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Attempt to fix observed AV in mark_through_cards_for_segments #60617

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614fd14
Attempt to fix observed AV in mark_through_cards_for_segments, add in…
PeterSolMS Oct 19, 2021
cb4abcb
Address code review feedback:
PeterSolMS Oct 20, 2021
a404a9f
Save multiple copies of the pinned queue - before and after compact, …
PeterSolMS Oct 21, 2021
96399f1
Disable regions for this experiment.
PeterSolMS Oct 22, 2021
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80 changes: 72 additions & 8 deletions src/coreclr/gc/gc.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2471,6 +2471,10 @@ size_t gc_heap::mark_stack_array_length = 0;

mark* gc_heap::mark_stack_array = 0;

uint32_t gc_heap::saved_pinned_queue_index = 0;

saved_pinned_queue gc_heap::saved_pinned_queues[MAX_SAVED_PINNED_QUEUES];

#if defined (_DEBUG) && defined (VERIFY_HEAP)
BOOL gc_heap::verify_pinned_queue_p = FALSE;
#endif //_DEBUG && VERIFY_HEAP
Expand Down Expand Up @@ -2711,7 +2715,7 @@ alloc_list gc_heap::poh_alloc_list [NUM_POH_ALIST-1];
#ifdef DOUBLY_LINKED_FL
// size we removed with no undo; only for recording purpose
size_t gc_heap::gen2_removed_no_undo = 0;
size_t gc_heap::saved_pinned_plug_index = 0;
size_t gc_heap::saved_pinned_plug_index = INVALID_SAVED_PINNED_PLUG_INDEX;
#endif //DOUBLY_LINKED_FL

#ifdef FEATURE_EVENT_TRACE
Expand Down Expand Up @@ -7808,6 +7812,7 @@ void gc_heap::make_mark_stack (mark* arr)
#ifdef MH_SC_MARK
mark_stack_busy() = 0;
#endif //MH_SC_MARK
saved_pinned_queue_index = 0;
}

#ifdef BACKGROUND_GC
Expand Down Expand Up @@ -14138,7 +14143,20 @@ void gc_heap::adjust_limit (uint8_t* start, size_t limit_size, generation* gen)
uint8_t* old_loc = generation_last_free_list_allocated (gen);

// check if old_loc happens to be in a saved plug_and_gap with a pinned plug after it
uint8_t* saved_plug_and_gap = pinned_plug (pinned_plug_of (saved_pinned_plug_index)) - sizeof(plug_and_gap);
uint8_t* saved_plug_and_gap = nullptr;
if (saved_pinned_plug_index != INVALID_SAVED_PINNED_PLUG_INDEX)
{
saved_plug_and_gap = pinned_plug (pinned_plug_of (saved_pinned_plug_index)) - sizeof(plug_and_gap);

dprintf (5555, ("[h%d] sppi: %Id mtos: %Id old_loc: %Ix pp: %Ix(%Id) offs: %Id",
heap_number,
saved_pinned_plug_index,
mark_stack_tos,
old_loc,
pinned_plug (pinned_plug_of (saved_pinned_plug_index)),
pinned_len (pinned_plug_of (saved_pinned_plug_index)),
old_loc - saved_plug_and_gap));
}
size_t offset = old_loc - saved_plug_and_gap;
if (offset < sizeof(gap_reloc_pair))
{
Expand All @@ -14157,7 +14175,7 @@ void gc_heap::adjust_limit (uint8_t* start, size_t limit_size, generation* gen)
set_free_obj_in_compact_bit (old_loc);
}

dprintf (3333, ("[h%d] ac: %Ix->%Ix((%Id < %Id), Pset %Ix s->%Id", heap_number,
dprintf (5555, ("[h%d] ac: %Ix->%Ix((%Id < %Id), Pset %Ix s->%Id", heap_number,
generation_allocation_context_start_region (gen), generation_allocation_pointer (gen),
allocated_size, min_free_item_no_prev, filler_free_obj_size_location, filler_free_obj_size));
}
Expand Down Expand Up @@ -27783,7 +27801,7 @@ void gc_heap::plan_phase (int condemned_gen_number)

