forked from erlang/otp
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erl_gc.c
2509 lines (2221 loc) · 64.3 KB
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erl_gc.c
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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2002-2010. All Rights Reserved.
*
* The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
* compliance with the License. You should have received a copy of the
* Erlang Public License along with this software. If not, it can be
* retrieved online at http://www.erlang.org/.
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* %CopyrightEnd%
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "sys.h"
#include "erl_vm.h"
#include "global.h"
#include "erl_process.h"
#include "erl_db.h"
#include "beam_catches.h"
#include "erl_binary.h"
#include "erl_bits.h"
#include "error.h"
#include "big.h"
#include "erl_gc.h"
#if HIPE
#include "hipe_stack.h"
#endif
#define ERTS_INACT_WR_PB_LEAVE_MUCH_LIMIT 1
#define ERTS_INACT_WR_PB_LEAVE_MUCH_PERCENTAGE 20
#define ERTS_INACT_WR_PB_LEAVE_LIMIT 10
#define ERTS_INACT_WR_PB_LEAVE_PERCENTAGE 10
/*
* Returns number of elements in an array.
*/
#define ALENGTH(a) (sizeof(a)/sizeof(a[0]))
static erts_smp_spinlock_t info_lck;
static Uint garbage_cols; /* no of garbage collections */
static Uint reclaimed; /* no of words reclaimed in GCs */
# define STACK_SZ_ON_HEAP(p) ((p)->hend - (p)->stop)
# define OverRunCheck(P) \
if ((P)->stop < (P)->htop) { \
erts_fprintf(stderr, "hend=%p\n", (p)->hend); \
erts_fprintf(stderr, "stop=%p\n", (p)->stop); \
erts_fprintf(stderr, "htop=%p\n", (p)->htop); \
erts_fprintf(stderr, "heap=%p\n", (p)->heap); \
erl_exit(ERTS_ABORT_EXIT, "%s, line %d: %T: Overrun stack and heap\n", \
__FILE__,__LINE__,(P)->id); \
}
#ifdef DEBUG
#define ErtsGcQuickSanityCheck(P) \
do { \
ASSERT((P)->heap < (P)->hend); \
ASSERT((P)->heap_sz == (P)->hend - (P)->heap); \
ASSERT((P)->heap <= (P)->htop && (P)->htop <= (P)->hend); \
ASSERT((P)->heap <= (P)->stop && (P)->stop <= (P)->hend); \
ASSERT((P)->heap <= (P)->high_water && (P)->high_water <= (P)->hend);\
OverRunCheck((P)); \
} while (0)
#else
#define ErtsGcQuickSanityCheck(P) \
do { \
OverRunCheck((P)); \
} while (0)
#endif
/*
* This structure describes the rootset for the GC.
*/
typedef struct roots {
Eterm* v; /* Pointers to vectors with terms to GC
* (e.g. the stack).
*/
Uint sz; /* Size of each vector. */
} Roots;
typedef struct {
Roots def[32]; /* Default storage. */
Roots* roots; /* Pointer to root set array. */
Uint size; /* Storage size. */
int num_roots; /* Number of root arrays. */
} Rootset;
static Uint setup_rootset(Process*, Eterm*, int, Rootset*);
static void cleanup_rootset(Rootset *rootset);
static Uint combined_message_size(Process* p);
static void remove_message_buffers(Process* p);
static int major_collection(Process* p, int need, Eterm* objv, int nobj, Uint *recl);
static int minor_collection(Process* p, int need, Eterm* objv, int nobj, Uint *recl);
static void do_minor(Process *p, int new_sz, Eterm* objv, int nobj);
static Eterm* sweep_rootset(Rootset *rootset, Eterm* htop, char* src, Uint src_size);
static Eterm* sweep_one_area(Eterm* n_hp, Eterm* n_htop, char* src, Uint src_size);
static Eterm* sweep_one_heap(Eterm* heap_ptr, Eterm* heap_end, Eterm* htop,
char* src, Uint src_size);
static Eterm* collect_heap_frags(Process* p, Eterm* heap,
Eterm* htop, Eterm* objv, int nobj);
static Uint adjust_after_fullsweep(Process *p, int size_before,
int need, Eterm *objv, int nobj);
