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8034852: Shrinking of Metaspace high-water-mark causes incorrect OutOfMemoryErrors or back-to-back GCs

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Reviewed-by: jmasa, pliden, stefank
This commit is contained in:
Erik Helin 2014-05-09 09:59:39 +02:00
parent 09c2deeb5a
commit 8629eeb403
1 changed files with 12 additions and 5 deletions
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17
hotspot/src/share/vm/memory/metaspace.cpp
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@ -1431,10 +1431,9 @@ size_t MetaspaceGC::allowed_expansion() {
}
size_t capacity_until_gc = capacity_until_GC();
if (capacity_until_gc <= committed_bytes) {
return 0;
}
assert(capacity_until_gc >= committed_bytes,
err_msg("capacity_until_gc: " SIZE_FORMAT " < committed_bytes: " SIZE_FORMAT,
capacity_until_gc, committed_bytes));
size_t left_until_GC = capacity_until_gc - committed_bytes;
size_t left_to_commit = MIN2(left_until_GC, left_until_max);
@ -1447,7 +1446,15 @@ void MetaspaceGC::compute_new_size() {
uint current_shrink_factor = _shrink_factor;
_shrink_factor = 0;
const size_t used_after_gc = MetaspaceAux::capacity_bytes();
// Using committed_bytes() for used_after_gc is an overestimation, since the
// chunk free lists are included in committed_bytes() and the memory in an
// un-fragmented chunk free list is available for future allocations.
// However, if the chunk free lists becomes fragmented, then the memory may
// not be available for future allocations and the memory is therefore "in use".
// Including the chunk free lists in the definition of "in use" is therefore
// necessary. Not including the chunk free lists can cause capacity_until_GC to
// shrink below committed_bytes() and this has caused serious bugs in the past.
const size_t used_after_gc = MetaspaceAux::committed_bytes();
const size_t capacity_until_GC = MetaspaceGC::capacity_until_GC();
const double minimum_free_percentage = MinMetaspaceFreeRatio / 100.0;