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alloc.c
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alloc.c
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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved.
* Copyright (c) 1998 by Silicon Graphics. All rights reserved.
* Copyright (c) 1999-2004 Hewlett-Packard Development Company, L.P.
* Copyright (c) 2008-2019 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"
#include <stdio.h>
#if !defined(MACOS) && !defined(MSWINCE)
# include <signal.h>
# if !defined(SN_TARGET_ORBIS) && !defined(SN_TARGET_PSP2) \
&& !defined(__CC_ARM)
# include <sys/types.h>
# endif
#endif
/*
* Separate free lists are maintained for different sized objects
* up to MAXOBJBYTES.
* The call GC_allocobj(i,k) ensures that the freelist for
* kind k objects of size i points 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);
* } 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 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 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;
}
#endif /* !NO_CLOCK */
#ifndef GC_DISABLE_INCREMENTAL
GC_INNER GC_bool GC_incremental = FALSE; /* By default, stop the world. */
#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 do to heap growth. */
#ifdef THREAD_LOCAL_ALLOC
GC_INNER GC_bool GC_world_stopped = FALSE;
#endif
STATIC word GC_used_heap_size_after_full = 0;
/* GC_copyright symbol is externally visible. */
EXTERN_C_BEGIN
extern const char * const GC_copyright[];
EXTERN_C_END
const char * const GC_copyright[] =
{"Copyright 1988, 1989 Hans-J. Boehm and Alan J. Demers ",
"Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. ",
"Copyright (c) 1996-1998 by Silicon Graphics. All rights reserved. ",
"Copyright (c) 1999-2009 by Hewlett-Packard Company. All rights reserved. ",
"Copyright (c) 2008-2019 Ivan Maidanski ",
"THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY",
" EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.",
"See source code for details." };
/* 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 unsigned GC_version;
EXTERN_C_END
const unsigned GC_version = ((GC_VERSION_MAJOR << 16) |
(GC_VERSION_MINOR << 8) | GC_VERSION_MICRO);
#endif
GC_API unsigned GC_CALL GC_get_version(void)
{
return (GC_VERSION_MAJOR << 16) | (GC_VERSION_MINOR << 8) |
GC_VERSION_MICRO;
}
/* 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(0);
}
#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 = 50;
#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 lock. */
GC_API void GC_CALL GC_set_stop_func(GC_stop_func stop_func)
{
DCL_LOCK_STATE;
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;
DCL_LOCK_STATE;
LOCK();
stop_func = GC_default_stop_func;
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;
if ((*GC_default_stop_func)())
return(1);
if ((count++ & 3) != 0) return(0);
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 (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 1;
}
return(0);
}
#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. */
# 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 = GC_approx_sp() - GC_stackbottom;
# else
stack_size = 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 = GC_bytes_allocd;
/* probably client bug or unfortunate scheduling */
}
result += 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. */
return(GC_bytes_allocd >> 3);
} else {
return(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_NWORDS
# define CLEAR_NWORDS 64
# endif
volatile word frames[CLEAR_NWORDS];
BZERO((word *)frames, CLEAR_NWORDS * sizeof(word));
}
/* Heap size at which we need a collection to avoid expanding past */
/* limits used by blacklisting. */
STATIC word GC_collect_at_heapsize = GC_WORD_MAX;
/* 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;
if (last_gc_no != GC_gc_no) {
last_min_bytes_allocd = min_bytes_allocd();
last_gc_no = GC_gc_no;
}
return(GC_adj_bytes_allocd() >= last_min_bytes_allocd
|| GC_heapsize >= GC_collect_at_heapsize);
}
/* STATIC */ GC_start_callback_proc GC_start_call_back = 0;
/* Called at start of full collections. */
/* Not called if 0. Called with the allocation */
/* lock held. Not used by GC itself. */
GC_API void GC_CALL GC_set_start_callback(GC_start_callback_proc fn)
{
DCL_LOCK_STATE;
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;
DCL_LOCK_STATE;
LOCK();
fn = GC_start_call_back;
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)
{
GC_ASSERT(I_HOLD_LOCK());
ASSERT_CANCEL_DISABLED();
if (GC_should_collect()) {
static int n_partial_gcs = 0;
if (!GC_incremental) {
/* TODO: If possible, GC_default_stop_func should be used here */
GC_try_to_collect_inner(GC_never_stop_func);
n_partial_gcs = 0;
return;
} else {
# 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++;
}
}
/* We try to mark with the world stopped. */
/* If we run out of time, this turns into */
/* incremental marking. */
# ifndef NO_CLOCK
if (GC_time_limit != GC_TIME_UNLIMITED) { GET_TIME(GC_start_time); }
# endif
/* TODO: If possible, GC_default_stop_func should be */
/* used instead of GC_never_stop_func here. */
if (GC_stopped_mark(GC_time_limit == GC_TIME_UNLIMITED?
