archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-09-20 19:14:38 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

8023021: Unnecessary clearing of the card table introduced by the fix for JDK-8023013

Browse source 
Reviewed-by: stefank, ehelin
This commit is contained in:
Bengt Rutisson 2013-08-15 10:05:50 +02:00
parent dab6bdc071
commit c144b8c30f
4 changed files with 17 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

23
hotspot/src/share/vm/memory/cardTableRS.cpp
View file

@ -310,32 +310,27 @@ void CardTableRS::younger_refs_in_space_iterate(Space* sp,
_ct_bs->non_clean_card_iterate_possibly_parallel(sp, urasm, cl, this);
}
void CardTableRS::clear_into_younger(Generation* gen) {
GenCollectedHeap* gch = GenCollectedHeap::heap();
// Generations younger than gen have been evacuated. We can clear
// card table entries for gen (we know that it has no pointers
// to younger gens) and for those below. The card tables for
// the youngest gen need never be cleared.
void CardTableRS::clear_into_younger(Generation* old_gen) {
assert(old_gen->level() == 1, "Should only be called for the old generation");
// The card tables for the youngest gen need never be cleared.
// There's a bit of subtlety in the clear() and invalidate()
// methods that we exploit here and in invalidate_or_clear()
// below to avoid missing cards at the fringes. If clear() or
// invalidate() are changed in the future, this code should
// be revisited. 20040107.ysr
Generation* old_gen = gen;
clear(old_gen->prev_used_region());
Generation* young_gen = gch->prev_gen(old_gen);
clear(young_gen->prev_used_region());
}
void CardTableRS::invalidate_or_clear(Generation* gen) {
// For generation gen invalidate the cards for the currently
// occupied part of that generation and clear the cards for the
void CardTableRS::invalidate_or_clear(Generation* old_gen) {
assert(old_gen->level() == 1, "Should only be called for the old generation");
// Invalidate the cards for the currently occupied part of
// the old generation and clear the cards for the
// unoccupied part of the generation (if any, making use
// of that generation's prev_used_region to determine that
// region). No need to do anything for the youngest
// generation. Also see note#20040107.ysr above.
MemRegion used_mr = gen->used_region();
MemRegion to_be_cleared_mr = gen->prev_used_region().minus(used_mr);
MemRegion used_mr = old_gen->used_region();
MemRegion to_be_cleared_mr = old_gen->prev_used_region().minus(used_mr);
if (!to_be_cleared_mr.is_empty()) {
clear(to_be_cleared_mr);
}