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comparison src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp @ 8853:2e093b564241

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7014552: gc/lock/jni/jnilockXXX works too slow on 1-processor machine Summary: Keep a counter of how many times we were stalled by the GC locker, add a diagnostic flag which sets the limit. Reviewed-by: brutisso, ehelin, johnc
author mgerdin
date Thu, 28 Mar 2013 10:27:28 +0100
parents 3c226052f7dc
children 7b835924c31c
comparison
equal deleted inserted replaced
8827:42e370795a39 8853:2e093b564241
324 324
325 HeapWord* result = young_gen()->allocate(size); 325 HeapWord* result = young_gen()->allocate(size);
326 326
327 uint loop_count = 0; 327 uint loop_count = 0;
328 uint gc_count = 0; 328 uint gc_count = 0;
329 int gclocker_stalled_count = 0;
329 330
330 while (result == NULL) { 331 while (result == NULL) {
331 // We don't want to have multiple collections for a single filled generation. 332 // We don't want to have multiple collections for a single filled generation.
332 // To prevent this, each thread tracks the total_collections() value, and if 333 // To prevent this, each thread tracks the total_collections() value, and if
333 // the count has changed, does not do a new collection. 334 // the count has changed, does not do a new collection.
352 result = mem_allocate_old_gen(size); 353 result = mem_allocate_old_gen(size);
353 if (result != NULL) { 354 if (result != NULL) {
354 return result; 355 return result;
355 } 356 }
356 357
358 if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
359 return NULL;
360 }
361
357 // Failed to allocate without a gc. 362 // Failed to allocate without a gc.
358 if (GC_locker::is_active_and_needs_gc()) { 363 if (GC_locker::is_active_and_needs_gc()) {
359 // If this thread is not in a jni critical section, we stall 364 // If this thread is not in a jni critical section, we stall
360 // the requestor until the critical section has cleared and 365 // the requestor until the critical section has cleared and
361 // GC allowed. When the critical section clears, a GC is 366 // GC allowed. When the critical section clears, a GC is
364 // rather than causing more, now probably unnecessary, GC attempts. 369 // rather than causing more, now probably unnecessary, GC attempts.
365 JavaThread* jthr = JavaThread::current(); 370 JavaThread* jthr = JavaThread::current();
366 if (!jthr->in_critical()) { 371 if (!jthr->in_critical()) {
367 MutexUnlocker mul(Heap_lock); 372 MutexUnlocker mul(Heap_lock);
368 GC_locker::stall_until_clear(); 373 GC_locker::stall_until_clear();
374 gclocker_stalled_count += 1;
369 continue; 375 continue;
370 } else { 376 } else {
371 if (CheckJNICalls) { 377 if (CheckJNICalls) {
372 fatal("Possible deadlock due to allocating while" 378 fatal("Possible deadlock due to allocating while"
373 " in jni critical section"); 379 " in jni critical section");