GC_never_stop_func : GC_timeout_stop_func)) {
# ifdef SAVE_CALL_CHAIN
GC_save_callers(GC_last_stack);
# endif
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). */
DCL_LOCK_STATE;
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;
DCL_LOCK_STATE;
LOCK();
fn = GC_on_collection_event;
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());
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. */
while(GC_collection_in_progress()) {
if ((*stop_func)()) {
/* TODO: Notify GC_EVENT_ABANDON */
return(FALSE);
}
GC_collect_a_little_inner(1);
}
}
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();
# ifdef SAVE_CALL_CHAIN
GC_save_callers(GC_last_stack);
# endif
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;
GET_TIME(current_time);
time_diff = MS_TIME_DIFF(current_time, start_time);
if (measure_performance)
full_gc_total_time += time_diff; /* may wrap */
if (GC_print_stats)
GC_log_printf("Complete collection took %lu ms %lu ns\n", time_diff,
NS_FRAC_TIME_DIFF(current_time, start_time));
}
# endif
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_END);
return(TRUE);
}
/*
* Perform n units of garbage collection work. A unit is intended to touch
* roughly GC_rate pages. 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.
*/
#ifndef GC_RATE
# define GC_RATE 10
#endif
#ifndef MAX_PRIOR_ATTEMPTS
# define MAX_PRIOR_ATTEMPTS 1
#endif
/* 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. Doesn't count the initial root scan */
/* for a full GC. */
STATIC int GC_deficit = 0;/* The number of extra calls to GC_mark_some */
/* that we have made. */
STATIC int GC_rate = GC_RATE;
GC_API void GC_CALL GC_set_rate(int value)
{
GC_ASSERT(value > 0);
GC_rate = value;
}
GC_API int GC_CALL GC_get_rate(void)
{
return GC_rate;
}
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(int n)
{
IF_CANCEL(int cancel_state;)
GC_ASSERT(I_HOLD_LOCK());
if (GC_dont_gc) return;
DISABLE_CANCEL(cancel_state);
if (GC_incremental && GC_collection_in_progress()) {
int i;
int max_deficit = GC_rate * n;
# 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) {
/* Need to finish a collection. */
# ifdef SAVE_CALL_CHAIN
GC_save_callers(GC_last_stack);
# endif
# ifdef PARALLEL_MARK
if (GC_parallel)
GC_wait_for_reclaim();
# endif
if (GC_n_attempts < max_prior_attempts
&& GC_time_limit != GC_TIME_UNLIMITED) {
# ifndef NO_CLOCK
GET_TIME(GC_start_time);
# endif
if (GC_stopped_mark(GC_timeout_stop_func)) {
GC_finish_collection();
} else {
GC_n_attempts++;
}
} else {
/* TODO: If possible, GC_default_stop_func should be */
/* used here. */
(void)GC_stopped_mark(GC_never_stop_func);
GC_finish_collection();
}
}
if (GC_deficit > 0) {
GC_deficit -= max_deficit;
if (GC_deficit < 0)
GC_deficit = 0;
}
} else {
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;
DCL_LOCK_STATE;
LOCK();
GC_collect_a_little_inner(1);
result = (int)GC_collection_in_progress();
UNLOCK();
if (!result && GC_debugging_started) GC_print_all_smashed();
return(result);
}
#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
# 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)
{
int i;
# ifndef NO_CLOCK
CLOCK_TYPE start_time = CLOCK_TYPE_INITIALIZER;
# endif
GC_ASSERT(I_HOLD_LOCK());
# if !defined(REDIRECT_MALLOC) && defined(USE_WINALLOC)
GC_add_current_malloc_heap();
# endif
# if defined(REGISTER_LIBRARIES_EARLY)
GC_cond_register_dynamic_libraries();
# endif
# ifndef NO_CLOCK
if (GC_PRINT_STATS_FLAG)
GET_TIME(start_time);
# endif
# if !defined(GC_NO_FINALIZATION) && !defined(GC_TOGGLE_REFS_NOT_NEEDED)
GC_process_togglerefs();
# 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);
# endif
# ifdef THREAD_LOCAL_ALLOC
GC_world_stopped = TRUE;
# 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);
# ifdef MAKE_BACK_GRAPH
if (GC_print_back_height) {
GC_build_back_graph();
}
# endif
/* Mark 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 (i = 0; !(*stop_func)(); i++) {
if (GC_mark_some(GC_approx_sp())) {
# ifdef PARALLEL_MARK
if (GC_parallel && GC_parallel_mark_disabled) {