static void shrink_new_heap(Process *p, Uint new_sz, Eterm *objv, int nobj);
static void grow_new_heap(Process *p, Uint new_sz, Eterm* objv, int nobj);
static void sweep_off_heap(Process *p, int fullsweep);
static void offset_heap(Eterm* hp, Uint sz, Sint offs, char* area, Uint area_size);
static void offset_heap_ptr(Eterm* hp, Uint sz, Sint offs, char* area, Uint area_size);
static void offset_rootset(Process *p, Sint offs, char* area, Uint area_size,
Eterm* objv, int nobj);
static void offset_off_heap(Process* p, Sint offs, char* area, Uint area_size);
static void offset_mqueue(Process *p, Sint offs, char* area, Uint area_size);
#ifdef HARDDEBUG
static void disallow_heap_frag_ref_in_heap(Process* p);
static void disallow_heap_frag_ref_in_old_heap(Process* p);
static void disallow_heap_frag_ref(Process* p, Eterm* n_htop, Eterm* objv, int nobj);
#endif
#if defined(ARCH_64) && !HALFWORD_HEAP
# define MAX_HEAP_SIZES 154
#else
# define MAX_HEAP_SIZES 55
#endif
static Sint heap_sizes[MAX_HEAP_SIZES]; /* Suitable heap sizes. */
static int num_heap_sizes; /* Number of heap sizes. */
Uint erts_test_long_gc_sleep; /* Only used for testing... */
/*
* Initialize GC global data.
*/
void
erts_init_gc(void)
{
int i = 0;
ASSERT(offsetof(ProcBin,thing_word) == offsetof(struct erl_off_heap_header,thing_word));
ASSERT(offsetof(ProcBin,thing_word) == offsetof(ErlFunThing,thing_word));
ASSERT(offsetof(ProcBin,thing_word) == offsetof(ExternalThing,header));
ASSERT(offsetof(ProcBin,size) == offsetof(struct erl_off_heap_header,size));
ASSERT(offsetof(ProcBin,size) == offsetof(ErlSubBin,size));
ASSERT(offsetof(ProcBin,size) == offsetof(ErlHeapBin,size));
ASSERT(offsetof(ProcBin,next) == offsetof(struct erl_off_heap_header,next));
ASSERT(offsetof(ProcBin,next) == offsetof(ErlFunThing,next));
ASSERT(offsetof(ProcBin,next) == offsetof(ExternalThing,next));
erts_smp_spinlock_init(&info_lck, "gc_info");
garbage_cols = 0;
reclaimed = 0;
erts_test_long_gc_sleep = 0;
/*
* Heap sizes start growing in a Fibonacci sequence.
*
* Fib growth is not really ok for really large heaps, for
* example is fib(35) == 14meg, whereas fib(36) == 24meg;
* we really don't want that growth when the heaps are that big.
*/
heap_sizes[0] = 34;
heap_sizes[1] = 55;
for (i = 2; i < 23; i++) {
heap_sizes[i] = heap_sizes[i-1] + heap_sizes[i-2];
}
/* At 1.3 mega words heap, we start to slow down. */
for (i = 23; i < ALENGTH(heap_sizes); i++) {
heap_sizes[i] = 5*(heap_sizes[i-1]/4);
if (heap_sizes[i] < 0) {
/* Size turned negative. Discard this last size. */
i--;
break;
}
}
num_heap_sizes = i;
}
/*
* Find the next heap size equal to or greater than the given size (if offset == 0).
*
* If offset is 1, the next higher heap size is returned (always greater than size).
*/
Uint
erts_next_heap_size(Uint size, Uint offset)
{
if (size < heap_sizes[0]) {
return heap_sizes[0];
} else {
Sint* low = heap_sizes;
Sint* high = heap_sizes + num_heap_sizes;
Sint* mid;
while (low < high) {
mid = low + (high-low) / 2;
if (size < mid[0]) {
high = mid;
} else if (size == mid[0]) {
ASSERT(mid+offset-heap_sizes < num_heap_sizes);
return mid[offset];
} else if (size < mid[1]) {
ASSERT(mid[0] < size && size <= mid[1]);
ASSERT(mid+offset-heap_sizes < num_heap_sizes);
return mid[offset+1];
} else {
low = mid + 1;
}
}
erl_exit(1, "no next heap size found: %d, offset %d\n", size, offset);
}
return 0;
}
/*
* Return the next heap size to use. Make sure we never return
* a smaller heap size than the minimum heap size for the process.
