| version 1.2, 2000/04/10 08:31:30 |
version 1.6, 2002/07/24 08:00:06 |
|
|
| * modified is included with the above copyright notice. |
* modified is included with the above copyright notice. |
| */ |
*/ |
| |
|
| #define DEBUG |
/* #define DEBUG */ |
| #undef DEBUG |
|
| #include <stdio.h> |
#include <stdio.h> |
| #include "gc_priv.h" |
#include "private/gc_priv.h" |
| |
|
| |
GC_bool GC_use_entire_heap = 0; |
| |
|
| /* |
/* |
| * Free heap blocks are kept on one of several free lists, |
* Free heap blocks are kept on one of several free lists, |
|
|
| |
|
| struct hblk * GC_hblkfreelist[N_HBLK_FLS+1] = { 0 }; |
struct hblk * GC_hblkfreelist[N_HBLK_FLS+1] = { 0 }; |
| |
|
| |
#ifndef USE_MUNMAP |
| |
|
| |
word GC_free_bytes[N_HBLK_FLS+1] = { 0 }; |
| |
/* Number of free bytes on each list. */ |
| |
|
| |
/* Is bytes + the number of free bytes on lists n .. N_HBLK_FLS */ |
| |
/* > GC_max_large_allocd_bytes? */ |
| |
# ifdef __GNUC__ |
| |
__inline__ |
| |
# endif |
| |
static GC_bool GC_enough_large_bytes_left(bytes,n) |
| |
word bytes; |
| |
int n; |
| |
{ |
| |
int i; |
| |
for (i = N_HBLK_FLS; i >= n; --i) { |
| |
bytes += GC_free_bytes[i]; |
| |
if (bytes > GC_max_large_allocd_bytes) return TRUE; |
| |
} |
| |
return FALSE; |
| |
} |
| |
|
| |
# define INCR_FREE_BYTES(n, b) GC_free_bytes[n] += (b); |
| |
|
| |
# define FREE_ASSERT(e) GC_ASSERT(e) |
| |
|
| |
#else /* USE_MUNMAP */ |
| |
|
| |
# define INCR_FREE_BYTES(n, b) |
| |
# define FREE_ASSERT(e) |
| |
|
| |
#endif /* USE_MUNMAP */ |
| |
|
| /* Map a number of blocks to the appropriate large block free list index. */ |
/* Map a number of blocks to the appropriate large block free list index. */ |
| int GC_hblk_fl_from_blocks(blocks_needed) |
int GC_hblk_fl_from_blocks(blocks_needed) |
| word blocks_needed; |
word blocks_needed; |
| Line 57 word blocks_needed; |
|
| Line 90 word blocks_needed; |
|
| |
|
| } |
} |
| |
|
| # define HBLK_IS_FREE(hdr) ((hdr) -> hb_map == GC_invalid_map) |
|
| # define PHDR(hhdr) HDR(hhdr -> hb_prev) |
# define PHDR(hhdr) HDR(hhdr -> hb_prev) |
| # define NHDR(hhdr) HDR(hhdr -> hb_next) |
# define NHDR(hhdr) HDR(hhdr -> hb_next) |
| |
|
| Line 78 void GC_print_hblkfreelist() |
|
| Line 110 void GC_print_hblkfreelist() |
|
| |
|
| for (i = 0; i <= N_HBLK_FLS; ++i) { |
for (i = 0; i <= N_HBLK_FLS; ++i) { |
| h = GC_hblkfreelist[i]; |
h = GC_hblkfreelist[i]; |
| if (0 != h) GC_printf1("Free list %ld:\n", (unsigned long)i); |
# ifdef USE_MUNMAP |
| |
if (0 != h) GC_printf1("Free list %ld (Total size %ld):\n", |
| |
(unsigned long)i); |
| |
# else |
| |
if (0 != h) GC_printf2("Free list %ld (Total size %ld):\n", |
| |
(unsigned long)i, |
| |
(unsigned long)GC_free_bytes[i]); |
| |
# endif |
| while (h != 0) { |
while (h != 0) { |
| hhdr = HDR(h); |
hhdr = HDR(h); |
| sz = hhdr -> hb_sz; |
sz = hhdr -> hb_sz; |
| Line 218 void GC_remove_from_fl(hhdr, n) |
|
| Line 257 void GC_remove_from_fl(hhdr, n) |
|
| hdr * hhdr; |
hdr * hhdr; |
| int n; |
int n; |
| { |
{ |
| |
