Mercurial > hg > truffle
changeset 1313:664ae0c5e0e5
6755988: G1: assert(new_obj != 0 || ... "should be forwarded")
Summary: A TLAB became large enough to be considered a humongous object allowing multiple objects to be allocated in a humongous region, which violates a basic assumption about humongous regions. The changes ensure that TLABs cannot be regarded as humongous.
Reviewed-by: iveresov, tonyp
author | johnc |
---|---|
date | Thu, 11 Mar 2010 11:44:43 -0800 |
parents | 94946bdf36bd |
children | 3f0549ed0c98 |
files | src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp |
diffstat | 2 files changed, 18 insertions(+), 10 deletions(-) [+] |
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--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Mon Mar 15 02:56:45 2010 -0700 +++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Thu Mar 11 11:44:43 2010 -0800 @@ -2102,18 +2102,21 @@ size_t G1CollectedHeap::unsafe_max_tlab_alloc(Thread* ignored) const { // Return the remaining space in the cur alloc region, but not less than // the min TLAB size. - // Also, no more than half the region size, since we can't allow tlabs to - // grow big enough to accomodate humongous objects. - - // We need to story it locally, since it might change between when we - // test for NULL and when we use it later. + + // Also, this value can be at most the humongous object threshold, + // since we can't allow tlabs to grow big enough to accomodate + // humongous objects. + + // We need to store the cur alloc region locally, since it might change + // between when we test for NULL and when we use it later. ContiguousSpace* cur_alloc_space = _cur_alloc_region; + size_t max_tlab_size = _humongous_object_threshold_in_words * wordSize; + if (cur_alloc_space == NULL) { - return HeapRegion::GrainBytes/2; + return max_tlab_size; } else { - return MAX2(MIN2(cur_alloc_space->free(), - (size_t)(HeapRegion::GrainBytes/2)), - (size_t)MinTLABSize); + return MIN2(MAX2(cur_alloc_space->free(), (size_t)MinTLABSize), + max_tlab_size); } }
--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Mon Mar 15 02:56:45 2010 -0700 +++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Thu Mar 11 11:44:43 2010 -0800 @@ -1055,7 +1055,12 @@ // Returns "true" iff the given word_size is "very large". static bool isHumongous(size_t word_size) { - return word_size >= _humongous_object_threshold_in_words; + // Note this has to be strictly greater-than as the TLABs + // are capped at the humongous thresold and we want to + // ensure that we don't try to allocate a TLAB as + // humongous and that we don't allocate a humongous + // object in a TLAB. + return word_size > _humongous_object_threshold_in_words; } // Update mod union table with the set of dirty cards.