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alloc.c
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alloc.c
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/*
* Copyright (c) 1988-1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved.
* Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
* Copyright (c) 1999-2011 Hewlett-Packard Development Company, L.P.
* Copyright (c) 2008-2022 Ivan Maidanski
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
#include "private/gc_priv.h"
/*
* Separate free lists are maintained for different sized objects
* up to MAXOBJBYTES.
* The call GC_allocobj(lg, k) ensures that the free list for
* kind k objects of size lg granules to a non-empty
* free list. It returns a pointer to the first entry on the free list.
* In a single-threaded world, GC_allocobj may be called to allocate
* an object of small size lb (and NORMAL kind) as follows
* (GC_generic_malloc_inner is a wrapper over GC_allocobj which also
* fills in GC_size_map if needed):
*
* lg = GC_size_map[lb];
* op = GC_objfreelist[lg];
* if (NULL == op) {
* op = GC_generic_malloc_inner(lb, NORMAL, 0);
* } else {
* GC_objfreelist[lg] = obj_link(op);
* GC_bytes_allocd += GRANULES_TO_BYTES((word)lg);
* }
*
* Note that this is very fast if the free list is non-empty; it should
* only involve the execution of 4 or 5 simple instructions.
* All composite objects on freelists are cleared, except for
* their first "pointer-sized" word.
*/
/*
* The allocator uses GC_allochblk to allocate large chunks of objects.
* These chunks all start on addresses which are multiples of
* HBLKSZ. Each allocated chunk has an associated header,
* which can be located quickly based on the address of the chunk.
* (See headers.c for details.)
* This makes it possible to check quickly whether an
* arbitrary address corresponds to an object administered by the
* allocator.
*/
word GC_non_gc_bytes = 0; /* Number of bytes not intended to be collected */
word GC_gc_no = 0;
#ifndef NO_CLOCK
static unsigned long full_gc_total_time = 0; /* in ms, may wrap */
static unsigned long stopped_mark_total_time = 0;
static unsigned32 full_gc_total_ns_frac = 0; /* fraction of 1 ms */
static unsigned32 stopped_mark_total_ns_frac = 0;
static GC_bool measure_performance = FALSE;
/* Do performance measurements if set to true (e.g., */
/* accumulation of the total time of full collections). */
GC_API void GC_CALL GC_start_performance_measurement(void)
{
measure_performance = TRUE;
}
GC_API unsigned long GC_CALL GC_get_full_gc_total_time(void)
{
return full_gc_total_time;
}
GC_API unsigned long GC_CALL GC_get_stopped_mark_total_time(void)
{
return stopped_mark_total_time;
}
#endif /* !NO_CLOCK */
#ifndef GC_DISABLE_INCREMENTAL
GC_INNER GC_bool GC_incremental = FALSE; /* By default, stop the world. */
STATIC GC_bool GC_should_start_incremental_collection = FALSE;
#endif
GC_API int GC_CALL GC_is_incremental_mode(void)
{
return (int)GC_incremental;
}
#ifdef THREADS
int GC_parallel = FALSE; /* By default, parallel GC is off. */
#endif
#if defined(GC_FULL_FREQ) && !defined(CPPCHECK)
int GC_full_freq = GC_FULL_FREQ;
#else
int GC_full_freq = 19; /* Every 20th collection is a full */
/* collection, whether we need it */
/* or not. */
#endif
STATIC GC_bool GC_need_full_gc = FALSE;