* (Use of the erlang:hibernate/3 BIF could have shrinked the
* heap below the minimum heap size.)
*/
static Uint
next_heap_size(Process* p, Uint size, Uint offset)
{
size = erts_next_heap_size(size, offset);
return size < p->min_heap_size ? p->min_heap_size : size;
}
Eterm
erts_heap_sizes(Process* p)
{
int i;
int n = 0;
int big = 0;
Eterm res = NIL;
Eterm* hp;
Eterm* bigp;
for (i = num_heap_sizes-1; i >= 0; i--) {
n += 2;
if (!MY_IS_SSMALL(heap_sizes[i])) {
big += BIG_UINT_HEAP_SIZE;
}
}
/*
* We store all big numbers first on the heap, followed
* by all the cons cells.
*/
bigp = HAlloc(p, n+big);
hp = bigp+big;
for (i = num_heap_sizes-1; i >= 0; i--) {
Eterm num;
Sint sz = heap_sizes[i];
if (MY_IS_SSMALL(sz)) {
num = make_small(sz);
} else {
num = uint_to_big(sz, bigp);
bigp += BIG_UINT_HEAP_SIZE;
}
res = CONS(hp, num, res);
hp += 2;
}
return res;
}
void
erts_gc_info(ErtsGCInfo *gcip)
{
if (gcip) {
erts_smp_spin_lock(&info_lck);
gcip->garbage_collections = garbage_cols;
gcip->reclaimed = reclaimed;
erts_smp_spin_unlock(&info_lck);
}
}
void
erts_offset_heap(Eterm* hp, Uint sz, Sint offs, Eterm* low, Eterm* high)
{
offset_heap(hp, sz, offs, (char*) low, ((char *)high)-((char *)low));
}
void
erts_offset_heap_ptr(Eterm* hp, Uint sz, Sint offs,
Eterm* low, Eterm* high)
{
offset_heap_ptr(hp, sz, offs, (char *) low, ((char *)high)-((char *)low));
}
#define ptr_within(ptr, low, high) ((ptr) < (high) && (ptr) >= (low))
void
erts_offset_off_heap(ErlOffHeap *ohp, Sint offs, Eterm* low, Eterm* high)
{
if (ohp->first && ptr_within((Eterm *)ohp->first, low, high)) {
Eterm** uptr = (Eterm**) (void *) &ohp->first;
*uptr += offs;
}
}
#undef ptr_within
Eterm
erts_gc_after_bif_call(Process* p, Eterm result, Eterm* regs, Uint arity)
{
int cost;
if (is_non_value(result)) {
if (p->freason == TRAP) {
cost = erts_garbage_collect(p, 0, p->def_arg_reg, p->arity);
} else {
cost = erts_garbage_collect(p, 0, regs, arity);
}
} else {
Eterm val[1];
val[0] = result;
cost = erts_garbage_collect(p, 0, val, 1);
result = val[0];
}
BUMP_REDS(p, cost);
return result;
}
/*
* Garbage collect a process.
*
* p: Pointer to the process structure.
* need: Number of Eterm words needed on the heap.
* objv: Array of terms to add to rootset; that is to preserve.
* nobj: Number of objects in objv.
*/
int
erts_garbage_collect(Process* p, int need, Eterm* objv, int nobj)
{
Uint reclaimed_now = 0;
int done = 0;
Uint ms1, s1, us1;
if (IS_TRACED_FL(p, F_TRACE_GC)) {
trace_gc(p, am_gc_start);
}
erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
p->gcstatus = p->status;
p->status = P_GARBING;
if (erts_system_monitor_long_gc != 0) {
get_now(&ms1, &s1, &us1);
}
erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
erts_smp_locked_activity_begin(ERTS_ACTIVITY_GC);
ERTS_CHK_OFFHEAP(p);
ErtsGcQuickSanityCheck(p);
if (GEN_GCS(p) >= MAX_GEN_GCS(p)) {
FLAGS(p) |= F_NEED_FULLSWEEP;
}
/*
* Test which type of GC to do.