int index; |
| |
|
| GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0); |
GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0); |
| |
# ifndef USE_MUNMAP |
| |
/* We always need index to mainatin free counts. */ |
| |
if (FL_UNKNOWN == n) { |
| |
index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz)); |
| |
} else { |
| |
index = n; |
| |
} |
| |
# endif |
| if (hhdr -> hb_prev == 0) { |
if (hhdr -> hb_prev == 0) { |
| int index; |
# ifdef USE_MUNMAP |
| if (FL_UNKNOWN == n) { |
if (FL_UNKNOWN == n) { |
| index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz)); |
index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz)); |
| } else { |
} else { |
| index = n; |
index = n; |
| } |
} |
| |
# endif |
| GC_ASSERT(HDR(GC_hblkfreelist[index]) == hhdr); |
GC_ASSERT(HDR(GC_hblkfreelist[index]) == hhdr); |
| GC_hblkfreelist[index] = hhdr -> hb_next; |
GC_hblkfreelist[index] = hhdr -> hb_next; |
| } else { |
} else { |
| PHDR(hhdr) -> hb_next = hhdr -> hb_next; |
hdr *phdr; |
| |
GET_HDR(hhdr -> hb_prev, phdr); |
| |
phdr -> hb_next = hhdr -> hb_next; |
| } |
} |
| |
INCR_FREE_BYTES(index, - (signed_word)(hhdr -> hb_sz)); |
| |
FREE_ASSERT(GC_free_bytes[index] >= 0); |
| if (0 != hhdr -> hb_next) { |
if (0 != hhdr -> hb_next) { |
| |
hdr * nhdr; |
| GC_ASSERT(!IS_FORWARDING_ADDR_OR_NIL(NHDR(hhdr))); |
GC_ASSERT(!IS_FORWARDING_ADDR_OR_NIL(NHDR(hhdr))); |
| NHDR(hhdr) -> hb_prev = hhdr -> hb_prev; |
GET_HDR(hhdr -> hb_next, nhdr); |
| |
nhdr -> hb_prev = hhdr -> hb_prev; |
| } |
} |
| } |
} |
| |
|
| Line 244 struct hblk * GC_free_block_ending_at(h) |
|
| Line 300 struct hblk * GC_free_block_ending_at(h) |
|
| struct hblk *h; |
struct hblk *h; |
| { |
{ |
| struct hblk * p = h - 1; |
struct hblk * p = h - 1; |
| hdr * phdr = HDR(p); |
hdr * phdr; |
| |
|
| |
GET_HDR(p, phdr); |
| while (0 != phdr && IS_FORWARDING_ADDR_OR_NIL(phdr)) { |
while (0 != phdr && IS_FORWARDING_ADDR_OR_NIL(phdr)) { |
| p = FORWARDED_ADDR(p,phdr); |
p = FORWARDED_ADDR(p,phdr); |
| phdr = HDR(p); |
phdr = HDR(p); |
| } |
} |
| if (0 != phdr && HBLK_IS_FREE(phdr)) return p; |
if (0 != phdr) { |
| |
if(HBLK_IS_FREE(phdr)) { |
| |
return p; |
| |
} else { |
| |
return 0; |
| |
} |
| |
} |
| p = GC_prev_block(h - 1); |
p = GC_prev_block(h - 1); |
| if (0 != p) { |
if (0 != p) { |
| phdr = HDR(p); |
phdr = HDR(p); |
|
|
| { |
{ |
| int index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz)); |
int index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz)); |
| struct hblk *second = GC_hblkfreelist[index]; |
struct hblk *second = GC_hblkfreelist[index]; |
| |
hdr * second_hdr; |
| # ifdef GC_ASSERTIONS |
# ifdef GC_ASSERTIONS |
| struct hblk *next = (struct hblk *)((word)h + hhdr -> hb_sz); |
struct hblk *next = (struct hblk *)((word)h + hhdr -> hb_sz); |
| hdr * nexthdr = HDR(next); |
hdr * nexthdr = HDR(next); |
|
|
| # endif |
# endif |
| GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0); |
GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0); |