/* Need full GC due to heap growth. */
#ifdef THREAD_LOCAL_ALLOC
GC_INNER GC_bool GC_world_stopped = FALSE;
#endif
STATIC GC_bool GC_disable_automatic_collection = FALSE;
GC_API void GC_CALL GC_set_disable_automatic_collection(int value)
{
LOCK();
GC_disable_automatic_collection = (GC_bool)value;
UNLOCK();
}
GC_API int GC_CALL GC_get_disable_automatic_collection(void)
{
int value;
READER_LOCK();
value = (int)GC_disable_automatic_collection;
READER_UNLOCK();
return value;
}
STATIC word GC_used_heap_size_after_full = 0;
/* Version macros are now defined in gc_version.h, which is included by */
/* gc.h, which is included by gc_priv.h. */
#ifndef GC_NO_VERSION_VAR
EXTERN_C_BEGIN
extern const GC_VERSION_VAL_T GC_version;
EXTERN_C_END
const GC_VERSION_VAL_T GC_version =
((GC_VERSION_VAL_T)GC_VERSION_MAJOR << 16)
| (GC_VERSION_MINOR << 8) | GC_VERSION_MICRO;
#endif
GC_API GC_VERSION_VAL_T GC_CALL GC_get_version(void)
{
return ((GC_VERSION_VAL_T)GC_VERSION_MAJOR << 16)
| (GC_VERSION_MINOR << 8) | GC_VERSION_MICRO;
}
GC_API int GC_CALL GC_get_dont_add_byte_at_end(void)
{
# ifdef DONT_ADD_BYTE_AT_END
return 1;
# else
return 0; /* meaningful only if GC_all_interior_pointers */
# endif
}
/* some more variables */
#ifdef GC_DONT_EXPAND
int GC_dont_expand = TRUE;
#else
int GC_dont_expand = FALSE;
#endif
#if defined(GC_FREE_SPACE_DIVISOR) && !defined(CPPCHECK)
word GC_free_space_divisor = GC_FREE_SPACE_DIVISOR; /* must be > 0 */
#else
word GC_free_space_divisor = 3;
#endif
GC_INNER int GC_CALLBACK GC_never_stop_func(void)
{
return FALSE;
}
#if defined(GC_TIME_LIMIT) && !defined(CPPCHECK)
unsigned long GC_time_limit = GC_TIME_LIMIT;
/* We try to keep pause times from exceeding */
/* this by much. In milliseconds. */
#elif defined(PARALLEL_MARK)
unsigned long GC_time_limit = GC_TIME_UNLIMITED;
/* The parallel marker cannot be interrupted for */
/* now, so the time limit is absent by default. */
#else
unsigned long GC_time_limit = 15;
#endif
#ifndef NO_CLOCK
STATIC unsigned long GC_time_lim_nsec = 0;
/* The nanoseconds add-on to GC_time_limit */
/* value. Not updated by GC_set_time_limit(). */
/* Ignored if the value of GC_time_limit is */
/* GC_TIME_UNLIMITED. */
# define TV_NSEC_LIMIT (1000UL * 1000) /* amount of nanoseconds in 1 ms */
GC_API void GC_CALL GC_set_time_limit_tv(struct GC_timeval_s tv)
{
GC_ASSERT(tv.tv_ms <= GC_TIME_UNLIMITED);
GC_ASSERT(tv.tv_nsec < TV_NSEC_LIMIT);
GC_time_limit = tv.tv_ms;
GC_time_lim_nsec = tv.tv_nsec;
}
GC_API struct GC_timeval_s GC_CALL GC_get_time_limit_tv(void)
{
struct GC_timeval_s tv;
tv.tv_ms = GC_time_limit;
tv.tv_nsec = GC_time_lim_nsec;
return tv;
}
STATIC CLOCK_TYPE GC_start_time = CLOCK_TYPE_INITIALIZER;
/* Time at which we stopped world. */
/* used only in GC_timeout_stop_func. */
#endif /* !NO_CLOCK */
STATIC int GC_n_attempts = 0; /* Number of attempts at finishing */
/* collection within GC_time_limit. */
STATIC GC_stop_func GC_default_stop_func = GC_never_stop_func;
/* Accessed holding the allocator lock. */
GC_API void GC_CALL GC_set_stop_func(GC_stop_func stop_func)
{
GC_ASSERT(NONNULL_ARG_NOT_NULL(stop_func));
LOCK();
GC_default_stop_func = stop_func;
UNLOCK();
}
GC_API GC_stop_func GC_CALL GC_get_stop_func(void)
{
GC_stop_func stop_func;
READER_LOCK();
stop_func = GC_default_stop_func;
READER_UNLOCK();
return stop_func;
}
