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[heap] Cleanup OLD_TO_SHARED slots in sweeper

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Sweeper needs to clean up slots in the OLD_TO_SHARED remembered set
as well in the future. Unlike OLD_TO_NEW or OLD_TO_OLD this remembered
set will not be reset after a full GC. So we will have to remove from it
both during and after a full GC when sweeping.

However in the current implementation we still reset this remembered set
in a shared GC. This only works because we scan all client heaps
during a shared GC anyways to rebuild the remembered set. We will get
rid of that when all required write barriers are implemented.

Bug: v8:11708
Change-Id: Ib891a882fdf70671a483c8662408cf64e72134c6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3574546
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79874}
This commit is contained in:
Dominik Inführ 2022-04-08 10:19:26 +02:00 committed by V8 LUCI CQ
parent e0b8ce19f3
commit 55f6a97366
1 changed files with 9 additions and 0 deletions
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9
src/heap/sweeper.cc
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@ -272,6 +272,11 @@ V8_INLINE void Sweeper::CleanupRememberedSetEntriesForFreedMemory(
DCHECK_NULL(page->slot_set<OLD_TO_OLD>());
}
// Old-to-shared isn't reset after a full GC, so needs to be cleaned both
// during and after a full GC.
RememberedSet<OLD_TO_SHARED>::RemoveRange(page, free_start, free_end,
SlotSet::KEEP_EMPTY_BUCKETS);
if (record_free_ranges) {
free_ranges_map->insert(std::pair<uint32_t, uint32_t>(
static_cast<uint32_t>(free_start - page->address()),
@ -291,6 +296,8 @@ void Sweeper::CleanupInvalidTypedSlotsOfFreeRanges(
// Also code objects are never right-trimmed, so there cannot be any slots
// in a free range.
page->AssertNoInvalidTypedSlots<OLD_TO_OLD>(free_ranges_map);
page->ClearInvalidTypedSlots<OLD_TO_SHARED>(free_ranges_map);
return;
}
@ -300,6 +307,7 @@ void Sweeper::CleanupInvalidTypedSlotsOfFreeRanges(
// could create new slots but not in a free range.
page->AssertNoInvalidTypedSlots<OLD_TO_NEW>(free_ranges_map);
DCHECK_NULL(page->typed_slot_set<OLD_TO_OLD>());
page->ClearInvalidTypedSlots<OLD_TO_SHARED>(free_ranges_map);
}
void Sweeper::ClearMarkBitsAndHandleLivenessStatistics(
@ -356,6 +364,7 @@ int Sweeper::RawSweep(Page* p, FreeListRebuildingMode free_list_mode,
bool record_free_ranges = p->typed_slot_set<OLD_TO_NEW>() != nullptr ||
p->typed_slot_set<OLD_TO_OLD>() != nullptr ||
p->typed_slot_set<OLD_TO_SHARED>() != nullptr ||
DEBUG_BOOL;
// Clean invalidated slots during the final atomic pause. After resuming