*/
while (!done) {
if ((FLAGS(p) & F_NEED_FULLSWEEP) != 0) {
done = major_collection(p, need, objv, nobj, &reclaimed_now);
} else {
done = minor_collection(p, need, objv, nobj, &reclaimed_now);
}
}
/*
* Finish.
*/
ERTS_CHK_OFFHEAP(p);
ErtsGcQuickSanityCheck(p);
erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
p->status = p->gcstatus;
erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
if (IS_TRACED_FL(p, F_TRACE_GC)) {
trace_gc(p, am_gc_end);
}
erts_smp_locked_activity_end(ERTS_ACTIVITY_GC);
if (erts_system_monitor_long_gc != 0) {
Uint ms2, s2, us2;
Sint t;
if (erts_test_long_gc_sleep)
while (0 != erts_milli_sleep(erts_test_long_gc_sleep));
get_now(&ms2, &s2, &us2);
t = ms2 - ms1;
t = t*1000000 + s2 - s1;
t = t*1000 + ((Sint) (us2 - us1))/1000;
if (t > 0 && (Uint)t > erts_system_monitor_long_gc) {
monitor_long_gc(p, t);
}
}
if (erts_system_monitor_large_heap != 0) {
Uint size = HEAP_SIZE(p);
size += OLD_HEAP(p) ? OLD_HEND(p) - OLD_HEAP(p) : 0;
if (size >= erts_system_monitor_large_heap)
monitor_large_heap(p);
}
erts_smp_spin_lock(&info_lck);
garbage_cols++;
reclaimed += reclaimed_now;
erts_smp_spin_unlock(&info_lck);
FLAGS(p) &= ~F_FORCE_GC;
#ifdef CHECK_FOR_HOLES
/*
* We intentionally do not rescan the areas copied by the GC.
* We trust the GC not to leave any holes.
*/
p->last_htop = p->htop;
p->last_mbuf = 0;
#endif
#ifdef DEBUG
/*
* The scanning for pointers from the old_heap into the new_heap or
* heap fragments turned out to be costly, so we remember how far we
* have scanned this time and will start scanning there next time.
* (We will not detect wild writes into the old heap, or modifications
* of the old heap in-between garbage collections.)
*/
p->last_old_htop = p->old_htop;
#endif
return ((int) (HEAP_TOP(p) - HEAP_START(p)) / 10);
}
/*
* Place all living data on a the new heap; deallocate any old heap.
* Meant to be used by hibernate/3.
*/
void
erts_garbage_collect_hibernate(Process* p)
{
Uint heap_size;
Eterm* heap;
Eterm* htop;
Rootset rootset;
int n;
char* src;
Uint src_size;
Uint actual_size;
char* area;
Uint area_size;
Sint offs;
/*
* Preliminaries.
*/
erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
p->gcstatus = p->status;
p->status = P_GARBING;
erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
erts_smp_locked_activity_begin(ERTS_ACTIVITY_GC);
ErtsGcQuickSanityCheck(p);
ASSERT(p->mbuf_sz == 0);
ASSERT(p->mbuf == 0);
ASSERT(p->stop == p->hend); /* Stack must be empty. */
/*
* Do it.
*/
heap_size = p->heap_sz + (p->old_htop - p->old_heap);
heap = (Eterm*) ERTS_HEAP_ALLOC(ERTS_ALC_T_TMP_HEAP,
sizeof(Eterm)*heap_size);
htop = heap;
n = setup_rootset(p, p->arg_reg, p->arity, &rootset);
src = (char *) p->heap;
src_size = (char *) p->htop - src;
htop = sweep_rootset(&rootset, htop, src, src_size);
htop = sweep_one_area(heap, htop, src, src_size);
if (p->old_heap) {
src = (char *) p->old_heap;
src_size = (char *) p->old_htop - src;
htop = sweep_rootset(&rootset, htop, src, src_size);
htop = sweep_one_area(heap, htop, src, src_size);
}
cleanup_rootset(&rootset);
if (MSO(p).first) {
sweep_off_heap(p, 1);
}
/*
* Update all pointers.