#if defined(GC_DISABLE_INCREMENTAL) || defined(NO_CLOCK)
# define GC_timeout_stop_func GC_default_stop_func
#else
STATIC int GC_CALLBACK GC_timeout_stop_func(void)
{
CLOCK_TYPE current_time;
static unsigned count = 0;
unsigned long time_diff, nsec_diff;
GC_ASSERT(I_HOLD_LOCK());
if (GC_default_stop_func())
return TRUE;
if (GC_time_limit == GC_TIME_UNLIMITED || (count++ & 3) != 0)
return FALSE;
GET_TIME(current_time);
time_diff = MS_TIME_DIFF(current_time, GC_start_time);
nsec_diff = NS_FRAC_TIME_DIFF(current_time, GC_start_time);
# if defined(CPPCHECK)
GC_noop1_ptr(&nsec_diff);
# endif
if (time_diff >= GC_time_limit
&& (time_diff > GC_time_limit || nsec_diff >= GC_time_lim_nsec)) {
GC_COND_LOG_PRINTF("Abandoning stopped marking after %lu ms %lu ns"
" (attempt %d)\n",
time_diff, nsec_diff, GC_n_attempts);
return TRUE;
}
return FALSE;
}
#endif /* !GC_DISABLE_INCREMENTAL */
#ifdef THREADS
GC_INNER word GC_total_stacksize = 0; /* updated on every push_all_stacks */
#endif
static size_t min_bytes_allocd_minimum = 1;
/* The lowest value returned by min_bytes_allocd(). */
GC_API void GC_CALL GC_set_min_bytes_allocd(size_t value)
{
GC_ASSERT(value > 0);
min_bytes_allocd_minimum = value;
}
GC_API size_t GC_CALL GC_get_min_bytes_allocd(void)
{
return min_bytes_allocd_minimum;
}
/* Return the minimum number of bytes that must be allocated between */
/* collections to amortize the collection cost. Should be non-zero. */
static word min_bytes_allocd(void)
{
word result;
word stack_size;
word total_root_size; /* includes double stack size, */
/* since the stack is expensive */
/* to scan. */
word scan_size; /* Estimate of memory to be scanned */
/* during normal GC. */
GC_ASSERT(I_HOLD_LOCK());
# ifdef THREADS
if (GC_need_to_lock) {
/* We are multi-threaded... */
stack_size = GC_total_stacksize;
/* For now, we just use the value computed during the latest GC. */
# ifdef DEBUG_THREADS
GC_log_printf("Total stacks size: %lu\n",
(unsigned long)stack_size);
# endif
} else
# endif
/* else*/ {
# ifdef STACK_NOT_SCANNED
stack_size = 0;
# elif defined(STACK_GROWS_UP)
stack_size = (word)(GC_approx_sp() - GC_stackbottom);
# else
stack_size = (word)(GC_stackbottom - GC_approx_sp());
# endif
}
total_root_size = 2 * stack_size + GC_root_size;
scan_size = 2 * GC_composite_in_use + GC_atomic_in_use / 4
+ total_root_size;
result = scan_size / GC_free_space_divisor;
if (GC_incremental) {
result /= 2;
}
return result > min_bytes_allocd_minimum
? result : min_bytes_allocd_minimum;
}
STATIC word GC_non_gc_bytes_at_gc = 0;
/* Number of explicitly managed bytes of storage */
/* at last collection. */
/* Return the number of bytes allocated, adjusted for explicit storage */
/* management, etc. This number is used in deciding when to trigger */
/* collections. */
STATIC word GC_adj_bytes_allocd(void)
{
signed_word result;
signed_word expl_managed = (signed_word)GC_non_gc_bytes
- (signed_word)GC_non_gc_bytes_at_gc;
/* Don't count what was explicitly freed, or newly allocated for */
/* explicit management. Note that deallocating an explicitly */
/* managed object should not alter result, assuming the client */
/* is playing by the rules. */
result = (signed_word)GC_bytes_allocd
+ (signed_word)GC_bytes_dropped
- (signed_word)GC_bytes_freed
+ (signed_word)GC_finalizer_bytes_freed
- expl_managed;
