void FreeList::getFirstNChunksFromList(size_t n, FreeList* fl) {
assert_proper_lock_protection();
assert(fl->count() == 0, "Precondition");
if (count() > 0) {
int k = 1;
fl->set_head(head());
n--;
FreeChunk* tl = head();
while (tl->next() != NULL && n > 0) {
tl = tl->next();
n--;
k++;
}
assert(tl != NULL, "Loop Inv.");
// First, fix up the list we took from.
FreeChunk* new_head = tl->next();
set_head(new_head);
set_count(count() - k);
if (new_head == NULL) {
set_tail(NULL);
} else {
new_head->linkPrev(NULL);
}
// Now we can fix up the tail.
tl->linkNext(NULL);
// And return the result.
fl->set_tail(tl);
fl->set_count(k);
}
}
// Remove this chunk from the list
void FreeList::removeChunk(FreeChunk*fc) {
assert_proper_lock_protection();
assert(head() != NULL, "Remove from empty list");
assert(fc != NULL, "Remove a NULL chunk");
assert(size() == fc->size(), "Wrong list");
assert(head() == NULL || head()->prev() == NULL, "list invariant");
assert(tail() == NULL || tail()->next() == NULL, "list invariant");
FreeChunk* prevFC = fc->prev();
FreeChunk* nextFC = fc->next();
if (nextFC != NULL) {
// The chunk fc being removed has a "next". Set the "next" to the
// "prev" of fc.
nextFC->linkPrev(prevFC);
} else { // removed tail of list
link_tail(prevFC);
}
if (prevFC == NULL) { // removed head of list
link_head(nextFC);
assert(nextFC == NULL || nextFC->prev() == NULL,
"Prev of head should be NULL");
} else {
prevFC->linkNext(nextFC);
assert(tail() != prevFC || prevFC->next() == NULL,
"Next of tail should be NULL");
}
decrement_count();
assert(((head() == NULL) + (tail() == NULL) + (count() == 0)) % 3 == 0,
"H/T/C Inconsistency");
// clear next and prev fields of fc, debug only
NOT_PRODUCT(
fc->linkPrev(NULL);
fc->linkNext(NULL);
)
FreeChunk* FreeList::getChunkAtHead() {
assert_proper_lock_protection();
assert(head() == NULL || head()->prev() == NULL, "list invariant");
assert(tail() == NULL || tail()->next() == NULL, "list invariant");
FreeChunk* fc = head();
if (fc != NULL) {
FreeChunk* nextFC = fc->next();
if (nextFC != NULL) {
// The chunk fc being removed has a "next". Set the "next" to the
// "prev" of fc.
nextFC->linkPrev(NULL);
} else { // removed tail of list
link_tail(NULL);
}
link_head(nextFC);
decrement_count();
}
assert(head() == NULL || head()->prev() == NULL, "list invariant");
assert(tail() == NULL || tail()->next() == NULL, "list invariant");
return fc;
}
TreeList* TreeList::removeChunkReplaceIfNeeded(TreeChunk* tc) {
TreeList* retTL = this;
FreeChunk* list = head();
assert(!list || list != list->next(), "Chunk on list twice");
assert(tc != NULL, "Chunk being removed is NULL");
assert(parent() == NULL || this == parent()->left() ||
this == parent()->right(), "list is inconsistent");
assert(tc->isFree(), "Header is not marked correctly");
assert(head() == NULL || head()->prev() == NULL, "list invariant");
assert(tail() == NULL || tail()->next() == NULL, "list invariant");
FreeChunk* prevFC = tc->prev();
TreeChunk* nextTC = TreeChunk::as_TreeChunk(tc->next());
assert(list != NULL, "should have at least the target chunk");
// Is this the first item on the list?
if (tc == list) {
// The "getChunk..." functions for a TreeList will not return the
// first chunk in the list unless it is the last chunk in the list
// because the first chunk is also acting as the tree node.
// When coalescing happens, however, the first chunk in the a tree
// list can be the start of a free range. Free ranges are removed
// from the free lists so that they are not available to be
// allocated when the sweeper yields (giving up the free list lock)
// to allow mutator activity. If this chunk is the first in the
// list and is not the last in the list, do the work to copy the
// TreeList from the first chunk to the next chunk and update all
// the TreeList pointers in the chunks in the list.
if (nextTC == NULL) {
assert(prevFC == NULL, "Not last chunk in the list")
set_tail(NULL);
set_head(NULL);
} else {
debug_only(
if (PrintGC && Verbose) {
gclog_or_tty->print_cr("Removing first but not only chunk in TreeList");
gclog_or_tty->print_cr("Node: " INTPTR_FORMAT " parent: " INTPTR_FORMAT
" right: " INTPTR_FORMAT " left: " INTPTR_FORMAT,
tc, tc->list()->parent(), tc->list()->right(), tc->list()->left());
gclog_or_tty->print_cr("Next before: " INTPTR_FORMAT " parent: "
INTPTR_FORMAT " right: " INTPTR_FORMAT " left: " INTPTR_FORMAT,
nextTC, nextTC->list()->parent(), nextTC->list()->right(),
nextTC->list()->left());
gclog_or_tty->print_cr(" head: " INTPTR_FORMAT " tail: "
INTPTR_FORMAT, nextTC->list()->head(), nextTC->list()->tail());
}
)
// copy embedded list.
nextTC->set_embedded_list(tc->embedded_list());
retTL = nextTC->embedded_list();
// Fix the pointer to the list in each chunk in the list.
// This can be slow for a long list. Consider having
// an option that does not allow the first chunk on the
// list to be coalesced.
for (TreeChunk* curTC = nextTC; curTC != NULL;
curTC = TreeChunk::as_TreeChunk(curTC->next())) {
curTC->set_list(retTL);
}
// Fix the parent to point to the new TreeList.
if (retTL->parent() != NULL) {
if (this == retTL->parent()->left()) {
retTL->parent()->setLeft(retTL);
} else {
assert(this == retTL->parent()->right(), "Parent is incorrect");
retTL->parent()->setRight(retTL);
}
}
// Fix the children's parent pointers to point to the
// new list.
assert(right() == retTL->right(), "Should have been copied");
if (retTL->right() != NULL) {
retTL->right()->setParent(retTL);
}
assert(left() == retTL->left(), "Should have been copied");
if (retTL->left() != NULL) {
retTL->left()->setParent(retTL);
}
retTL->link_head(nextTC);
debug_only(
if (PrintGC && Verbose) {
gclog_or_tty->print_cr("Next after: " INTPTR_FORMAT " parent: "
INTPTR_FORMAT " right: " INTPTR_FORMAT " left: " INTPTR_FORMAT,
nextTC, nextTC->list()->parent(), nextTC->list()->right(),
nextTC->list()->left());
gclog_or_tty->print_cr(" head: " INTPTR_FORMAT " tail: "
INTPTR_FORMAT, nextTC->list()->head(), nextTC->list()->tail());
}
)
assert(nextTC->isFree(), "Should be a free chunk");
}
