Revision: 11963
Author: [email protected]
Date: Mon Jul 2 04:41:00 2012
Log: Merged r11900, r11901, r11904 into 3.11 branch.
Adjust idle notification handler to do full GC at the end of idle round in
order to compact code space.
Adapt fragmentation heuristics for over reserved pages.
Fix lazy sweeping heuristics to prevent old-space expansion.
BUG=v8:2194
[email protected]
Review URL: https://chromiumcodereview.appspot.com/10699051
http://code.google.com/p/v8/source/detail?r=11963
Modified:
/branches/3.11/src/heap.cc
/branches/3.11/src/mark-compact.cc
/branches/3.11/src/version.cc
/branches/3.11/test/cctest/test-alloc.cc
/branches/3.11/test/cctest/test-heap.cc
=======================================
--- /branches/3.11/src/heap.cc Wed Jun 13 04:51:58 2012
+++ /branches/3.11/src/heap.cc Mon Jul 2 04:41:00 2012
@@ -5013,7 +5013,11 @@
bool Heap::IdleNotification(int hint) {
+ // Hints greater than this value indicate that
+ // the embedder is requesting a lot of GC work.
const int kMaxHint = 1000;
+ // Minimal hint that allows to do full GC.
+ const int kMinHintForFullGC = 100;
intptr_t size_factor = Min(Max(hint, 20), kMaxHint) / 4;
// The size factor is in range [5..250]. The numbers here are chosen from
// experiments. If you changes them, make sure to test with
@@ -5081,16 +5085,30 @@
mark_sweeps_since_idle_round_started_ += new_mark_sweeps;
ms_count_at_last_idle_notification_ = ms_count_;
- if (mark_sweeps_since_idle_round_started_ >= kMaxMarkSweepsInIdleRound) {
+ int remaining_mark_sweeps = kMaxMarkSweepsInIdleRound -
+ mark_sweeps_since_idle_round_started_;
+
+ if (remaining_mark_sweeps <= 0) {
FinishIdleRound();
return true;
}
if (incremental_marking()->IsStopped()) {
- incremental_marking()->Start();
- }
-
- AdvanceIdleIncrementalMarking(step_size);
+ // If there are no more than two GCs left in this idle round and we are
+ // allowed to do a full GC, then make those GCs full in order to
compact
+ // the code space.
+ // TODO(ulan): Once we enable code compaction for incremental marking,
+ // we can get rid of this special case and always start incremental
marking.
+ if (remaining_mark_sweeps <= 2 && hint >= kMinHintForFullGC) {
+ CollectAllGarbage(kReduceMemoryFootprintMask,
+ "idle notification: finalize idle round");
+ } else {
+ incremental_marking()->Start();
+ }
+ }
+ if (!incremental_marking()->IsStopped()) {
+ AdvanceIdleIncrementalMarking(step_size);
+ }
return false;
}
=======================================
--- /branches/3.11/src/mark-compact.cc Wed Jun 13 04:51:58 2012
+++ /branches/3.11/src/mark-compact.cc Mon Jul 2 04:41:00 2012
@@ -500,12 +500,10 @@
space->identity() == OLD_DATA_SPACE ||
space->identity() == CODE_SPACE);
+ static const int kMaxMaxEvacuationCandidates = 1000;
int number_of_pages = space->CountTotalPages();
-
- const int kMaxMaxEvacuationCandidates = 1000;
- int max_evacuation_candidates = Min(
- kMaxMaxEvacuationCandidates,
- static_cast<int>(sqrt(static_cast<double>(number_of_pages / 2)) + 1));
+ int max_evacuation_candidates =
+ static_cast<int>(sqrt(static_cast<double>(number_of_pages / 2)) + 1);
if (FLAG_stress_compaction || FLAG_always_compact) {
max_evacuation_candidates = kMaxMaxEvacuationCandidates;
@@ -535,17 +533,28 @@
intptr_t over_reserved = reserved - space->SizeOfObjects();
static const intptr_t kFreenessThreshold = 50;
- if (over_reserved >= 2 * space->AreaSize() &&
- reduce_memory_footprint_) {
- mode = REDUCE_MEMORY_FOOTPRINT;
-
- // We expect that empty pages are easier to compact so slightly bump
the
- // limit.
- max_evacuation_candidates += 2;
-
- if (FLAG_trace_fragmentation) {
- PrintF("Estimated over reserved memory: %.1f MB (setting
threshold %d)\n",
+ if (over_reserved >= 2 * space->AreaSize()) {
+
+ // If reduction of memory footprint was requested, we are aggressive
+ // about choosing pages to free. We expect that half-empty pages
+ // are easier to compact so slightly bump the limit.
+ if (reduce_memory_footprint_) {
+ mode = REDUCE_MEMORY_FOOTPRINT;
+ max_evacuation_candidates += 2;
+ }
+
+ // If over-usage is very high (more than a third of the space), we
+ // try to free all mostly empty pages. We expect that almost empty
+ // pages are even easier to compact so bump the limit even more.