| GC_hblkfreelist[index] = h; |
GC_hblkfreelist[index] = h; |
| |
INCR_FREE_BYTES(index, hhdr -> hb_sz); |
| |
FREE_ASSERT(GC_free_bytes[index] <= GC_large_free_bytes) |
| hhdr -> hb_next = second; |
hhdr -> hb_next = second; |
| hhdr -> hb_prev = 0; |
hhdr -> hb_prev = 0; |
| if (0 != second) HDR(second) -> hb_prev = h; |
if (0 != second) { |
| |
GET_HDR(second, second_hdr); |
| |
second_hdr -> hb_prev = h; |
| |
} |
| GC_invalidate_map(hhdr); |
GC_invalidate_map(hhdr); |
| } |
} |
| |
|
| Line 330 void GC_merge_unmapped(void) |
|
| Line 399 void GC_merge_unmapped(void) |
|
| for (i = 0; i <= N_HBLK_FLS; ++i) { |
for (i = 0; i <= N_HBLK_FLS; ++i) { |
| h = GC_hblkfreelist[i]; |
h = GC_hblkfreelist[i]; |
| while (h != 0) { |
while (h != 0) { |
| hhdr = HDR(h); |
GET_HDR(h, hhdr); |
| size = hhdr->hb_sz; |
size = hhdr->hb_sz; |
| next = (struct hblk *)((word)h + size); |
next = (struct hblk *)((word)h + size); |
| nexthdr = HDR(next); |
GET_HDR(next, nexthdr); |
| /* Coalesce with successor, if possible */ |
/* Coalesce with successor, if possible */ |
| if (0 != nexthdr && HBLK_IS_FREE(nexthdr)) { |
if (0 != nexthdr && HBLK_IS_FREE(nexthdr)) { |
| nextsize = nexthdr -> hb_sz; |
nextsize = nexthdr -> hb_sz; |
|
|
| GC_remove_from_fl(hhdr, index); |
GC_remove_from_fl(hhdr, index); |
| if (total_size == bytes) return h; |
if (total_size == bytes) return h; |
| rest = (struct hblk *)((word)h + bytes); |
rest = (struct hblk *)((word)h + bytes); |
| if (!GC_install_header(rest)) return(0); |
rest_hdr = GC_install_header(rest); |
| rest_hdr = HDR(rest); |
if (0 == rest_hdr) return(0); |
| rest_hdr -> hb_sz = total_size - bytes; |
rest_hdr -> hb_sz = total_size - bytes; |
| rest_hdr -> hb_flags = 0; |
rest_hdr -> hb_flags = 0; |
| # ifdef GC_ASSERTIONS |
# ifdef GC_ASSERTIONS |
| // Mark h not free, to avoid assertion about adjacent free blocks. |
/* Mark h not free, to avoid assertion about adjacent free blocks. */ |
| hhdr -> hb_map = 0; |
hhdr -> hb_map = 0; |
| # endif |
# endif |
| GC_add_to_fl(rest, rest_hdr); |
GC_add_to_fl(rest, rest_hdr); |
| Line 447 int index; /* Index of free list */ |
|
| Line 516 int index; /* Index of free list */ |
|
| if (0 != next) { |
if (0 != next) { |
| HDR(next) -> hb_prev = n; |
HDR(next) -> hb_prev = n; |
| } |
} |
| |
INCR_FREE_BYTES(index, -(signed_word)h_size); |
| |
FREE_ASSERT(GC_free_bytes[index] > 0); |
| # ifdef GC_ASSERTIONS |
# ifdef GC_ASSERTIONS |
| nhdr -> hb_map = 0; /* Don't fail test for consecutive */ |
nhdr -> hb_map = 0; /* Don't fail test for consecutive */ |
| /* free blocks in GC_add_to_fl. */ |
/* free blocks in GC_add_to_fl. */ |
| Line 468 struct hblk * GC_allochblk_nth(); |
|
| Line 539 struct hblk * GC_allochblk_nth(); |
|
| * NOTE: We set obj_map field in header correctly. |
* NOTE: We set obj_map field in header correctly. |
| * Caller is responsible for building an object freelist in block. |
* Caller is responsible for building an object freelist in block. |
| * |
* |
| * We clear the block if it is destined for large objects, and if |