GC_COND_LOG_PRINTF("Stopped marking done after %d iterations"
" with disabled parallel marker\n", i);
}
# endif
i = -1;
break;
}
}
# ifdef PARALLEL_MARK
GC_parallel_mark_disabled = FALSE;
# endif
if (i >= 0) {
GC_COND_LOG_PRINTF("Abandoned stopped marking after"
" %d iterations\n", i);
GC_deficit = i; /* Give the mutator a chance. */
# ifdef THREAD_LOCAL_ALLOC
GC_world_stopped = FALSE;
# endif
# ifdef THREADS
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_PRE_START_WORLD);
# endif
START_WORLD();
# ifdef THREADS
if (GC_on_collection_event)
GC_on_collection_event(GC_EVENT_POST_START_WORLD);
# endif
/* TODO: Notify GC_EVENT_MARK_ABANDON */
return FALSE;
}
GC_gc_no++;
GC_DBGLOG_PRINTF("GC #%lu freed %ld bytes, heap %lu KiB"
IF_USE_MUNMAP(" (+ %lu KiB unmapped)") "\n",
(unsigned long)GC_gc_no, (long)GC_bytes_found,
TO_KiB_UL(GC_heapsize - GC_unmapped_bytes) /*, */
COMMA_IF_USE_MUNMAP(TO_KiB_UL(GC_unmapped_bytes)));
/* 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
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 (GC_PRINT_STATS_FLAG) {
unsigned long time_diff;
unsigned total_time, divisor;
CLOCK_TYPE current_time;
GET_TIME(current_time);
time_diff = MS_TIME_DIFF(current_time,start_time);
/* Compute new world-stop delay total time */
total_time = world_stopped_total_time;
divisor = world_stopped_total_divisor;
if ((int)total_time < 0 || 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;
GC_ASSERT(divisor != 0);
GC_log_printf("World-stopped marking took %lu ms %lu ns"
" (%u ms in average)\n",
time_diff, NS_FRAC_TIME_DIFF(current_time, start_time),
total_time / divisor);
}
# endif
return(TRUE);
}
/* Set all mark bits for the free list whose first entry is q */
GC_INNER void GC_set_fl_marks(ptr_t q)
{
if (q != NULL) {
struct hblk *h = HBLKPTR(q);
struct hblk *last_h = h;
hdr *hhdr = HDR(h);
IF_PER_OBJ(word sz = hhdr->hb_sz;)
for (;;) {
word bit_no = MARK_BIT_NO((ptr_t)q - (ptr_t)h, sz);
if (!mark_bit_from_hdr(hhdr, bit_no)) {
set_mark_bit_from_hdr(hhdr, bit_no);
++hhdr -> hb_n_marks;
}
q = (ptr_t)obj_link(q);
if (q == NULL)
break;
h = HBLKPTR(q);
if (h != last_h) {
last_h = h;
hhdr = HDR(h);
IF_PER_OBJ(sz = hhdr->hb_sz;)
}
}
}
}
#if defined(GC_ASSERTIONS) && defined(THREAD_LOCAL_ALLOC)
/* Check that all mark bits for the free list whose first entry is */
/* (*pfreelist) are set. Check skipped if points to a special value. */
void GC_check_fl_marks(void **pfreelist)
{
/* TODO: There is a data race with GC_FAST_MALLOC_GRANS (which does */
/* not do atomic updates to the free-list). The race seems to be */
/* harmless, and for now we just skip this check in case of TSan. */
# if defined(AO_HAVE_load_acquire_read) && !defined(THREAD_SANITIZER)
AO_t *list = (AO_t *)AO_load_acquire_read((AO_t *)pfreelist);
/* Atomic operations are used because the world is running. */
AO_t *prev;
AO_t *p;
if ((word)list <= HBLKSIZE) return;
prev = (AO_t *)pfreelist;
for (p = list; p != NULL;) {
AO_t *next;
if (!GC_is_marked(p)) {
ABORT_ARG2("Unmarked local free list entry",
": object %p on list %p", (void *)p, (void *)list);
}
/* While traversing the free-list, it re-reads the pointer to */
/* the current node before accepting its next pointer and */
/* bails out if the latter has changed. That way, it won't */
/* try to follow the pointer which might be been modified */
/* after the object was returned to the client. It might */
/* perform the mark-check on the just allocated object but */
/* that should be harmless. */
next = (AO_t *)AO_load_acquire_read(p);
if (AO_load(prev) != (AO_t)p)
break;
prev = p;
p = next;
}
# else
/* FIXME: Not implemented (just skipped). */
(void)pfreelist;
# endif
}
#endif /* GC_ASSERTIONS && THREAD_LOCAL_ALLOC */
/* Clear all mark bits for the free list whose first entry is q */
/* Decrement GC_bytes_found by number of bytes on free list. */
STATIC void GC_clear_fl_marks(ptr_t q)
{
struct hblk *h = HBLKPTR(q);
struct hblk *last_h = h;
hdr *hhdr = HDR(h);
word sz = hhdr->hb_sz; /* Normally set only once. */