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Diffstat (limited to 'boehm-gc/alloc.c')
| -rw-r--r-- | boehm-gc/alloc.c | 849 |
1 files changed, 849 insertions, 0 deletions
diff --git a/boehm-gc/alloc.c b/boehm-gc/alloc.c new file mode 100644 index 0000000..d60544a --- /dev/null +++ b/boehm-gc/alloc.c @@ -0,0 +1,849 @@ +/* + * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers + * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved. + * + * 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. + * + */ +/* Boehm, February 16, 1996 2:26 pm PST */ + + +# include "gc_priv.h" + +# include <stdio.h> +# ifndef MACOS +# include <signal.h> +# include <sys/types.h> +# endif + +/* + * Separate free lists are maintained for different sized objects + * up to MAXOBJSZ. + * 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 i as follows: + * + * opp = &(GC_objfreelist[i]); + * if (*opp == 0) GC_allocobj(i, NORMAL); + * ptr = *opp; + * *opp = obj_link(ptr); + * + * 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; + +int GC_incremental = 0; /* By default, stop the world. */ + +int GC_full_freq = 4; /* Every 5th collection is a full */ + /* collection. */ + +char * GC_copyright[] = +{"Copyright 1988,1989 Hans-J. Boehm and Alan J. Demers ", +"Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. ", +"Copyright (c) 1996-1997 by Silicon Graphics. All rights reserved. ", +"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." }; + +# include "version.h" + +/* some more variables */ + +extern signed_word GC_mem_found; /* Number of reclaimed longwords */ + /* after garbage collection */ + +GC_bool GC_dont_expand = 0; + +word GC_free_space_divisor = 4; + +extern GC_bool GC_collection_in_progress(); + +int GC_never_stop_func GC_PROTO((void)) { return(0); } + +CLOCK_TYPE GC_start_time; + +int GC_timeout_stop_func GC_PROTO((void)) +{ + CLOCK_TYPE current_time; + static unsigned count = 0; + unsigned long time_diff; + + if ((count++ & 3) != 0) return(0); + GET_TIME(current_time); + time_diff = MS_TIME_DIFF(current_time,GC_start_time); + if (time_diff >= TIME_LIMIT) { +# ifdef PRINTSTATS + GC_printf0("Abandoning stopped marking after "); + GC_printf1("%lu msecs\n", (unsigned long)time_diff); +# endif + return(1); + } + return(0); +} + +/* Return the minimum number of words that must be allocated between */ +/* collections to amortize the collection cost. */ +static word min_words_allocd() +{ +# ifdef THREADS + /* We punt, for now. */ + register signed_word stack_size = 10000; +# else + int dummy; + register signed_word stack_size = (ptr_t)(&dummy) - GC_stackbottom; +# endif + register word total_root_size; /* includes double stack size, */ + /* since the stack is expensive */ + /* to scan. */ + + if (stack_size < 0) stack_size = -stack_size; + total_root_size = 2 * stack_size + GC_root_size; + if (GC_incremental) { + return(BYTES_TO_WORDS(GC_heapsize + total_root_size) + / (2 * GC_free_space_divisor)); + } else { + return(BYTES_TO_WORDS(GC_heapsize + total_root_size) + / GC_free_space_divisor); + } +} + +/* Return the number of words allocated, adjusted for explicit storage */ +/* management, etc.. This number is used in deciding when to trigger */ +/* collections. */ +word GC_adj_words_allocd() +{ + register signed_word