* Unlike older versions of the collectors, the client is responsible |
| * kind requires that newly allocated objects be cleared. |
* for clearing the block, if necessary. |
| */ |
*/ |
| struct hblk * |
struct hblk * |
| GC_allochblk(sz, kind, flags) |
GC_allochblk(sz, kind, flags) |
| word sz; |
word sz; |
| int kind; |
int kind; |
| unsigned char flags; /* IGNORE_OFF_PAGE or 0 */ |
unsigned flags; /* IGNORE_OFF_PAGE or 0 */ |
| { |
{ |
| int start_list = GC_hblk_fl_from_blocks(OBJ_SZ_TO_BLOCKS(sz)); |
word blocks = OBJ_SZ_TO_BLOCKS(sz); |
| |
int start_list = GC_hblk_fl_from_blocks(blocks); |
| int i; |
int i; |
| for (i = start_list; i <= N_HBLK_FLS; ++i) { |
for (i = start_list; i <= N_HBLK_FLS; ++i) { |
| struct hblk * result = GC_allochblk_nth(sz, kind, flags, i); |
struct hblk * result = GC_allochblk_nth(sz, kind, flags, i); |
| if (0 != result) return result; |
if (0 != result) { |
| |
return result; |
| |
} |
| } |
} |
| return 0; |
return 0; |
| } |
} |
|
|
| |
|
| /* search for a big enough block in free list */ |
/* search for a big enough block in free list */ |
| hbp = GC_hblkfreelist[n]; |
hbp = GC_hblkfreelist[n]; |
| hhdr = HDR(hbp); |
for(; 0 != hbp; hbp = hhdr -> hb_next) { |
| for(; 0 != hbp; hbp = hhdr -> hb_next, hhdr = HDR(hbp)) { |
GET_HDR(hbp, hhdr); |
| size_avail = hhdr->hb_sz; |
size_avail = hhdr->hb_sz; |
| if (size_avail < size_needed) continue; |
if (size_avail < size_needed) continue; |
| # ifdef PRESERVE_LAST |
if (!GC_use_entire_heap |
| if (size_avail != size_needed |
&& size_avail != size_needed |
| && !GC_incremental && GC_should_collect()) { |
&& USED_HEAP_SIZE >= GC_requested_heapsize |
| |
&& !TRUE_INCREMENTAL && GC_should_collect()) { |
| |
# ifdef USE_MUNMAP |
| continue; |
continue; |
| } |
# else |
| # endif |
/* If we have enough large blocks left to cover any */ |
| |
/* previous request for large blocks, we go ahead */ |
| |
/* and split. Assuming a steady state, that should */ |
| |
/* be safe. It means that we can use the full */ |
| |
/* heap if we allocate only small objects. */ |
| |
if (!GC_enough_large_bytes_left(GC_large_allocd_bytes, n)) { |
| |
continue; |
| |
} |
| |
/* If we are deallocating lots of memory from */ |
| |
/* finalizers, fail and collect sooner rather */ |
| |
/* than later. */ |
| |
if (GC_finalizer_mem_freed > (GC_heapsize >> 4)) { |
| |
continue; |
| |
} |
| |
# endif /* !USE_MUNMAP */ |
| |
} |
| /* If the next heap block is obviously better, go on. */ |
/* If the next heap block is obviously better, go on. */ |
| /* This prevents us from disassembling a single large block */ |
/* This prevents us from disassembling a single large block */ |
| /* to get tiny blocks. */ |
/* to get tiny blocks. */ |
|
|
| |
|
| thishbp = hhdr -> hb_next; |
thishbp = hhdr -> hb_next; |
| if (thishbp != 0) { |
if (thishbp != 0) { |
| thishdr = HDR(thishbp); |
GET_HDR(thishbp, thishdr); |
| next_size = (signed_word)(thishdr -> hb_sz); |
next_size = (signed_word)(thishdr -> hb_sz); |