#ifdef DOUBLY_LINKED_FL
gen2_removed_no_undo = 0;
saved_pinned_plug_index = 0;
saved_pinned_plug_index = INVALID_SAVED_PINNED_PLUG_INDEX;
#endif //DOUBLY_LINKED_FL

while (1)
Expand Down Expand Up @@ -32077,6 +32095,43 @@ size_t gc_heap::recover_saved_pinned_info()
return total_recovered_sweep_size;
}

void saved_pinned_queue::save(gc_phase phase, size_t gc_index, size_t tos, size_t length, mark* array)
{
if (mark_stack_array_length < length)
{
if (mark_stack_array != nullptr)
{
delete[] mark_stack_array;
mark_stack_array = nullptr;
}
mark_stack_array = new (nothrow) mark[length];
if (mark_stack_array == nullptr)
{
mark_stack_array_length = 0;
mark_stack_tos = 0;
return;
}
mark_stack_array_length = length;
}
assert (mark_stack_array_length >= length);
memcpy (mark_stack_array, array, sizeof(mark_stack_array[0])*tos);
mark_stack_tos = tos;
saved_gc_index = gc_index;
saved_phase = phase;
}

void gc_heap::save_pinned_queue(saved_pinned_queue::gc_phase phase)
{
saved_pinned_queues[saved_pinned_queue_index].save(
phase,
settings.gc_index,
mark_stack_tos,
mark_stack_array_length,
mark_stack_array);

saved_pinned_queue_index = (saved_pinned_queue_index + 1) % MAX_SAVED_PINNED_QUEUES;
}

void gc_heap::compact_phase (int condemned_gen_number,
uint8_t* first_condemned_address,
BOOL clear_cards)
Expand Down Expand Up @@ -32112,6 +32167,10 @@ void gc_heap::compact_phase (int condemned_gen_number,
#endif //FEATURE_LOH_COMPACTION

reset_pinned_queue_bos();
if (condemned_gen_number == 1)
{
save_pinned_queue(saved_pinned_queue::start_compact);
}
update_oldest_pinned_plug();
BOOL reused_seg = expand_reused_seg_p();
if (reused_seg)
Expand Down Expand Up @@ -32219,6 +32278,11 @@ void gc_heap::compact_phase (int condemned_gen_number,

recover_saved_pinned_info();

if (condemned_gen_number == 1)
{
save_pinned_queue(saved_pinned_queue::end_compact);
}

concurrent_print_time_delta ("compact end");

dprintf (2, (ThreadStressLog::gcEndCompactMsg(), heap_number));
Expand Down Expand Up @@ -44287,15 +44351,15 @@ void gc_heap::do_pre_gc()
#ifdef TRACE_GC
size_t total_allocated_since_last_gc = get_total_allocated_since_last_gc();
#ifdef BACKGROUND_GC
dprintf (1, (ThreadStressLog::gcDetailedStartMsg(),
dprintf (5555, (ThreadStressLog::gcDetailedStartMsg(),
VolatileLoad(&settings.gc_index),
dd_collection_count (hp->dynamic_data_of (0)),
settings.condemned_generation,
total_allocated_since_last_gc,
(settings.concurrent ? "BGC" : (gc_heap::background_running_p() ? "FGC" : "NGC")),
settings.b_state));
#else
dprintf (1, ("*GC* %d(gen0:%d)(%d)(alloc: %Id)",
dprintf (5555, ("*GC* %d(gen0:%d)(%d)(alloc: %Id)",
VolatileLoad(&settings.gc_index),
dd_collection_count(hp->dynamic_data_of(0)),
settings.condemned_generation,
Expand All @@ -44306,7 +44370,7 @@ void gc_heap::do_pre_gc()
{
size_t total_heap_committed = get_total_committed_size();
size_t total_heap_committed_recorded = current_total_committed - current_total_committed_bookkeeping;
dprintf (1, ("(%d)GC commit BEG #%Id: %Id (recorded: %Id = %Id-%Id)",
dprintf (5555, ("(%d)GC commit BEG #%Id: %Id (recorded: %Id = %Id-%Id)",
settings.condemned_generation,
(size_t)settings.gc_index, total_heap_committed, total_heap_committed_recorded,
current_total_committed, current_total_committed_bookkeeping));
Expand Down Expand Up @@ -44706,7 +44770,7 @@ void gc_heap::do_post_gc()
}
#endif //BGC_SERVO_TUNING