*/
ERTS_HEAP_FREE(ERTS_ALC_T_HEAP,
(void*)HEAP_START(p),
HEAP_SIZE(p) * sizeof(Eterm));
if (p->old_heap) {
ERTS_HEAP_FREE(ERTS_ALC_T_OLD_HEAP,
(void*)p->old_heap,
(p->old_hend - p->old_heap) * sizeof(Eterm));
p->old_heap = p->old_htop = p->old_hend = 0;
}
p->heap = heap;
p->high_water = htop;
p->htop = htop;
p->hend = p->heap + heap_size;
p->stop = p->hend;
p->heap_sz = heap_size;
heap_size = actual_size = p->htop - p->heap;
if (heap_size == 0) {
heap_size = 1; /* We want a heap... */
}
FLAGS(p) &= ~F_FORCE_GC;
/*
* Move the heap to its final destination.
*
* IMPORTANT: We have garbage collected to a temporary heap and
* then copy the result to a newly allocated heap of exact size.
* This is intentional and important! Garbage collecting as usual
* and then shrinking the heap by reallocating it caused serious
* fragmentation problems when large amounts of processes were
* hibernated.
*/
ASSERT(p->hend - p->stop == 0); /* Empty stack */
ASSERT(actual_size < p->heap_sz);
heap = ERTS_HEAP_ALLOC(ERTS_ALC_T_HEAP, sizeof(Eterm)*heap_size);
sys_memcpy((void *) heap, (void *) p->heap, actual_size*sizeof(Eterm));
ERTS_HEAP_FREE(ERTS_ALC_T_TMP_HEAP, p->heap, p->heap_sz*sizeof(Eterm));
p->stop = p->hend = heap + heap_size;
offs = heap - p->heap;
area = (char *) p->heap;
area_size = ((char *) p->htop) - area;
offset_heap(heap, actual_size, offs, area, area_size);
p->high_water = heap + (p->high_water - p->heap);
offset_rootset(p, offs, area, area_size, p->arg_reg, p->arity);
p->htop = heap + actual_size;
p->heap = heap;
p->heap_sz = heap_size;
#ifdef CHECK_FOR_HOLES
p->last_htop = p->htop;
p->last_mbuf = 0;
#endif
#ifdef DEBUG
p->last_old_htop = NULL;
#endif
/*
* Finishing.
*/
ErtsGcQuickSanityCheck(p);
erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
p->status = p->gcstatus;
erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
erts_smp_locked_activity_end(ERTS_ACTIVITY_GC);
}
void
erts_garbage_collect_literals(Process* p, Eterm* literals, Uint lit_size)
{
Uint byte_lit_size = sizeof(Eterm)*lit_size;
Uint old_heap_size;
Eterm* temp_lit;
Sint offs;
Rootset rootset; /* Rootset for GC (stack, dictionary, etc). */
Roots* roots;
char* area;
Uint area_size;
Eterm* old_htop;
int n;
/*
* Set GC state.
*/
erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
p->gcstatus = p->status;
p->status = P_GARBING;
erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
erts_smp_locked_activity_begin(ERTS_ACTIVITY_GC);
/*
* We assume that the caller has already done a major collection
* (which has discarded the old heap), so that we don't have to cope
* with pointer to literals on the old heap. We will now allocate
* an old heap to contain the literals.
*/
ASSERT(p->old_heap == 0); /* Must NOT have an old heap yet. */
old_heap_size = erts_next_heap_size(lit_size, 0);
p->old_heap = p->old_htop = (Eterm*) ERTS_HEAP_ALLOC(ERTS_ALC_T_OLD_HEAP,
sizeof(Eterm)*old_heap_size);
p->old_hend = p->old_heap + old_heap_size;
/*
* We soon want to garbage collect the literals. But since a GC is
* destructive (MOVED markers are written), we must copy the literals
* to a temporary area and change all references to literals.
