--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp Mon Apr 28 09:31:25 2014 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp Wed Apr 30 14:43:00 2014 -0700
@@ -1282,6 +1282,7 @@
Universe::verify(VerifyOption_G1UsePrevMarking,
" VerifyDuringGC:(before)");
}
+ g1h->check_bitmaps("Remark Start");
G1CollectorPolicy* g1p = g1h->g1_policy();
g1p->record_concurrent_mark_remark_start();
@@ -1330,6 +1331,7 @@
Universe::verify(VerifyOption_G1UseNextMarking,
" VerifyDuringGC:(after)");
}
+ g1h->check_bitmaps("Remark End");
assert(!restart_for_overflow(), "sanity");
// Completely reset the marking state since marking completed
set_non_marking_state();
@@ -1979,6 +1981,7 @@
Universe::verify(VerifyOption_G1UsePrevMarking,
" VerifyDuringGC:(before)");
}
+ g1h->check_bitmaps("Cleanup Start");
G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy();
g1p->record_concurrent_mark_cleanup_start();
@@ -2133,6 +2136,7 @@
Universe::verify(VerifyOption_G1UsePrevMarking,
" VerifyDuringGC:(after)");
}
+ g1h->check_bitmaps("Cleanup End");
g1h->verify_region_sets_optional();
g1h->trace_heap_after_concurrent_cycle();
@@ -3224,6 +3228,11 @@
void ConcurrentMark::abort() {
// Clear all marks to force marking thread to do nothing
_nextMarkBitMap->clearAll();
+
+ // Note we cannot clear the previous marking bitmap here
+ // since VerifyDuringGC verifies the objects marked during
+ // a full GC against the previous bitmap.
+
// Clear the liveness counting data
clear_all_count_data();
// Empty mark stack
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Mon Apr 28 09:31:25 2014 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Wed Apr 30 14:43:00 2014 -0700
@@ -768,6 +768,7 @@
// match new_top.
assert(hr == NULL ||
(hr->end() == new_end && hr->top() == new_top), "sanity");
+ check_bitmaps("Humongous Region Allocation", first_hr);
assert(first_hr->used() == word_size * HeapWordSize, "invariant");
_summary_bytes_used += first_hr->used();
@@ -1326,6 +1327,7 @@
verify_before_gc();
+ check_bitmaps("Full GC Start");
pre_full_gc_dump(gc_timer);
COMPILER2_PRESENT(DerivedPointerTable::clear());
@@ -1499,6 +1501,18 @@
verify_after_gc();
+ // Clear the previous marking bitmap, if needed for bitmap verification.
+ // Note we cannot do this when we clear the next marking bitmap in
+ // ConcurrentMark::abort() above since VerifyDuringGC verifies the
+ // objects marked during a full GC against the previous bitmap.
+ // But we need to clear it before calling check_bitmaps below since
+ // the full GC has compacted objects and updated TAMS but not updated
+ // the prev bitmap.
+ if (G1VerifyBitmaps) {
+ ((CMBitMap*) concurrent_mark()->prevMarkBitMap())->clearAll();
+ }
+ check_bitmaps("Full GC End");
+
// Start a new incremental collection set for the next pause
assert(g1_policy()->collection_set() == NULL, "must be");
g1_policy()->start_incremental_cset_building();
@@ -3978,6 +3992,7 @@
increment_gc_time_stamp();
verify_before_gc();
+ check_bitmaps("GC Start");
COMPILER2_PRESENT(DerivedPointerTable::clear());
@@ -4223,6 +4238,7 @@
increment_gc_time_stamp();
verify_after_gc();
+ check_bitmaps("GC End");
assert(!ref_processor_stw()->discovery_enabled(), "Postcondition");
ref_processor_stw()->verify_no_references_recorded();
@@ -5945,6 +5961,11 @@
assert(!hr->is_empty(), "the region should not be empty");
assert(free_list != NULL, "pre-condition");
+ if (G1VerifyBitmaps) {
+ MemRegion mr(hr->bottom(), hr->end());
+ concurrent_mark()->clearRangePrevBitmap(mr);
+ }
+
// Clear the card counts for this region.