if (result > (signed_word)GC_bytes_allocd) {
result = (signed_word)GC_bytes_allocd;
/* probably client bug or unfortunate scheduling */
}
result += (signed_word)GC_bytes_finalized;
/* We count objects enqueued for finalization as though they */
/* had been reallocated this round. Finalization is user */
/* visible progress. And if we don't count this, we have */
/* stability problems for programs that finalize all objects. */
if (result < (signed_word)(GC_bytes_allocd >> 3)) {
/* Always count at least 1/8 of the allocations. We don't want */
/* to collect too infrequently, since that would inhibit */
/* coalescing of free storage blocks. */
/* This also makes us partially robust against client bugs. */
result = (signed_word)(GC_bytes_allocd >> 3);
}
return (word)result;
}
/* Clear up a few frames worth of garbage left at the top of the stack. */
/* This is used to prevent us from accidentally treating garbage left */
/* on the stack by other parts of the collector as roots. This */
/* differs from the code in misc.c, which actually tries to keep the */
/* stack clear of long-lived, client-generated garbage. */
STATIC void GC_clear_a_few_frames(void)
{
# ifndef CLEAR_STACK_NPTRS
# define CLEAR_STACK_NPTRS 64 /* pointers */
# endif
volatile ptr_t frames[CLEAR_STACK_NPTRS];
BZERO(CAST_AWAY_VOLATILE_PVOID(frames), sizeof(frames));
}
GC_API void GC_CALL GC_start_incremental_collection(void)
{
# ifndef GC_DISABLE_INCREMENTAL
LOCK();
if (GC_incremental) {
GC_should_start_incremental_collection = TRUE;
if (!GC_dont_gc) {
ENTER_GC();
GC_collect_a_little_inner(1);
EXIT_GC();
}
}
UNLOCK();
# endif
}
/* Have we allocated enough to amortize a collection? */
GC_INNER GC_bool GC_should_collect(void)
{
static word last_min_bytes_allocd;
static word last_gc_no;
GC_ASSERT(I_HOLD_LOCK());
if (last_gc_no != GC_gc_no) {
last_min_bytes_allocd = min_bytes_allocd();
last_gc_no = GC_gc_no;
}
# ifndef GC_DISABLE_INCREMENTAL
if (GC_should_start_incremental_collection) {
GC_should_start_incremental_collection = FALSE;
return TRUE;
}
# endif
if (GC_disable_automatic_collection) return FALSE;
if (GC_last_heap_growth_gc_no == GC_gc_no)
return TRUE; /* avoid expanding past limits used by blacklisting */
return GC_adj_bytes_allocd() >= last_min_bytes_allocd;
}
/* STATIC */ GC_start_callback_proc GC_start_call_back = 0;
/* Called at start of full collections. */
/* Not called if 0. Called with the allocator */
/* lock held. Not used by GC itself. */
GC_API void GC_CALL GC_set_start_callback(GC_start_callback_proc fn)
{
LOCK();
GC_start_call_back = fn;
UNLOCK();
}
GC_API GC_start_callback_proc GC_CALL GC_get_start_callback(void)
{
GC_start_callback_proc fn;
READER_LOCK();
fn = GC_start_call_back;
READER_UNLOCK();
return fn;
}
GC_INLINE void GC_notify_full_gc(void)
{
if (GC_start_call_back != 0) {
(*GC_start_call_back)();
}
}
STATIC GC_bool GC_is_full_gc = FALSE;
STATIC GC_bool GC_stopped_mark(GC_stop_func stop_func);
STATIC void GC_finish_collection(void);
/* Initiate a garbage collection if appropriate. Choose judiciously */
/* between partial, full, and stop-world collections. */
STATIC void GC_maybe_gc(void)
{
static int n_partial_gcs = 0;
GC_ASSERT(I_HOLD_LOCK());
ASSERT_CANCEL_DISABLED();
if (!GC_should_collect()) return;
if (!GC_incremental) {
GC_gcollect_inner();