*/
temp_lit = (Eterm *) erts_alloc(ERTS_ALC_T_TMP, byte_lit_size);
sys_memcpy(temp_lit, literals, byte_lit_size);
offs = temp_lit - literals;
offset_heap(temp_lit, lit_size, offs, (char *) literals, byte_lit_size);
offset_heap(p->heap, p->htop - p->heap, offs, (char *) literals, byte_lit_size);
offset_rootset(p, offs, (char *) literals, byte_lit_size, p->arg_reg, p->arity);
/*
* Now the literals are placed in memory that is safe to write into,
* so now we GC the literals into the old heap. First we go through the
* rootset.
*/
area = (char *) temp_lit;
area_size = byte_lit_size;
n = setup_rootset(p, p->arg_reg, p->arity, &rootset);
roots = rootset.roots;
old_htop = p->old_htop;
while (n--) {
Eterm* g_ptr = roots->v;
Uint g_sz = roots->sz;
Eterm* ptr;
Eterm val;
roots++;
while (g_sz--) {
Eterm gval = *g_ptr;
switch (primary_tag(gval)) {
case TAG_PRIMARY_BOXED:
ptr = boxed_val(gval);
val = *ptr;
if (IS_MOVED_BOXED(val)) {
ASSERT(is_boxed(val));
*g_ptr++ = val;
} else if (in_area(ptr, area, area_size)) {
MOVE_BOXED(ptr,val,old_htop,g_ptr++);
} else {
g_ptr++;
}
break;
case TAG_PRIMARY_LIST:
ptr = list_val(gval);
val = *ptr;
if (IS_MOVED_CONS(val)) { /* Moved */
*g_ptr++ = ptr[1];
} else if (in_area(ptr, area, area_size)) {
MOVE_CONS(ptr,val,old_htop,g_ptr++);
} else {
g_ptr++;
}
break;
default:
g_ptr++;
break;
}
}
}
ASSERT(p->old_htop <= old_htop && old_htop <= p->old_hend);
cleanup_rootset(&rootset);
/*
* Now all references in the rootset to the literals have been updated.
* Now we'll have to go through all heaps updating all other references.
*/
old_htop = sweep_one_heap(p->heap, p->htop, old_htop, area, area_size);
old_htop = sweep_one_area(p->old_heap, old_htop, area, area_size);
ASSERT(p->old_htop <= old_htop && old_htop <= p->old_hend);
p->old_htop = old_htop;
/*
* We no longer need this temporary area.
*/
erts_free(ERTS_ALC_T_TMP, (void *) temp_lit);
/*
* Restore status.
*/
erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
p->status = p->gcstatus;
erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
erts_smp_locked_activity_end(ERTS_ACTIVITY_GC);
}
static int
minor_collection(Process* p, int need, Eterm* objv, int nobj, Uint *recl)
{
Uint mature = HIGH_WATER(p) - HEAP_START(p);
/*
* Allocate an old heap if we don't have one and if we'll need one.
*/
if (OLD_HEAP(p) == NULL && mature != 0) {
Eterm* n_old;
/* Note: We choose a larger heap size than strictly needed,
* which seems to reduce the number of fullsweeps.
* This improved Estone by more than 1200 estones on my computer
* (Ultra Sparc 10).
*/
size_t new_sz = erts_next_heap_size(HEAP_TOP(p) - HEAP_START(p), 1);
/* Create new, empty old_heap */
n_old = (Eterm *) ERTS_HEAP_ALLOC(ERTS_ALC_T_OLD_HEAP,
sizeof(Eterm)*new_sz);
OLD_HEND(p) = n_old + new_sz;
OLD_HEAP(p) = OLD_HTOP(p) = n_old;
}
/*
* Do a minor collection if there is an old heap and if it
* is large enough.
*/
if (OLD_HEAP(p) && mature <= OLD_HEND(p) - OLD_HTOP(p)) {
ErlMessage *msgp;
Uint size_after;
Uint need_after;
Uint stack_size = STACK_SZ_ON_HEAP(p);
Uint fragments = MBUF_SIZE(p) + combined_message_size(p);
Uint size_before = fragments + (HEAP_TOP(p) - HEAP_START(p));
Uint new_sz = next_heap_size(p, HEAP_SIZE(p) + fragments, 0);
do_minor(p, new_sz, objv, nobj);
/*
* Copy newly received message onto the end of the new heap.
