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6711930: NUMA allocator: ParOld can create a hole less than minimal object size in the lgrp chunk

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The fix takes care of three issues that can create a hole less a minimal object in the lgrp chunk

Reviewed-by: ysr, apetrusenko
This commit is contained in:
Igor Veresov 2008-06-09 07:18:59 -07:00
parent 39463bb3fc
commit ed4e9a5d5c
6 changed files with 32 additions and 11 deletions
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33
hotspot/src/share/vm/gc_implementation/shared/mutableNUMASpace.cpp
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@ -599,12 +599,28 @@ void MutableNUMASpace::initialize(MemRegion mr, bool clear_space) {
// Mark the the holes in chunks below the top() as invalid.
void MutableNUMASpace::set_top(HeapWord* value) {
bool found_top = false;
for (int i = 0; i < lgrp_spaces()->length(); i++) {
for (int i = 0; i < lgrp_spaces()->length();) {
LGRPSpace *ls = lgrp_spaces()->at(i);
MutableSpace *s = ls->space();
HeapWord *top = MAX2((HeapWord*)round_down((intptr_t)s->top(), page_size()), s->bottom());
if (s->contains(value)) {
// Check if setting the chunk's top to a given value would create a hole less than
// a minimal object; assuming that's not the last chunk in which case we don't care.
if (i < lgrp_spaces()->length() - 1) {
size_t remainder = pointer_delta(s->end(), value);
const size_t minimal_object_size = oopDesc::header_size();
if (remainder < minimal_object_size && remainder > 0) {
// Add a filler object of a minimal size, it will cross the chunk boundary.
SharedHeap::fill_region_with_object(MemRegion(value, minimal_object_size));
value += minimal_object_size;
assert(!s->contains(value), "Should be in the next chunk");
// Restart the loop from the same chunk, since the value has moved
// to the next one.
continue;
}
}
if (!os::numa_has_static_binding() && top < value && top < s->end()) {
ls->add_invalid_region(MemRegion(top, value));
}
@ -620,6 +636,7 @@ void MutableNUMASpace::set_top(HeapWord* value) {
s->set_top(s->end());
}
}
i++;
}
MutableSpace::set_top(value);
}
@ -700,12 +717,14 @@ HeapWord* MutableNUMASpace::cas_allocate(size_t size) {
MutableSpace *s = lgrp_spaces()->at(i)->space();
HeapWord *p = s->cas_allocate(size);
if (p != NULL) {
size_t remainder = pointer_delta(s->end(), p);
size_t remainder = pointer_delta(s->end(), p + size);
if (remainder < (size_t)oopDesc::header_size() && remainder > 0) {
if (s->cas_deallocate(p, size)) {
// We were the last to allocate and created a fragment less than
// a minimal object.
p = NULL;
} else {
guarantee(false, "Deallocation should always succeed");
}
}
}
@ -761,10 +780,12 @@ void MutableNUMASpace::print_on(outputStream* st) const {
}
}
void MutableNUMASpace::verify(bool allow_dirty) const {
for (int i = 0; i < lgrp_spaces()->length(); i++) {
lgrp_spaces()->at(i)->space()->verify(allow_dirty);
}
void MutableNUMASpace::verify(bool allow_dirty) {
// This can be called after setting an arbitary value to the space's top,
// so an object can cross the chunk boundary. We ensure the parsablity
// of the space and just walk the objects in linear fashion.
ensure_parsability();
MutableSpace::verify(allow_dirty);
}
// Scan pages and gather stats about page placement and size.