| if (next_size < size_avail |
if (next_size < size_avail |
| && next_size >= size_needed |
&& next_size >= size_needed |
|
|
| |
|
| while ((ptr_t)lasthbp <= search_end |
while ((ptr_t)lasthbp <= search_end |
| && (thishbp = GC_is_black_listed(lasthbp, |
&& (thishbp = GC_is_black_listed(lasthbp, |
| (word)eff_size_needed))) { |
(word)eff_size_needed)) |
| |
!= 0) { |
| lasthbp = thishbp; |
lasthbp = thishbp; |
| } |
} |
| size_avail -= (ptr_t)lasthbp - (ptr_t)hbp; |
size_avail -= (ptr_t)lasthbp - (ptr_t)hbp; |
| thishbp = lasthbp; |
thishbp = lasthbp; |
| if (size_avail >= size_needed) { |
if (size_avail >= size_needed) { |
| if (thishbp != hbp && GC_install_header(thishbp)) { |
if (thishbp != hbp && |
| |
0 != (thishdr = GC_install_header(thishbp))) { |
| /* Make sure it's mapped before we mangle it. */ |
/* Make sure it's mapped before we mangle it. */ |
| # ifdef USE_MUNMAP |
# ifdef USE_MUNMAP |
| if (!IS_MAPPED(hhdr)) { |
if (!IS_MAPPED(hhdr)) { |
| GC_remap((ptr_t)hbp, size_avail); |
GC_remap((ptr_t)hbp, hhdr -> hb_sz); |
| hhdr -> hb_flags &= ~WAS_UNMAPPED; |
hhdr -> hb_flags &= ~WAS_UNMAPPED; |
| } |
} |
| # endif |
# endif |
| /* Split the block at thishbp */ |
/* Split the block at thishbp */ |
| thishdr = HDR(thishbp); |
|
| GC_split_block(hbp, hhdr, thishbp, thishdr, n); |
GC_split_block(hbp, hhdr, thishbp, thishdr, n); |
| /* Advance to thishbp */ |
/* Advance to thishbp */ |
| hbp = thishbp; |
hbp = thishbp; |
|
|
| && orig_avail - size_needed |
&& orig_avail - size_needed |
| > (signed_word)BL_LIMIT) { |
> (signed_word)BL_LIMIT) { |
| /* Punt, since anything else risks unreasonable heap growth. */ |
/* Punt, since anything else risks unreasonable heap growth. */ |
| WARN("Needed to allocate blacklisted block at 0x%lx\n", |
if (++GC_large_alloc_warn_suppressed |
| (word)hbp); |
>= GC_large_alloc_warn_interval) { |
| |
WARN("Repeated allocation of very large block " |
| |
"(appr. size %ld):\n" |
| |
"\tMay lead to memory leak and poor performance.\n", |
| |
size_needed); |
| |
GC_large_alloc_warn_suppressed = 0; |
| |
} |
| size_avail = orig_avail; |
size_avail = orig_avail; |
| } else if (size_avail == 0 && size_needed == HBLKSIZE |
} else if (size_avail == 0 && size_needed == HBLKSIZE |
| && IS_MAPPED(hhdr)) { |
&& IS_MAPPED(hhdr)) { |
|
|
| GC_large_free_bytes -= total_size; |
GC_large_free_bytes -= total_size; |
| GC_remove_from_fl(hhdr, n); |
GC_remove_from_fl(hhdr, n); |
| for (h = hbp; h < limit; h++) { |
for (h = hbp; h < limit; h++) { |
| if (h == hbp || GC_install_header(h)) { |
if (h == hbp || 0 != (hhdr = GC_install_header(h))) { |
| hhdr = HDR(h); |
|
| (void) setup_header( |
(void) setup_header( |
| hhdr, |
hhdr, |
| BYTES_TO_WORDS(HBLKSIZE - HDR_BYTES), |
BYTES_TO_WORDS(HBLKSIZE), |
| PTRFREE, 0); /* Cant fail */ |
PTRFREE, 0); /* Cant fail */ |
| if (GC_debugging_started) { |
if (GC_debugging_started) { |
| BZERO(h + HDR_BYTES, HBLKSIZE - HDR_BYTES); |
BZERO(h, HBLKSIZE); |
| } |
} |
| } |
} |
| } |
} |
|
|