return;
}
GC_ASSERT(!GC_collection_in_progress());
# ifdef PARALLEL_MARK
if (GC_parallel)
GC_wait_for_reclaim();
# endif
if (GC_need_full_gc || n_partial_gcs >= GC_full_freq) {
GC_COND_LOG_PRINTF(
"***>Full mark for collection #%lu after %lu allocd bytes\n",
(unsigned long)GC_gc_no + 1, (unsigned long)GC_bytes_allocd);
GC_promote_black_lists();
(void)GC_reclaim_all((GC_stop_func)0, TRUE);
GC_notify_full_gc();
GC_clear_marks();
n_partial_gcs = 0;
GC_is_full_gc = TRUE;
} else {
n_partial_gcs++;
}
/* Try to mark with the world stopped. If we run out of */
/* time, this turns into an incremental marking. */
# ifndef NO_CLOCK
if (GC_time_limit != GC_TIME_UNLIMITED) GET_TIME(GC_start_time);
# endif
if (GC_stopped_mark(GC_timeout_stop_func)) {
SAVE_CALLERS_TO_LAST_STACK();
GC_finish_collection();
} else if (!GC_is_full_gc) {
/* Count this as the first attempt. */
GC_n_attempts++;
}
}
STATIC GC_on_collection_event_proc GC_on_collection_event = 0;
GC_API void GC_CALL GC_set_on_collection_event(GC_on_collection_event_proc fn)
{
/* fn may be 0 (means no event notifier). */
LOCK();
GC_on_collection_event = fn;
UNLOCK();
}
GC_API GC_on_collection_event_proc GC_CALL GC_get_on_collection_event(void)
{
GC_on_collection_event_proc fn;
READER_LOCK();
fn = GC_on_collection_event;
READER_UNLOCK();
return fn;
}
/* Stop the world garbage collection. If stop_func is not */
/* GC_never_stop_func then abort if stop_func returns TRUE. */
/* Return TRUE if we successfully completed the collection. */
GC_INNER GC_bool GC_try_to_collect_inner(GC_stop_func stop_func)
{
# ifndef NO_CLOCK
CLOCK_TYPE start_time = CLOCK_TYPE_INITIALIZER;
GC_bool start_time_valid;
# endif
ASSERT_CANCEL_DISABLED();
GC_ASSERT(I_HOLD_LOCK());
GC_ASSERT(GC_is_initialized);
if (GC_dont_gc || (*stop_func)()) return FALSE;
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_START);
if (GC_incremental && GC_collection_in_progress()) {
GC_COND_LOG_PRINTF(
"GC_try_to_collect_inner: finishing collection in progress\n");
/* Just finish collection already in progress. */
do {
if ((*stop_func)()) {
/* TODO: Notify GC_EVENT_ABANDON */
return FALSE;
}
ENTER_GC();
GC_collect_a_little_inner(1);
EXIT_GC();
} while (GC_collection_in_progress());
}
GC_notify_full_gc();
# ifndef NO_CLOCK
start_time_valid = FALSE;
if ((GC_print_stats | (int)measure_performance) != 0) {
if (GC_print_stats)
GC_log_printf("Initiating full world-stop collection!\n");
start_time_valid = TRUE;
GET_TIME(start_time);
}
# endif
GC_promote_black_lists();
/* Make sure all blocks have been reclaimed, so sweep routines */
/* don't see cleared mark bits. */
/* If we're guaranteed to finish, then this is unnecessary. */
/* In the find_leak case, we have to finish to guarantee that */
/* previously unmarked objects are not reported as leaks. */
# ifdef PARALLEL_MARK
if (GC_parallel)
GC_wait_for_reclaim();
# endif
if ((GC_find_leak || stop_func != GC_never_stop_func)
&& !GC_reclaim_all(stop_func, FALSE)) {
/* Aborted. So far everything is still consistent. */
/* TODO: Notify GC_EVENT_ABANDON */
return FALSE;
}
GC_invalidate_mark_state(); /* Flush mark stack. */
GC_clear_marks();
SAVE_CALLERS_TO_LAST_STACK();
GC_is_full_gc = TRUE;
if (!GC_stopped_mark(stop_func)) {
if (!GC_incremental) {
/* We're partially done and have no way to complete or use */
