addr();
static u_char* get_gvars_hc_sequence_addr();
static size_t get_gvars_size();
< prev index next >