AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

Implement and enable zapping of code space while sweeping.

Browse Source 
R=danno@chromium.org, hpayer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/181513004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19568 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
mstarzinger@chromium.org 2014-02-27 09:36:29 +00:00
parent 44da745247
commit 947a5e6b3a
2 changed files with 39 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/flag-definitions.h
View File

@ -572,6 +572,8 @@ DEFINE_bool(cleanup_code_caches_at_gc, true,
DEFINE_bool(use_marking_progress_bar, true,
"Use a progress bar to scan large objects in increments when "
"incremental marking is active.")
DEFINE_bool(zap_code_space, true,
"Zap free memory in code space with 0xCC while sweeping.")
DEFINE_int(random_seed, 0,
"Default seed for initializing random generator "
"(0, the default, means to use system random).")

44
src/mark-compact.cc
View File

@ -3204,13 +3204,21 @@ enum SkipListRebuildingMode {
};
enum FreeSpaceTreatmentMode {
IGNORE_FREE_SPACE,
ZAP_FREE_SPACE
};
// Sweep a space precisely. After this has been done the space can
// be iterated precisely, hitting only the live objects. Code space
// is always swept precisely because we want to be able to iterate
// over it. Map space is swept precisely, because it is not compacted.
// Slots in live objects pointing into evacuation candidates are updated
// if requested.
template<SweepingMode sweeping_mode, SkipListRebuildingMode skip_list_mode>
template<SweepingMode sweeping_mode,
SkipListRebuildingMode skip_list_mode,
FreeSpaceTreatmentMode free_space_mode>
static void SweepPrecisely(PagedSpace* space,
Page* p,
ObjectVisitor* v) {
@ -3244,6 +3252,9 @@ static void SweepPrecisely(PagedSpace* space,
for ( ; live_objects != 0; live_objects--) {
Address free_end = cell_base + offsets[live_index++] * kPointerSize;
if (free_end != free_start) {
if (free_space_mode == ZAP_FREE_SPACE) {
memset(free_start, 0xcc, static_cast<int>(free_end - free_start));
}
space->Free(free_start, static_cast<int>(free_end - free_start));
#ifdef ENABLE_GDB_JIT_INTERFACE
if (FLAG_gdbjit && space->identity() == CODE_SPACE) {
@ -3275,6 +3286,9 @@ static void SweepPrecisely(PagedSpace* space,
*cell = 0;
}
if (free_start != p->area_end()) {
if (free_space_mode == ZAP_FREE_SPACE) {
memset(free_start, 0xcc, static_cast<int>(p->area_end() - free_start));
}
space->Free(free_start, static_cast<int>(p->area_end() - free_start));
#ifdef ENABLE_GDB_JIT_INTERFACE
if (FLAG_gdbjit && space->identity() == CODE_SPACE) {
@ -3520,12 +3534,23 @@ void MarkCompactCollector::EvacuateNewSpaceAndCandidates() {
SweepConservatively<SWEEP_SEQUENTIALLY>(space, NULL, p);
break;
case OLD_POINTER_SPACE:
SweepPrecisely<SWEEP_AND_VISIT_LIVE_OBJECTS, IGNORE_SKIP_LIST>(
SweepPrecisely<SWEEP_AND_VISIT_LIVE_OBJECTS,
IGNORE_SKIP_LIST,
IGNORE_FREE_SPACE>(
space, p, &updating_visitor);
break;
case CODE_SPACE:
SweepPrecisely<SWEEP_AND_VISIT_LIVE_OBJECTS, REBUILD_SKIP_LIST>(
space, p, &updating_visitor);
if (FLAG_zap_code_space) {
SweepPrecisely<SWEEP_AND_VISIT_LIVE_OBJECTS,
REBUILD_SKIP_LIST,
ZAP_FREE_SPACE>(
space, p, &updating_visitor);
} else {
SweepPrecisely<SWEEP_AND_VISIT_LIVE_OBJECTS,
REBUILD_SKIP_LIST,
IGNORE_FREE_SPACE>(
space, p, &updating_visitor);
}
break;
default:
UNREACHABLE();
@ -4145,10 +4170,15 @@ void MarkCompactCollector::SweepSpace(PagedSpace* space, SweeperType sweeper) {
PrintF("Sweeping 0x%" V8PRIxPTR " precisely.\n",
reinterpret_cast<intptr_t>(p));
}
if (space->identity() == CODE_SPACE) {
SweepPrecisely<SWEEP_ONLY, REBUILD_SKIP_LIST>(space, p, NULL);
if (space->identity() == CODE_SPACE && FLAG_zap_code_space) {
SweepPrecisely<SWEEP_ONLY, REBUILD_SKIP_LIST, ZAP_FREE_SPACE>(
space, p, NULL);
} else if (space->identity() == CODE_SPACE) {
SweepPrecisely<SWEEP_ONLY, REBUILD_SKIP_LIST, IGNORE_FREE_SPACE>(
space, p, NULL);
} else {
SweepPrecisely<SWEEP_ONLY, IGNORE_SKIP_LIST>(space, p, NULL);
SweepPrecisely<SWEEP_ONLY, IGNORE_SKIP_LIST, IGNORE_FREE_SPACE>(
space, p, NULL);
}
pages_swept++;
break;