/* current work. Reestablish invariants as cheaply as */
/* possible. */
GC_invalidate_mark_state();
GC_unpromote_black_lists();
} /* else we claim the world is already still consistent. We'll */
/* finish incrementally. */
/* TODO: Notify GC_EVENT_ABANDON */
return FALSE;
}
GC_finish_collection();
# ifndef NO_CLOCK
if (start_time_valid) {
CLOCK_TYPE current_time;
unsigned long time_diff, ns_frac_diff;
GET_TIME(current_time);
time_diff = MS_TIME_DIFF(current_time, start_time);
ns_frac_diff = NS_FRAC_TIME_DIFF(current_time, start_time);
if (measure_performance) {
full_gc_total_time += time_diff; /* may wrap */
full_gc_total_ns_frac += (unsigned32)ns_frac_diff;
if (full_gc_total_ns_frac >= (unsigned32)1000000UL) {
/* Overflow of the nanoseconds part. */
full_gc_total_ns_frac -= (unsigned32)1000000UL;
full_gc_total_time++;
}
}
if (GC_print_stats)
GC_log_printf("Complete collection took %lu ms %lu ns\n",
time_diff, ns_frac_diff);
}
# endif
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_END);
return TRUE;
}
/* The number of extra calls to GC_mark_some that we have made. */
STATIC size_t GC_deficit = 0;
/* The default value of GC_rate. */
#ifndef GC_RATE
# define GC_RATE 10
#endif
/* When GC_collect_a_little_inner() performs n_blocks units of garbage */
/* collection work, a unit is intended to touch roughly GC_rate pages. */
/* (But, every once in a while, we do more than that.) This needs to */
/* be a fairly large number with our current incremental GC strategy, */
/* since otherwise we allocate too much during GC, and the cleanup gets */
/* expensive. */
STATIC unsigned GC_rate = GC_RATE;
GC_API void GC_CALL GC_set_rate(int value)
{
GC_ASSERT(value > 0);
GC_rate = (unsigned)value;
}
GC_API int GC_CALL GC_get_rate(void)
{
return (int)GC_rate;
}
/* The default maximum number of prior attempts at world stop marking. */
#ifndef MAX_PRIOR_ATTEMPTS
# define MAX_PRIOR_ATTEMPTS 3
#endif
/* The maximum number of prior attempts at world stop marking. */
/* A value of 1 means that we finish the second time, no matter how */
/* long it takes. Does not count the initial root scan for a full GC. */
static int max_prior_attempts = MAX_PRIOR_ATTEMPTS;
GC_API void GC_CALL GC_set_max_prior_attempts(int value)
{
GC_ASSERT(value >= 0);
max_prior_attempts = value;
}
GC_API int GC_CALL GC_get_max_prior_attempts(void)
{
return max_prior_attempts;
}
GC_INNER void GC_collect_a_little_inner(size_t n_blocks)
{
IF_CANCEL(int cancel_state;)
GC_ASSERT(I_HOLD_LOCK());
GC_ASSERT(GC_is_initialized);
DISABLE_CANCEL(cancel_state);
if (GC_incremental && GC_collection_in_progress()) {
size_t i;
size_t max_deficit = GC_rate * n_blocks;
# ifdef PARALLEL_MARK
if (GC_time_limit != GC_TIME_UNLIMITED)
GC_parallel_mark_disabled = TRUE;
# endif
for (i = GC_deficit; i < max_deficit; i++) {
if (GC_mark_some(NULL))
break;
}
# ifdef PARALLEL_MARK
GC_parallel_mark_disabled = FALSE;
# endif
if (i < max_deficit && !GC_dont_gc) {
GC_ASSERT(!GC_collection_in_progress());
/* Need to follow up with a full collection. */
SAVE_CALLERS_TO_LAST_STACK();
# ifdef PARALLEL_MARK
if (GC_parallel)
GC_wait_for_reclaim();
# endif
# ifndef NO_CLOCK
if (GC_time_limit != GC_TIME_UNLIMITED
&& GC_n_attempts < max_prior_attempts)
GET_TIME(GC_start_time);
# endif
if (GC_stopped_mark(GC_n_attempts < max_prior_attempts ?