| if( size_avail >= size_needed ) { |
if( size_avail >= size_needed ) { |
| # ifdef USE_MUNMAP |
# ifdef USE_MUNMAP |
| if (!IS_MAPPED(hhdr)) { |
if (!IS_MAPPED(hhdr)) { |
| GC_remap((ptr_t)hbp, size_avail); |
GC_remap((ptr_t)hbp, hhdr -> hb_sz); |
| hhdr -> hb_flags &= ~WAS_UNMAPPED; |
hhdr -> hb_flags &= ~WAS_UNMAPPED; |
| } |
} |
| # endif |
# endif |
|
|
| |
|
| if (0 == hbp) return 0; |
if (0 == hbp) return 0; |
| |
|
| /* Notify virtual dirty bit implementation that we are about to write. */ |
|
| GC_write_hint(hbp); |
|
| |
|
| /* Add it to map of valid blocks */ |
/* Add it to map of valid blocks */ |
| if (!GC_install_counts(hbp, (word)size_needed)) return(0); |
if (!GC_install_counts(hbp, (word)size_needed)) return(0); |
| /* This leaks memory under very rare conditions. */ |
/* This leaks memory under very rare conditions. */ |
|
|
| GC_remove_counts(hbp, (word)size_needed); |
GC_remove_counts(hbp, (word)size_needed); |
| return(0); /* ditto */ |
return(0); /* ditto */ |
| } |
} |
| |
|
| /* Clear block if necessary */ |
|
| if (GC_debugging_started |
|
| || sz > MAXOBJSZ && GC_obj_kinds[kind].ok_init) { |
|
| BZERO(hbp + HDR_BYTES, size_needed - HDR_BYTES); |
|
| } |
|
| |
|
| |
/* Notify virtual dirty bit implementation that we are about to write. */ |
| |
/* Ensure that pointerfree objects are not protected if it's avoidable. */ |
| |
GC_remove_protection(hbp, divHBLKSZ(size_needed), |
| |
(hhdr -> hb_descr == 0) /* pointer-free */); |
| |
|
| /* We just successfully allocated a block. Restart count of */ |
/* We just successfully allocated a block. Restart count of */ |
| /* consecutive failures. */ |
/* consecutive failures. */ |
| { |
{ |
| Line 686 hdr *hhdr, *prevhdr, *nexthdr; |
|
| Line 779 hdr *hhdr, *prevhdr, *nexthdr; |
|
| signed_word size; |
signed_word size; |
| |
|
| |
|
| hhdr = HDR(hbp); |
GET_HDR(hbp, hhdr); |
| size = hhdr->hb_sz; |
size = hhdr->hb_sz; |
| size = HBLKSIZE * OBJ_SZ_TO_BLOCKS(size); |
size = HBLKSIZE * OBJ_SZ_TO_BLOCKS(size); |
| GC_remove_counts(hbp, (word)size); |
GC_remove_counts(hbp, (word)size); |
| Line 696 signed_word size; |
|
| Line 789 signed_word size; |
|
| if (HBLK_IS_FREE(hhdr)) { |
if (HBLK_IS_FREE(hhdr)) { |
| GC_printf1("Duplicate large block deallocation of 0x%lx\n", |
GC_printf1("Duplicate large block deallocation of 0x%lx\n", |
| (unsigned long) hbp); |
(unsigned long) hbp); |
| |
ABORT("Duplicate large block deallocation"); |
| } |
} |
| |
|
| GC_ASSERT(IS_MAPPED(hhdr)); |
GC_ASSERT(IS_MAPPED(hhdr)); |
| GC_invalidate_map(hhdr); |
GC_invalidate_map(hhdr); |
| next = (struct hblk *)((word)hbp + size); |
next = (struct hblk *)((word)hbp + size); |
| nexthdr = HDR(next); |
GET_HDR(next, nexthdr); |
| prev = GC_free_block_ending_at(hbp); |
prev = GC_free_block_ending_at(hbp); |
| /* Coalesce with successor, if possible */ |
/* Coalesce with successor, if possible */ |
| if(0 != nexthdr && HBLK_IS_FREE(nexthdr) && IS_MAPPED(nexthdr)) { |
if(0 != nexthdr && HBLK_IS_FREE(nexthdr) && IS_MAPPED(nexthdr)) { |