// Note: we only need to do this if the region is not young
// (since we don't refine cards in young regions).
@@ -6079,7 +6100,87 @@
void G1CollectedHeap::verify_dirty_young_regions() {
verify_dirty_young_list(_young_list->first_region());
}
-#endif
+
+bool G1CollectedHeap::verify_no_bits_over_tams(const char* bitmap_name, CMBitMapRO* bitmap,
+ HeapWord* tams, HeapWord* end) {
+ guarantee(tams <= end,
+ err_msg("tams: "PTR_FORMAT" end: "PTR_FORMAT, tams, end));
+ HeapWord* result = bitmap->getNextMarkedWordAddress(tams, end);
+ if (result < end) {
+ gclog_or_tty->cr();
+ gclog_or_tty->print_cr("## wrong marked address on %s bitmap: "PTR_FORMAT,
+ bitmap_name, result);
+ gclog_or_tty->print_cr("## %s tams: "PTR_FORMAT" end: "PTR_FORMAT,
+ bitmap_name, tams, end);
+ return false;
+ }
+ return true;
+}
+
+bool G1CollectedHeap::verify_bitmaps(const char* caller, HeapRegion* hr) {
+ CMBitMapRO* prev_bitmap = concurrent_mark()->prevMarkBitMap();
+ CMBitMapRO* next_bitmap = (CMBitMapRO*) concurrent_mark()->nextMarkBitMap();
+
+ HeapWord* bottom = hr->bottom();
+ HeapWord* ptams = hr->prev_top_at_mark_start();
+ HeapWord* ntams = hr->next_top_at_mark_start();
+ HeapWord* end = hr->end();
+
+ bool res_p = verify_no_bits_over_tams("prev", prev_bitmap, ptams, end);
+
+ bool res_n = true;
+ // We reset mark_in_progress() before we reset _cmThread->in_progress() and in this window
+ // we do the clearing of the next bitmap concurrently. Thus, we can not verify the bitmap
+ // if we happen to be in that state.
+ if (mark_in_progress() || !_cmThread->in_progress()) {
+ res_n = verify_no_bits_over_tams("next", next_bitmap, ntams, end);
+ }
+ if (!res_p || !res_n) {
+ gclog_or_tty->print_cr("#### Bitmap verification failed for "HR_FORMAT,
+ HR_FORMAT_PARAMS(hr));
+ gclog_or_tty->print_cr("#### Caller: %s", caller);
+ return false;
+ }
+ return true;
+}
+
+void G1CollectedHeap::check_bitmaps(const char* caller, HeapRegion* hr) {
+ if (!G1VerifyBitmaps) return;
+
+ guarantee(verify_bitmaps(caller, hr), "bitmap verification");
+}
+
+class G1VerifyBitmapClosure : public HeapRegionClosure {
+private:
+ const char* _caller;
+ G1CollectedHeap* _g1h;
+ bool _failures;
+
+public:
+ G1VerifyBitmapClosure(const char* caller, G1CollectedHeap* g1h) :
+ _caller(caller), _g1h(g1h), _failures(false) { }
+
+ bool failures() { return _failures; }
+
+ virtual bool doHeapRegion(HeapRegion* hr) {
+ if (hr->continuesHumongous()) return false;
+
+ bool result = _g1h->verify_bitmaps(_caller, hr);
+ if (!result) {
+ _failures = true;
+ }
+ return false;
+ }
+};
+
+void G1CollectedHeap::check_bitmaps(const char* caller) {
+ if (!G1VerifyBitmaps) return;
+
+ G1VerifyBitmapClosure cl(caller, this);
+ heap_region_iterate(&cl);
+ guarantee(!cl.failures(), "bitmap verification");
+}
+#endif // PRODUCT
void G1CollectedHeap::cleanUpCardTable() {
G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
@@ -6464,6 +6565,7 @@
if (new_alloc_region != NULL) {
set_region_short_lived_locked(new_alloc_region);
_hr_printer.alloc(new_alloc_region, G1HRPrinter::Eden, young_list_full);
+ check_bitmaps("Mutator Region Allocation", new_alloc_region);
return new_alloc_region;
}
}
@@ -6530,8 +6632,10 @@
if (survivor) {
new_alloc_region->set_survivor();
_hr_printer.alloc(new_alloc_region, G1HRPrinter::Survivor);
+ check_bitmaps("Survivor Region Allocation", new_alloc_region);
} else {
_hr_printer.alloc(new_alloc_region, G1HRPrinter::Old);
+ check_bitmaps("Old Region Allocation", new_alloc_region);
}
bool during_im = g1_policy()->during_initial_mark_pause();
new_alloc_region->note_start_of_copying(during_im);
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Mon Apr 28 09:31:25 2014 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Wed Apr 30 14:43:00 2014 -0700
@@ -1186,6 +1186,30 @@
void verify_dirty_young_list(HeapRegion* head) PRODUCT_RETURN;
void verify_dirty_young_regions() PRODUCT_RETURN;
+#ifndef PRODUCT
+ // Make sure that the given bitmap has no marked objects in the
+ // range [from,limit). If it does, print an error message and return
+ // false. Otherwise, just return true. bitmap_name should be "prev"
+ // or "next".