GC_timeout_stop_func : GC_never_stop_func)) {
GC_finish_collection();
} else {
GC_n_attempts++;
}
}
if (GC_deficit > 0) {
GC_deficit = GC_deficit > max_deficit
? GC_deficit - max_deficit : 0;
}
} else if (!GC_dont_gc) {
GC_maybe_gc();
}
RESTORE_CANCEL(cancel_state);
}
GC_INNER void (*GC_check_heap)(void) = 0;
GC_INNER void (*GC_print_all_smashed)(void) = 0;
GC_API int GC_CALL GC_collect_a_little(void)
{
int result;
if (!EXPECT(GC_is_initialized, TRUE)) GC_init();
LOCK();
ENTER_GC();
/* Note: if the collection is in progress, this may do marking (not */
/* stopping the world) even in case of disabled GC. */
GC_collect_a_little_inner(1);
EXIT_GC();
result = (int)GC_collection_in_progress();
UNLOCK();
if (!result && GC_debugging_started) GC_print_all_smashed();
return result;
}
#ifdef THREADS
GC_API void GC_CALL GC_stop_world_external(void)
{
GC_ASSERT(GC_is_initialized);
LOCK();
# ifdef THREAD_LOCAL_ALLOC
GC_ASSERT(!GC_world_stopped);
# endif
STOP_WORLD();
# ifdef THREAD_LOCAL_ALLOC
GC_world_stopped = TRUE;
# endif
}
GC_API void GC_CALL GC_start_world_external(void)
{
# ifdef THREAD_LOCAL_ALLOC
GC_ASSERT(GC_world_stopped);
GC_world_stopped = FALSE;
# else
GC_ASSERT(GC_is_initialized);
# endif
START_WORLD();
UNLOCK();
}
#endif /* THREADS */
#ifndef NO_CLOCK
/* Variables for world-stop average delay time statistic computation. */
/* "divisor" is incremented every world-stop and halved when reached */
/* its maximum (or upon "total_time" overflow). */
static unsigned world_stopped_total_time = 0;
static unsigned world_stopped_total_divisor = 0;
# ifndef MAX_TOTAL_TIME_DIVISOR
/* We shall not use big values here (so "outdated" delay time */
/* values would have less impact on "average" delay time value than */
/* newer ones). */
# define MAX_TOTAL_TIME_DIVISOR 1000
# endif
#endif /* !NO_CLOCK */
#ifdef USE_MUNMAP
# ifndef MUNMAP_THRESHOLD
# define MUNMAP_THRESHOLD 7
# endif
GC_INNER unsigned GC_unmap_threshold = MUNMAP_THRESHOLD;
# define IF_USE_MUNMAP(x) x
# define COMMA_IF_USE_MUNMAP(x) /* comma */, x
#else
# define IF_USE_MUNMAP(x) /* empty */
# define COMMA_IF_USE_MUNMAP(x) /* empty */
#endif
/* We stop the world and mark from all roots. If stop_func() ever */
/* returns TRUE, we may fail and return FALSE. Increment GC_gc_no if */
/* we succeed. */
STATIC GC_bool GC_stopped_mark(GC_stop_func stop_func)
{
ptr_t cold_gc_frame = GC_approx_sp();
unsigned abandoned_at;
# ifndef NO_CLOCK
CLOCK_TYPE start_time = CLOCK_TYPE_INITIALIZER;
GC_bool start_time_valid = FALSE;
# endif
GC_ASSERT(I_HOLD_LOCK());
GC_ASSERT(GC_is_initialized);
# if !defined(REDIRECT_MALLOC) && defined(USE_WINALLOC)
GC_add_current_malloc_heap();
# endif
# if defined(REGISTER_LIBRARIES_EARLY)
GC_cond_register_dynamic_libraries();
# endif
# if !defined(GC_NO_FINALIZATION) && !defined(GC_TOGGLE_REFS_NOT_NEEDED)
GC_process_togglerefs();
# endif
/* Output blank line for convenience here. */
GC_COND_LOG_PRINTF(
"\n--> Marking for collection #%lu after %lu allocated bytes\n",
(unsigned long)GC_gc_no + 1, (unsigned long)GC_bytes_allocd);
# ifndef NO_CLOCK
if (GC_PRINT_STATS_FLAG || measure_performance) {
GET_TIME(start_time);
start_time_valid = TRUE;
}
# endif
# ifdef THREADS
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_PRE_STOP_WORLD);
# endif
STOP_WORLD();
# ifdef THREADS
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_POST_STOP_WORLD);