result; + register signed_word expl_managed = + BYTES_TO_WORDS((long)GC_non_gc_bytes + - (long)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_words_allocd + - (signed_word)GC_mem_freed - expl_managed; + if (result > (signed_word)GC_words_allocd) { + result = GC_words_allocd; + /* probably client bug or unfortunate scheduling */ + } + result += GC_words_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. */ + result += GC_words_wasted; + /* This doesn't reflect useful work. But if there is lots of */ + /* new fragmentation, the same is probably true of the heap, */ + /* and the collection will be correspondingly cheaper. */ + if (result < (signed_word)(GC_words_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_words_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 garbade 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. */ +void GC_clear_a_few_frames() +{ +# define NWORDS 64 + word frames[NWORDS]; + register int i; + + for (i = 0; i < NWORDS; i++) frames[i] = 0; +} + +/* Have we allocated enough to amortize a collection? */ +GC_bool GC_should_collect() +{ + return(GC_adj_words_allocd() >= min_words_allocd()); +} + +void GC_notify_full_gc() +{ + if (GC_start_call_back != (void (*)())0) { + (*GC_start_call_back)(); + } +} + +/* + * Initiate a garbage collection if appropriate. + * Choose judiciously + * between partial, full, and stop-world collections. + * Assumes lock held, signals disabled. + */ +void GC_maybe_gc() +{ + static int n_partial_gcs = 0; + if (GC_should_collect()) { + if (!GC_incremental) { + GC_notify_full_gc(); + GC_gcollect_inner(); + n_partial_gcs = 0; + return; + } else if (n_partial_gcs >= GC_full_freq) { +# ifdef PRINTSTATS + GC_printf2( + "***>Full mark for collection %lu after %ld allocd bytes\n", + (unsigned long) GC_gc_no+1, + (long)WORDS_TO_BYTES(GC_words_allocd)); +# endif + GC_promote_black_lists(); + (void)GC_reclaim_all((GC_stop_func)0, TRUE); + GC_clear_marks(); + n_partial_gcs = 0; + GC_notify_full_gc(); + } else { + n_partial_gcs++; + } + /* We try to mark with the world stopped. */ + /* If we run out of time, this turns into */ + /* incremental marking. */ + GET_TIME(GC_start_time); + if (GC_stopped_mark(GC_timeout_stop_func)) { +# ifdef SAVE_CALL_CHAIN + GC_save_callers(GC_last_stack); +# endif + GC_finish_collection(); + } + } +} + + +/* + * Stop the world garbage collection. Assumes lock held, signals disabled. + * If stop_func is not GC_never_stop_func, then abort if stop_func returns TRUE. + */ +GC_bool GC_try_to_collect_inner(stop_func) +GC_stop_func stop_func; +{ + if (GC_collection_in_progress()) { +# ifdef PRINTSTATS + GC_printf0( + "GC_try_to_collect_inner: finishing collection in progress\n"); +# endif /* PRINTSTATS */ + /* Just finish collection already in progress. */ + while(GC_collection_in_progress()) { + if (stop_func()) return(FALSE); + GC_collect_a_little_inner(1); + } + } +# ifdef PRINTSTATS + GC_printf2( + "Initiating full world-stop collection %lu after %ld allocd bytes\n", + (unsigned long) GC_gc_no+1, + (long)WORDS_TO_BYTES(GC_words_allocd)); +# 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. */ + if (stop_func != GC_never_stop_func + && !GC_reclaim_all(stop_func, FALSE)) { + /* Aborted. So far everything is still consistent. */ + return(FALSE); + } + GC_invalidate_mark_state(); /* Flush mark stack. */ + GC_clear_marks(); +# ifdef SAVE_CALL_CHAIN + GC_save_callers(GC_last_stack); +# endif + 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. */ + return(FALSE); + } + GC_finish_collection(); + return(TRUE); +} + + + +/* + * Perform n units of garbage collection work. A unit is intended to touch + * roughly a GC_RATE pages. Every once in a while, we do more than that. + */ +# define GC_RATE 8 + +int GC_deficit = 0; /* The number of extra calls to GC_mark_some */ + /* that we have made. */ + /* Negative values are equivalent to 0. */ + +void GC_collect_a_little_inner(n) +int n; +{ + register int i; + + if (GC_collection_in_progress()) { + for (i = GC_deficit; i < GC_RATE*n; i++) { + if (GC_mark_some()) { + /* Need to finish a collection */ +# ifdef SAVE_CALL_CHAIN + GC_save_callers(GC_last_stack); +# endif + (void) GC_stopped_mark(GC_never_stop_func); + GC_finish_collection(); + break; + } + } + if (GC_deficit > 0) GC_deficit -= GC_RATE*n; + } else { + GC_maybe_gc(); + } +} + +int GC_collect_a_little GC_PROTO(()) +{ + int result; + DCL_LOCK_STATE; + + DISABLE_SIGNALS(); + LOCK(); + GC_collect_a_little_inner(1); + result = (int)GC_collection_in_progress(); + UNLOCK(); + ENABLE_SIGNALS(); + return(result); +} + +/* + * Assumes lock is held, signals are disabled. + * We stop the world. + * If final is TRUE, then we finish the collection, no matter how long + * it takes. + * Otherwise we may fail and return FALSE if this takes too long. + * Increment GC_gc_no if we succeed. + */ +GC_bool GC_stopped_mark(stop_func) +GC_stop_func stop_func; +{ + register int i; +# ifdef PRINTSTATS + CLOCK_TYPE start_time, current_time; +# endif + + STOP_WORLD(); +# ifdef PRINTSTATS + GET_TIME(start_time); + GC_printf1("--> Marking for collection %lu ", + (unsigned long) GC_gc_no + 1); + GC_printf2("after %lu allocd bytes + %lu wasted bytes\n", + (unsigned long) WORDS_TO_BYTES(GC_words_allocd), + (unsigned long) WORDS_TO_BYTES(GC_words_wasted)); +# endif + + /* Mark from all roots. */ + /* Minimize junk left in my registers and on the stack */ + GC_clear_a_few_frames(); + GC_noop(0,0,0,0,0,0); + GC_initiate_gc(); + for(i = 0;;i++) { + if ((*stop_func)()) { +# ifdef PRINTSTATS + GC_printf0("Abandoned stopped marking after "); + GC_printf1("%lu iterations\n", + (unsigned long)i); +# endif + GC_deficit = i; /* Give the mutator a chance. */ + START_WORLD(); + return(FALSE); + } + if (GC_mark_some()) break; + } + + GC_gc_no++; +# ifdef PRINTSTATS + GC_printf2("Collection %lu reclaimed %ld bytes", + (unsigned long) GC_gc_no - 1, + (long)WORDS_TO_BYTES(GC_mem_found)); + GC_printf1(" ---> heapsize = %lu bytes\n", + (unsigned long) GC_heapsize); + /* Printf arguments may be pushed in funny places. Clear the */ + /* space. */ + GC_printf0(""); +# endif + + /* Check all debugged objects for consistency */ + if (GC_debugging_started) { + (*GC_check_heap)(); + } + +# ifdef PRINTTIMES + GET_TIME(current_time); + GC_printf1("World-stopped marking took %lu msecs\n", + MS_TIME_DIFF(current_time,start_time)); +# endif + START_WORLD(); + return(TRUE); +} + + +/* Finish up a collection. Assumes lock is held, signals are disabled, */ +/* but the world is otherwise running. */ +void GC_finish_collection() +{ +# ifdef