dprintf (1, (ThreadStressLog::gcDetailedEndMsg(),
dprintf (5555, (ThreadStressLog::gcDetailedEndMsg(),
VolatileLoad(&settings.gc_index),
dd_collection_count(hp->dynamic_data_of(0)),
(size_t)(GetHighPrecisionTimeStamp() / 1000),
Expand Down
49 changes: 46 additions & 3 deletions src/coreclr/gc/gcpriv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,7 @@ inline void FATAL_GC_ERROR()
// Server GC we will balance regions between heaps.
// For now enable regions by default for only StandAlone GC builds
#if defined (HOST_64BIT) && defined (BUILD_AS_STANDALONE)
#define USE_REGIONS
//#define USE_REGIONS
#endif //HOST_64BIT && BUILD_AS_STANDALONE

#ifdef USE_REGIONS
Expand Down Expand Up @@ -137,7 +137,7 @@ inline void FATAL_GC_ERROR()
#define MAX_LONGPATH 1024
#endif // MAX_LONGPATH

//#define TRACE_GC
#define TRACE_GC
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@mangod9 mangod9 Oct 19, 2021

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guess this needs to be undone?

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@Maoni0 Maoni0 Oct 19, 2021

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right, this is only for the private build... Peter wanted to log these particular dprintfs for instrumentation in the stress log so we can get them in the dump file.

//#define SIMPLE_DPRINTF

//#define JOIN_STATS //amount of time spent in the join
Expand Down Expand Up @@ -261,7 +261,7 @@ void GCLog (const char *fmt, ... );
// wanting to inspect GC logs on unmodified builds, we can use this define here
// to do so.
//#define dprintf(l, x)
#define dprintf(l,x) STRESS_LOG_VA(l,x);
#define dprintf(l,x) {if (l == 5555) {STRESS_LOG_VA(l,x);}}

#endif //SIMPLE_DPRINTF

Expand Down Expand Up @@ -1200,6 +1200,37 @@ enum bookkeeping_element
total_bookkeeping_elements
};

class saved_pinned_queue
{
public:
enum gc_phase
{
invalid,
start_compact,
end_compact,
};

private:
size_t saved_gc_index;
gc_phase saved_phase;
size_t mark_stack_tos;
size_t mark_stack_array_length;
mark* mark_stack_array;

public:

saved_pinned_queue() :
saved_gc_index(0),
saved_phase(invalid),
mark_stack_tos(0),
mark_stack_array_length(0),
mark_stack_array(nullptr)
{
}

void save(gc_phase phase, size_t gc_index, size_t tos, size_t length, mark* array);
};

//class definition of the internal class
class gc_heap
{
Expand Down Expand Up @@ -2310,6 +2341,8 @@ class gc_heap
PER_HEAP
void reset_pinned_queue_bos();
PER_HEAP
void save_pinned_queue(saved_pinned_queue::gc_phase phase);
PER_HEAP
void set_allocator_next_pin (generation* gen);
PER_HEAP
void enque_pinned_plug (generation* gen, uint8_t* plug, size_t len);
Expand Down Expand Up @@ -4070,6 +4103,14 @@ class gc_heap
PER_HEAP
mark* mark_stack_array;

#define MAX_SAVED_PINNED_QUEUES 8

PER_HEAP
uint32_t saved_pinned_queue_index;

PER_HEAP
saved_pinned_queue saved_pinned_queues[MAX_SAVED_PINNED_QUEUES];

#if defined (_DEBUG) && defined (VERIFY_HEAP)
PER_HEAP
BOOL verify_pinned_queue_p;
Expand Down Expand Up @@ -4528,6 +4569,8 @@ class gc_heap
PER_HEAP
size_t gen2_removed_no_undo;

#define INVALID_SAVED_PINNED_PLUG_INDEX (~0)

PER_HEAP
size_t saved_pinned_plug_index;
#endif //DOUBLY_LINKED_FL
Expand Down