infernap12/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2026-02-26 18:20:28 +00:00
Code Issues Packages Projects Releases Wiki Activity

8260200: G1: Remove unnecessary update in FreeRegionList::remove_starting_at

Browse Source 
Reviewed-by: ayang, sjohanss, tschatzl
This commit is contained in:
Hamlin Li 2021-01-28 00:45:16 +00:00
parent c7661aed6f
commit 7030d2e026
2 changed files with 40 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
src/hotspot/share/gc/g1/heapRegionSet.cpp
View File

@ -227,40 +227,47 @@ void FreeRegionList::add_ordered(FreeRegionList* from_list) {
add_list_common_end(from_list);
}
#ifdef ASSERT
void FreeRegionList::verify_region_to_remove(HeapRegion* curr, HeapRegion* next) {
assert_free_region_list(_head != next, "invariant");
if (next != NULL) {
assert_free_region_list(next->prev() == curr, "invariant");
assert_free_region_list(_tail != curr, "invariant");
} else {
assert_free_region_list(_tail == curr, "invariant");
}
HeapRegion* prev = curr->prev();
if (prev == NULL) {
assert_free_region_list(_head == curr, "invariant");
} else {
assert_free_region_list(_head != curr, "invariant");
}
}
#endif
void FreeRegionList::remove_starting_at(HeapRegion* first, uint num_regions) {
check_mt_safety();
assert_free_region_list(num_regions >= 1, "pre-condition");
assert_free_region_list(!is_empty(), "pre-condition");
assert_free_region_list(length() >= num_regions, "pre-condition");
verify_optional();
DEBUG_ONLY(uint old_length = length();)
// prev points to the node right before first or null when first == _head
HeapRegion* const prev = first->prev();
// next points to the node right after first or null when first == _tail,
// and after the while loop below, next should point to the next node right
// after the removed sublist, or null if the sublist contains _tail.
HeapRegion* next = first->next();
HeapRegion* curr = first;
uint count = 0;
while (count < num_regions) {
verify_region(curr);
HeapRegion* next = curr->next();
HeapRegion* prev = curr->prev();
next = curr->next();
verify_region_to_remove(curr, next);
assert(count < num_regions,
"[%s] should not come across more regions "
"pending for removal than num_regions: %u",
name(), num_regions);
if (prev == NULL) {
assert_free_region_list(_head == curr, "invariant");
_head = next;
} else {
assert_free_region_list(_head != curr, "invariant");
prev->set_next(next);
}
if (next == NULL) {
assert_free_region_list(_tail == curr, "invariant");
_tail = prev;
} else {
assert_free_region_list(_tail != curr, "invariant");
next->set_prev(prev);
}
if (_last == curr) {
_last = NULL;
}
@ -276,6 +283,17 @@ void FreeRegionList::remove_starting_at(HeapRegion* first, uint num_regions) {
curr = next;
}
if (prev == NULL) {
_head = next;
} else {
prev->set_next(next);
}
if (next == NULL) {
_tail = prev;
} else {
next->set_prev(prev);
}
assert(count == num_regions,
"[%s] count: %u should be == num_regions: %u",
name(), count, num_regions);

1
src/hotspot/share/gc/g1/heapRegionSet.hpp
View File

@ -184,6 +184,7 @@ private:
void add_list_common_start(FreeRegionList* from_list);
void add_list_common_end(FreeRegionList* from_list);
void verify_region_to_remove(HeapRegion* curr, HeapRegion* next) NOT_DEBUG_RETURN;
protected:
// See the comment for HeapRegionSetBase::clear()
virtual void clear();