PRINTTIMES + CLOCK_TYPE start_time; + CLOCK_TYPE finalize_time; + CLOCK_TYPE done_time; + + GET_TIME(start_time); + finalize_time = start_time; +# endif + +# ifdef GATHERSTATS + GC_mem_found = 0; +# endif +# ifdef FIND_LEAK + /* Mark all objects on the free list. All objects should be */ + /* marked when we're done. */ + { + register word size; /* current object size */ + register ptr_t p; /* pointer to current object */ + register struct hblk * h; /* pointer to block containing *p */ + register hdr * hhdr; + register int word_no; /* "index" of *p in *q */ + int kind; + + for (kind = 0; kind < GC_n_kinds; kind++) { + for (size = 1; size <= MAXOBJSZ; size++) { + for (p= GC_obj_kinds[kind].ok_freelist[size]; + p != 0; p=obj_link(p)){ + h = HBLKPTR(p); + hhdr = HDR(h); + word_no = (((word *)p) - ((word *)h)); + set_mark_bit_from_hdr(hhdr, word_no); + } + } + } + } + /* Check that everything is marked */ + GC_start_reclaim(TRUE); +# else + + GC_finalize(); +# ifdef STUBBORN_ALLOC + GC_clean_changing_list(); +# endif + +# ifdef PRINTTIMES + GET_TIME(finalize_time); +# endif + + /* Clear free list mark bits, in case they got accidentally marked */ + /* Note: HBLKPTR(p) == pointer to head of block containing *p */ + /* Also subtract memory remaining from GC_mem_found count. */ + /* Note that composite objects on free list are cleared. */ + /* Thus accidentally marking a free list is not a problem; only */ + /* objects on the list itself will be marked, and that's fixed here. */ + { + register word size; /* current object size */ + register ptr_t p; /* pointer to current object */ + register struct hblk * h; /* pointer to block containing *p */ + register hdr * hhdr; + register int word_no; /* "index" of *p in *q */ + int kind; + + for (kind = 0; kind < GC_n_kinds; kind++) { + for (size = 1; size <= MAXOBJSZ; size++) { + for (p= GC_obj_kinds[kind].ok_freelist[size]; + p != 0; p=obj_link(p)){ + h = HBLKPTR(p); + hhdr = HDR(h); + word_no = (((word *)p) - ((word *)h)); + clear_mark_bit_from_hdr(hhdr, word_no); +# ifdef GATHERSTATS + GC_mem_found -= size; +# endif + } + } + } + } + + +# ifdef PRINTSTATS + GC_printf1("Bytes recovered before sweep - f.l. count = %ld\n", + (long)WORDS_TO_BYTES(GC_mem_found)); +# endif + + /* Reconstruct free lists to contain everything not marked */ + GC_start_reclaim(FALSE); + +# endif /* !FIND_LEAK */ + +# ifdef PRINTSTATS + GC_printf2( + "Immediately reclaimed %ld bytes in heap of size %lu bytes\n", + (long)WORDS_TO_BYTES(GC_mem_found), + (unsigned long)GC_heapsize); + GC_printf2("%lu (atomic) + %lu (composite) collectable bytes in use\n", + (unsigned long)WORDS_TO_BYTES(GC_atomic_in_use), + (unsigned long)WORDS_TO_BYTES(GC_composite_in_use)); +# endif + + /* Reset or increment counters for next cycle */ + GC_words_allocd_before_gc += GC_words_allocd; + GC_non_gc_bytes_at_gc = GC_non_gc_bytes; + GC_words_allocd = 0; + GC_words_wasted = 0; + GC_mem_freed = 0; + +# ifdef PRINTTIMES + GET_TIME(done_time); + GC_printf2("Finalize + initiate sweep took %lu + %lu msecs\n", + MS_TIME_DIFF(finalize_time,start_time), + MS_TIME_DIFF(done_time,finalize_time)); +# endif +} + +/* Externally callable routine to invoke full, stop-world collection */ +# if defined(__STDC__) || defined(__cplusplus) + int GC_try_to_collect(GC_stop_func