# ifdef THREAD_LOCAL_ALLOC
GC_world_stopped = TRUE;
# elif defined(CPPCHECK)
(void)0; /* workaround a warning about adjacent same "if" condition */
# endif
# endif
# ifdef MAKE_BACK_GRAPH
if (GC_print_back_height) {
GC_build_back_graph();
}
# endif
/* Notify about marking from all roots. */
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_MARK_START);
/* Minimize junk left in my registers and on the stack. */
GC_clear_a_few_frames();
GC_noop6(0,0,0,0,0,0);
GC_initiate_gc();
# ifdef PARALLEL_MARK
if (stop_func != GC_never_stop_func)
GC_parallel_mark_disabled = TRUE;
# endif
for (abandoned_at = 1; !(*stop_func)(); abandoned_at++) {
if (GC_mark_some(cold_gc_frame)) {
# ifdef PARALLEL_MARK
if (GC_parallel && GC_parallel_mark_disabled) {
GC_COND_LOG_PRINTF("Stopped marking done after %u iterations"
" with disabled parallel marker\n",
abandoned_at - 1);
}
# endif
abandoned_at = 0;
break;
}
}
# ifdef PARALLEL_MARK
GC_parallel_mark_disabled = FALSE;
# endif
if (abandoned_at > 0) {
GC_deficit = abandoned_at - 1; /* give the mutator a chance */
/* TODO: Notify GC_EVENT_MARK_ABANDON */
} else {
GC_gc_no++;
/* Check all debugged objects for consistency. */
if (GC_debugging_started) {
(*GC_check_heap)();
}
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_MARK_END);
}
# ifdef THREADS
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_PRE_START_WORLD);
# endif
# ifdef THREAD_LOCAL_ALLOC
GC_world_stopped = FALSE;
# endif
START_WORLD();
# ifdef THREADS
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_POST_START_WORLD);
# endif
# ifndef NO_CLOCK
if (start_time_valid) {
CLOCK_TYPE current_time;
unsigned long time_diff, ns_frac_diff;
/* TODO: Avoid code duplication from GC_try_to_collect_inner */
GET_TIME(current_time);
time_diff = MS_TIME_DIFF(current_time, start_time);
ns_frac_diff = NS_FRAC_TIME_DIFF(current_time, start_time);
if (measure_performance) {
stopped_mark_total_time += time_diff; /* may wrap */
stopped_mark_total_ns_frac += (unsigned32)ns_frac_diff;
if (stopped_mark_total_ns_frac >= (unsigned32)1000000UL) {
stopped_mark_total_ns_frac -= (unsigned32)1000000UL;
stopped_mark_total_time++;
}
}
if (GC_PRINT_STATS_FLAG) {
unsigned total_time = world_stopped_total_time;
unsigned divisor = world_stopped_total_divisor;
/* Compute new world-stop delay total time. */
if (total_time > (((unsigned)-1) >> 1)
|| divisor >= MAX_TOTAL_TIME_DIVISOR) {
/* Halve values if overflow occurs. */
total_time >>= 1;
divisor >>= 1;
}
total_time += time_diff < (((unsigned)-1) >> 1) ?
(unsigned)time_diff : ((unsigned)-1) >> 1;
/* Update old world_stopped_total_time and its divisor. */
world_stopped_total_time = total_time;
world_stopped_total_divisor = ++divisor;
if (0 == abandoned_at) {
GC_ASSERT(divisor != 0);
GC_log_printf("World-stopped marking took %lu ms %lu ns"
" (%u ms in average)\n", time_diff, ns_frac_diff,
total_time / divisor);
}
}
}
# endif
if (0 == abandoned_at) return TRUE;
GC_COND_LOG_PRINTF("Abandoned stopped marking after %u iterations\n",
abandoned_at - 1);
return FALSE;
}
GC_INNER void GC_set_fl_marks(ptr_t q)
{
# ifdef GC_ASSERTIONS
ptr_t q2;
# endif
struct hblk *h = HBLKPTR(q);
const struct hblk *last_h = h;
hdr *hhdr;
# ifdef MARK_BIT_PER_OBJ
size_t sz;
# endif
GC_ASSERT(q != NULL);
hhdr = HDR(h);
# ifdef MARK_BIT_PER_OBJ
sz = hhdr -> hb_sz;
# endif
# ifdef GC_ASSERTIONS