*/
ErtsGcQuickSanityCheck(p);
for (msgp = p->msg.first; msgp; msgp = msgp->next) {
if (msgp->data.attached) {
erts_move_msg_attached_data_to_heap(&p->htop, &p->off_heap, msgp);
ErtsGcQuickSanityCheck(p);
}
}
ErtsGcQuickSanityCheck(p);
GEN_GCS(p)++;
size_after = HEAP_TOP(p) - HEAP_START(p);
need_after = size_after + need + stack_size;
*recl += (size_before - size_after);
/*
* Excessively large heaps should be shrunk, but
* don't even bother on reasonable small heaps.
*
* The reason for this is that after tenuring, we often
* use a really small portion of new heap, therefore, unless
* the heap size is substantial, we don't want to shrink.
*/
if ((HEAP_SIZE(p) > 3000) && (4 * need_after < HEAP_SIZE(p)) &&
((HEAP_SIZE(p) > 8000) ||
(HEAP_SIZE(p) > (OLD_HEND(p) - OLD_HEAP(p))))) {
Uint wanted = 3 * need_after;
Uint old_heap_sz = OLD_HEND(p) - OLD_HEAP(p);
/*
* Additional test to make sure we don't make the heap too small
* compared to the size of the older generation heap.
*/
if (wanted*9 < old_heap_sz) {
Uint new_wanted = old_heap_sz / 8;
if (new_wanted > wanted) {
wanted = new_wanted;
}
}
if (wanted < MIN_HEAP_SIZE(p)) {
wanted = MIN_HEAP_SIZE(p);
} else {
wanted = next_heap_size(p, wanted, 0);
}
if (wanted < HEAP_SIZE(p)) {
shrink_new_heap(p, wanted, objv, nobj);
}
ASSERT(HEAP_SIZE(p) == next_heap_size(p, HEAP_SIZE(p), 0));
return 1; /* We are done. */
}
if (HEAP_SIZE(p) >= need_after) {
/*
* The heap size turned out to be just right. We are done.
*/
ASSERT(HEAP_SIZE(p) == next_heap_size(p, HEAP_SIZE(p), 0));
return 1;
}
}
/*
* Still not enough room after minor collection. Must force a major collection.
*/
FLAGS(p) |= F_NEED_FULLSWEEP;
return 0;
}
/*
* HiPE native code stack scanning procedures:
* - fullsweep_nstack()
* - gensweep_nstack()
* - offset_nstack()
*/
#if defined(HIPE)
#define GENSWEEP_NSTACK(p,old_htop,n_htop) \
do { \
Eterm *tmp_old_htop = old_htop; \
Eterm *tmp_n_htop = n_htop; \
gensweep_nstack((p), &tmp_old_htop, &tmp_n_htop); \
old_htop = tmp_old_htop; \
n_htop = tmp_n_htop; \
} while(0)
/*
* offset_nstack() can ignore the descriptor-based traversal the other
* nstack procedures use and simply call offset_heap_ptr() instead.
* This relies on two facts:
* 1. The only live non-Erlang terms on an nstack are return addresses,
* and they will be skipped thanks to the low/high range check.
* 2. Dead values, even if mistaken for pointers into the low/high area,
* can be offset safely since they won't be dereferenced.
*
* XXX: WARNING: If HiPE starts storing other non-Erlang values on the
* nstack, such as floats, then this will have to be changed.