+ bool verify_no_bits_over_tams(const char* bitmap_name, CMBitMapRO* bitmap,
+ HeapWord* from, HeapWord* limit);
+
+ // Verify that the prev / next bitmap range [tams,end) for the given
+ // region has no marks. Return true if all is well, false if errors
+ // are detected.
+ bool verify_bitmaps(const char* caller, HeapRegion* hr);
+#endif // PRODUCT
+
+ // If G1VerifyBitmaps is set, verify that the marking bitmaps for
+ // the given region do not have any spurious marks. If errors are
+ // detected, print appropriate error messages and crash.
+ void check_bitmaps(const char* caller, HeapRegion* hr) PRODUCT_RETURN;
+
+ // If G1VerifyBitmaps is set, verify that the marking bitmaps do not
+ // have any spurious marks. If errors are detected, print
+ // appropriate error messages and crash.
+ void check_bitmaps(const char* caller) PRODUCT_RETURN;
+
// verify_region_sets() performs verification over the region
// lists. It will be compiled in the product code to be used when
// necessary (i.e., during heap verification).
--- a/hotspot/src/share/vm/gc_implementation/g1/g1EvacFailure.hpp Mon Apr 28 09:31:25 2014 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1EvacFailure.hpp Wed Apr 30 14:43:00 2014 -0700
@@ -191,6 +191,7 @@
hr->note_self_forwarding_removal_start(during_initial_mark,
during_conc_mark);
+ _g1h->check_bitmaps("Self-Forwarding Ptr Removal", hr);
// In the common case (i.e. when there is no evacuation
// failure) we make sure that the following is done when
--- a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Mon Apr 28 09:31:25 2014 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Wed Apr 30 14:43:00 2014 -0700
@@ -325,11 +325,14 @@
"evacuation pauses") \
\
diagnostic(bool, G1VerifyRSetsDuringFullGC, false, \
- "If true, perform verification of each heap region's " \
- "remembered set when verifying the heap during a full GC.") \
+ "If true, perform verification of each heap region's " \
+ "remembered set when verifying the heap during a full GC.") \
\
diagnostic(bool, G1VerifyHeapRegionCodeRoots, false, \
- "Verify the code root lists attached to each heap region.")
+ "Verify the code root lists attached to each heap region.") \
+ \
+ develop(bool, G1VerifyBitmaps, false, \
+ "Verifies the consistency of the marking bitmaps")
G1_FLAGS(DECLARE_DEVELOPER_FLAG, DECLARE_PD_DEVELOPER_FLAG, DECLARE_PRODUCT_FLAG, DECLARE_PD_PRODUCT_FLAG, DECLARE_DIAGNOSTIC_FLAG, DECLARE_EXPERIMENTAL_FLAG, DECLARE_NOTPRODUCT_FLAG, DECLARE_MANAGEABLE_FLAG, DECLARE_PRODUCT_RW_FLAG)