+ if (over_reserved > reserved / 3) {
+ mode = REDUCE_MEMORY_FOOTPRINT;
+ max_evacuation_candidates *= 2;
+ }
+
+ if (FLAG_trace_fragmentation && mode == REDUCE_MEMORY_FOOTPRINT) {
+ PrintF("Estimated over reserved memory: %.1f / %.1f MB
(threshold %d)\n",
static_cast<double>(over_reserved) / MB,
+ static_cast<double>(reserved) / MB,
static_cast<int>(kFreenessThreshold));
}
}
@@ -554,6 +563,9 @@
Candidate candidates[kMaxMaxEvacuationCandidates];
+ max_evacuation_candidates =
+ Min(kMaxMaxEvacuationCandidates, max_evacuation_candidates);
+
int count = 0;
int fragmentation = 0;
Candidate* least = NULL;
@@ -3817,11 +3829,6 @@
bool lazy_sweeping_active = false;
bool unused_page_present = false;
- intptr_t old_space_size = heap()->PromotedSpaceSizeOfObjects();
- intptr_t space_left =
- Min(heap()->OldGenPromotionLimit(old_space_size),
- heap()->OldGenAllocationLimit(old_space_size)) - old_space_size;
-
while (it.has_next()) {
Page* p = it.next();
@@ -3881,7 +3888,7 @@
}
freed_bytes += SweepConservatively(space, p);
pages_swept++;
- if (space_left + freed_bytes > newspace_size) {
+ if (freed_bytes > 2 * newspace_size) {
space->SetPagesToSweep(p->next_page());
lazy_sweeping_active = true;
} else {
=======================================
--- /branches/3.11/src/version.cc Fri Jun 22 08:27:14 2012
+++ /branches/3.11/src/version.cc Mon Jul 2 04:41:00 2012
@@ -35,7 +35,7 @@
#define MAJOR_VERSION 3
#define MINOR_VERSION 11
#define BUILD_NUMBER 10
-#define PATCH_LEVEL 12
+#define PATCH_LEVEL 13
// Use 1 for candidates and 0 otherwise.
// (Boolean macro values are not supported by all preprocessors.)
#define IS_CANDIDATE_VERSION 0
=======================================
--- /branches/3.11/test/cctest/test-alloc.cc Mon Apr 30 05:34:39 2012
+++ /branches/3.11/test/cctest/test-alloc.cc Mon Jul 2 04:41:00 2012
@@ -34,7 +34,8 @@
using namespace v8::internal;
-static inline void SimulateFullSpace(PagedSpace* space) {
+// Also used in test-heap.cc test cases.
+void SimulateFullSpace(PagedSpace* space) {
int old_linear_size = static_cast<int>(space->limit() - space->top());
space->Free(space->top(), old_linear_size);
space->SetTop(space->limit(), space->limit());
=======================================
--- /branches/3.11/test/cctest/test-heap.cc Fri Jun 15 05:31:06 2012
+++ /branches/3.11/test/cctest/test-heap.cc Mon Jul 2 04:41:00 2012
@@ -1898,3 +1898,42 @@
CHECK(root->IsJSObject());
CHECK(root->map()->IsMap());
}
+
+
+// Implemented in the test-alloc.cc test suite.
+void SimulateFullSpace(PagedSpace* space);
+
+
+TEST(ReleaseOverReservedPages) {
+ i::FLAG_trace_gc = true;
+ InitializeVM();
+ v8::HandleScope scope;
+ static const int number_of_test_pages = 20;
+
+ // Prepare many pages with low live-bytes count.
+ PagedSpace* old_pointer_space = HEAP->old_pointer_space();
+ CHECK_EQ(1, old_pointer_space->CountTotalPages());
+ for (int i = 0; i < number_of_test_pages; i++) {
+ AlwaysAllocateScope always_allocate;
+ SimulateFullSpace(old_pointer_space);
+ FACTORY->NewFixedArray(1, TENURED);
+ }
+ CHECK_EQ(number_of_test_pages + 1, old_pointer_space->CountTotalPages());
+
+ // Triggering one GC will cause a lot of garbage to be discovered but
+ // even spread across all allocated pages.
+ HEAP->CollectAllGarbage(Heap::kNoGCFlags, "triggered for preparation");
+ CHECK_EQ(number_of_test_pages + 1, old_pointer_space->CountTotalPages());
+
+ // Triggering subsequent GCs should cause at least half of the pages
+ // to be released to the OS after at most two cycles.
+ HEAP->CollectAllGarbage(Heap::kNoGCFlags, "triggered by test 1");
+ CHECK_GE(number_of_test_pages + 1, old_pointer_space->CountTotalPages());
+ HEAP->CollectAllGarbage(Heap::kNoGCFlags, "triggered by test 2");
+ CHECK_GE(number_of_test_pages + 1, old_pointer_space->CountTotalPages()
* 2);
+
+ // Triggering a last-resort GC should cause all pages to be released
+ // to the OS so that other processes can seize the memory.
+ HEAP->CollectAllAvailableGarbage("triggered really hard");
+ CHECK_EQ(1, old_pointer_space->CountTotalPages());
+}
--
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