*/
#define offset_nstack(p,offs,area,area_size) offset_heap_ptr(hipe_nstack_start((p)),hipe_nstack_used((p)),(offs),(area),(area_size))
#else /* !HIPE */
#define fullsweep_nstack(p,n_htop) (n_htop)
#define GENSWEEP_NSTACK(p,old_htop,n_htop) do{}while(0)
#define offset_nstack(p,offs,area,area_size) do{}while(0)
#endif /* HIPE */
static void
do_minor(Process *p, int new_sz, Eterm* objv, int nobj)
{
Rootset rootset; /* Rootset for GC (stack, dictionary, etc). */
Roots* roots;
Eterm* n_htop;
int n;
Eterm* ptr;
Eterm val;
Eterm gval;
char* heap = (char *) HEAP_START(p);
Uint heap_size = (char *) HEAP_TOP(p) - heap;
Uint mature_size = (char *) HIGH_WATER(p) - heap;
Eterm* old_htop = OLD_HTOP(p);
Eterm* n_heap;
n_htop = n_heap = (Eterm*) ERTS_HEAP_ALLOC(ERTS_ALC_T_HEAP,
sizeof(Eterm)*new_sz);
if (MBUF(p) != NULL) {
n_htop = collect_heap_frags(p, n_heap, n_htop, objv, nobj);
}
n = setup_rootset(p, objv, nobj, &rootset);
roots = rootset.roots;
GENSWEEP_NSTACK(p, old_htop, n_htop);
while (n--) {
Eterm* g_ptr = roots->v;
Uint g_sz = roots->sz;
roots++;
while (g_sz--) {
gval = *g_ptr;
switch (primary_tag(gval)) {
case TAG_PRIMARY_BOXED: {
ptr = boxed_val(gval);
val = *ptr;
if (IS_MOVED_BOXED(val)) {
ASSERT(is_boxed(val));
*g_ptr++ = val;
} else if (in_area(ptr, heap, mature_size)) {
MOVE_BOXED(ptr,val,old_htop,g_ptr++);
} else if (in_area(ptr, heap, heap_size)) {
MOVE_BOXED(ptr,val,n_htop,g_ptr++);
} else {
g_ptr++;
}
break;
}
case TAG_PRIMARY_LIST: {
ptr = list_val(gval);
val = *ptr;
if (IS_MOVED_CONS(val)) { /* Moved */
*g_ptr++ = ptr[1];
} else if (in_area(ptr, heap, mature_size)) {
MOVE_CONS(ptr,val,old_htop,g_ptr++);
} else if (in_area(ptr, heap, heap_size)) {
MOVE_CONS(ptr,val,n_htop,g_ptr++);
} else {
g_ptr++;
}
break;
}
default:
g_ptr++;
break;
}
}
}
cleanup_rootset(&rootset);
/*
* Now all references in the rootset point to the new heap. However,
* most references on the new heap point to the old heap so the next stage
* is to scan through the new heap evacuating data from the old heap
* until all is changed.
*/
if (mature_size == 0) {
n_htop = sweep_one_area(n_heap, n_htop, heap, heap_size);
} else {
Eterm* n_hp = n_heap;
Eterm* ptr;
Eterm val;
Eterm gval;
while (n_hp != n_htop) {
ASSERT(n_hp < n_htop);
gval = *n_hp;
switch (primary_tag(gval)) {
case TAG_PRIMARY_BOXED: {
ptr = boxed_val(gval);
val = *ptr;
if (IS_MOVED_BOXED(val)) {
ASSERT(is_boxed(val));
*n_hp++ = val;
} else if (in_area(ptr, heap, mature_size)) {
MOVE_BOXED(ptr,val,old_htop,n_hp++);
} else if (in_area(ptr, heap, heap_size)) {
MOVE_BOXED(ptr,val,n_htop,n_hp++);
} else {
n_hp++;
}
break;
}
case TAG_PRIMARY_LIST: {
ptr = list_val(gval);
val = *ptr;
if (IS_MOVED_CONS(val)) {
*n_hp++ = ptr[1];
} else if (in_area(ptr, heap, mature_size)) {
MOVE_CONS(ptr,val,old_htop,n_hp++);
} else if (in_area(ptr, heap, heap_size)) {
MOVE_CONS(ptr,val,n_htop,n_hp++);
} else {
n_hp++;
}
break;
}
case TAG_PRIMARY_HEADER: {
if (!header_is_thing(gval))
n_hp++;
else {
if (header_is_bin_matchstate(gval)) {
ErlBinMatchState *ms = (ErlBinMatchState*) n_hp;
ErlBinMatchBuffer *mb = &(ms->mb);
Eterm* origptr = &(mb->orig);
ptr = boxed_val(*origptr);