Revision: 8621
Author: [email protected]
Date: Wed Jul 13 00:22:45 2011
Log: Chang Heap::FreeQueuedChunks to prepare queued large chunks for
StoreBuffer::Filter.
We split large chunks into separate smaller kPageSize aligned pieces to
ensure that
MemoryChunk::FromAnyPointerAddress would be able to find chunk containing
slot even if the chunk was unlinked from the list of large chunks.
[email protected]
BUG=v8:1554
Review URL: http://codereview.chromium.org/7356005
http://code.google.com/p/v8/source/detail?r=8621
Modified:
/branches/experimental/gc/src/heap.cc
=======================================
--- /branches/experimental/gc/src/heap.cc Tue Jul 12 16:04:25 2011
+++ /branches/experimental/gc/src/heap.cc Wed Jul 13 00:22:45 2011
@@ -5975,6 +5975,31 @@
for (chunk = chunks_queued_for_free_; chunk != NULL; chunk = next) {
next = chunk->next_chunk();
chunk->SetFlag(MemoryChunk::ABOUT_TO_BE_FREED);
+
+ if (chunk->owner()->identity() == LO_SPACE) {
+ // StoreBuffer::Filter relies on MemoryChunk::FromAnyPointerAddress.
+ // If FromAnyPointerAddress encounters a slot that belongs to a large
+ // chunk queued for deletion it will fail to find the chunk because
+ // it try to perform a search in the list of pages owned by of the
large
+ // object space and queued chunks were detached from that list.
+ // To work around this we split large chunk into normal kPageSize
aligned
+ // pieces and initialize owner field and flags of every piece.
+ // If FromAnyPointerAddress encounteres a slot that belongs to one of
+ // these smaller pieces it will treat it as a slot on a normal Page.
+ MemoryChunk* inner = MemoryChunk::FromAddress(
+ chunk->address() + Page::kPageSize);
+ MemoryChunk* inner_last = MemoryChunk::FromAddress(
+ chunk->address() + chunk->size() - 1);
+ while (inner <= inner_last) {
+ // Size of a large chunk is always a multiple of
+ // OS::AllocationAlignment() so there is always
+ // enough space for a fake MemoryChunk header.
+ inner->set_owner(lo_space());
+ inner->SetFlag(MemoryChunk::ABOUT_TO_BE_FREED);
+ inner = MemoryChunk::FromAddress(
+ inner->address() + Page::kPageSize);
+ }
+ }
}
isolate_->heap()->store_buffer()->Filter(MemoryChunk::ABOUT_TO_BE_FREED);
for (chunk = chunks_queued_for_free_; chunk != NULL; chunk = next) {
--
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