stop_func) +# else + int GC_try_to_collect(stop_func) + GC_stop_func stop_func; +# endif +{ + int result; + DCL_LOCK_STATE; + + GC_INVOKE_FINALIZERS(); + DISABLE_SIGNALS(); + LOCK(); + ENTER_GC(); + if (!GC_is_initialized) GC_init_inner(); + /* Minimize junk left in my registers */ + GC_noop(0,0,0,0,0,0); + result = (int)GC_try_to_collect_inner(stop_func); + EXIT_GC(); + UNLOCK(); + ENABLE_SIGNALS(); + if(result) GC_INVOKE_FINALIZERS(); + return(result); +} + +void GC_gcollect GC_PROTO(()) +{ + GC_notify_full_gc(); + (void)GC_try_to_collect(GC_never_stop_func); +} + +word GC_n_heap_sects = 0; /* Number of sections currently in heap. */ + +/* + * Use the chunk of memory starting at p of syze bytes as part of the heap. + * Assumes p is HBLKSIZE aligned, and bytes is a multiple of HBLKSIZE. + */ +void GC_add_to_heap(p, bytes) +struct hblk *p; +word bytes; +{ + word words; + + if (GC_n_heap_sects >= MAX_HEAP_SECTS) { + ABORT("Too many heap sections: Increase MAXHINCR or MAX_HEAP_SECTS"); + } + if (!GC_install_header(p)) { + /* This is extremely unlikely. Can't add it. This will */ + /* almost certainly result in a 0 return from the allocator, */ + /* which is entirely appropriate. */ + return; + } + GC_heap_sects[GC_n_heap_sects].hs_start = (ptr_t)p; + GC_heap_sects[GC_n_heap_sects].hs_bytes = bytes; + GC_n_heap_sects++; + words = BYTES_TO_WORDS(bytes - HDR_BYTES); + HDR(p) -> hb_sz = words; + GC_freehblk(p); + GC_heapsize += bytes; + if ((ptr_t)p <= GC_least_plausible_heap_addr + || GC_least_plausible_heap_addr == 0) { + GC_least_plausible_heap_addr = (ptr_t)p - sizeof(word); + /* Making it a little smaller than necessary prevents */ + /* us from getting a false hit from the variable */ + /* itself. There's some unintentional reflection */ + /* here. */ + } + if ((ptr_t)p + bytes >= GC_greatest_plausible_heap_addr) { + GC_greatest_plausible_heap_addr = (ptr_t)p + bytes; + } +} + +#ifdef PRESERVE_LAST +GC_bool GC_in_last_heap_sect(p) +ptr_t p; +{ + struct HeapSect * last_heap_sect = &(GC_heap_sects[GC_n_heap_sects-1]); + ptr_t start = last_heap_sect -> hs_start; + ptr_t end; + + if (p < start) return FALSE; + end = start + last_heap_sect -> hs_bytes; + if (p >= end) return FALSE; + return TRUE; +} +#endif + +# if !defined(NO_DEBUGGING) +void GC_print_heap_sects() +{ + register unsigned i; + + GC_printf1("Total heap size: %lu\n", (unsigned long) GC_heapsize); + for (i = 0; i < GC_n_heap_sects; i++) { + unsigned long start = (unsigned long) GC_heap_sects[i].hs_start; + unsigned long len = (unsigned long) GC_heap_sects[i].hs_bytes; + struct hblk *h; + unsigned nbl = 0; + + GC_printf3("Section %ld from 0x%lx to 0x%lx ", (unsigned long)i, + start, (unsigned long)(start + len)); + for (h = (struct hblk *)start; h < (struct hblk *)(start + len); h++) { + if (GC_is_black_listed(h, HBLKSIZE)) nbl++; + } + GC_printf2("%lu/%lu blacklisted\n", (unsigned long)nbl, + (unsigned long)(len/HBLKSIZE)); + } +} +# endif + +ptr_t GC_least_plausible_heap_addr = (ptr_t)ONES; +ptr_t GC_greatest_plausible_heap_addr = 0; + +ptr_t GC_max(x,y) +ptr_t x, y; +{ + return(x > y? x : y); +} + +ptr_t GC_min(x,y) +ptr_t x, y; +{ + return(x < y? x : y); +} + +# if defined(__STDC__) || defined(__cplusplus) + void GC_set_max_heap_size(GC_word n) +# else + void GC_set_max_heap_size(n) + GC_word n; +# endif +{ + GC_max_heapsize = n; +} + +GC_word GC_max_retries = 0; + +/* + * this explicitly increases the size of the heap. It is used + * internally, but may also be invoked from GC_expand_hp by the user. + * The argument is in units of HBLKSIZE. + * Tiny values of n are rounded up. + * Returns FALSE on failure. + */ +GC_bool GC_expand_hp_inner(n) +word n; +{ + word bytes; + struct hblk * space; + word expansion_slop; /* Number of bytes by which we expect the */ + /* heap to expand soon. */ + + if (n < MINHINCR) n = MINHINCR; + bytes = n * HBLKSIZE; + /* Make sure bytes is a multiple of GC_page_size */ + { + word mask = GC_page_size - 1; + bytes += mask; + bytes &= ~mask; + } + + if (GC_max_heapsize != 0 && GC_heapsize + bytes > GC_max_heapsize) { + /* Exceeded self-imposed limit */ + return(FALSE); + } + space = GET_MEM(bytes); + if( space == 0 ) { + return(FALSE); + } +# ifdef PRINTSTATS + GC_printf2("Increasing heap size by %lu after %lu allocated bytes\n", + (unsigned long)bytes, + (unsigned long)WORDS_TO_BYTES(GC_words_allocd)); +# ifdef UNDEFINED + GC_printf1("Root size = %lu\n", GC_root_size); + GC_print_block_list(); GC_print_hblkfreelist(); + GC_printf0("\n"); +# endif +# endif + expansion_slop = 8 * WORDS_TO_BYTES(min_words_allocd()); + if (5 * HBLKSIZE * MAXHINCR > expansion_slop) { + expansion_slop = 5 * HBLKSIZE * MAXHINCR; + } + if (GC_last_heap_addr == 0 && !((word)space & SIGNB) + || GC_last_heap_addr != 0 && GC_last_heap_addr < (ptr_t)space) { + /* Assume the heap is growing up */ + GC_greatest_plausible_heap_addr = + GC_max(GC_greatest_plausible_heap_addr, + (ptr_t)space + bytes + expansion_slop); + } else { + /* Heap is growing down */ + GC_least_plausible_heap_addr = + GC_min(GC_least_plausible_heap_addr, + (ptr_t)space - expansion_slop); + } + GC_prev_heap_addr = GC_last_heap_addr; + GC_last_heap_addr = (ptr_t)space; + GC_add_to_heap(space, bytes); + return(TRUE); +} + +/* Really returns a bool, but it's externally visible, so that's clumsy. */ +/* Arguments is in bytes. */ +# if defined(__STDC__) || defined(__cplusplus) + int GC_expand_hp(size_t bytes) +# else + int GC_expand_hp(bytes) + size_t bytes; +# endif +{ + int result; + DCL_LOCK_STATE; + + DISABLE_SIGNALS(); + LOCK(); + if (!GC_is_initialized) GC_init_inner(); + result = (int)GC_expand_hp_inner(divHBLKSZ((word)bytes)); + UNLOCK(); + ENABLE_SIGNALS(); + return(result); +} + +unsigned GC_fail_count = 0; + /* How many consecutive GC/expansion failures? */ + /* Reset by GC_allochblk. */ + +GC_bool GC_collect_or_expand(needed_blocks, ignore_off_page) +word needed_blocks; +GC_bool ignore_off_page; +{ + + if (!GC_incremental && !GC_dont_gc && GC_should_collect()) { + GC_notify_full_gc(); + GC_gcollect_inner(); + } else { + word blocks_to_get = GC_heapsize/(HBLKSIZE*GC_free_space_divisor) + + needed_blocks; + + if (blocks_to_get > MAXHINCR) { + word slop; + + if (ignore_off_page) { + slop = 4; + } else { + slop = 2*divHBLKSZ(BL_LIMIT); + if (slop > needed_blocks) slop = needed_blocks; + } + if (needed_blocks + slop > MAXHINCR) { + blocks_to_get = needed_blocks + slop; + } else { + blocks_to_get = MAXHINCR; + } + } + if (!GC_expand_hp_inner(blocks_to_get) + && !GC_expand_hp_inner(needed_blocks)) { + if (GC_fail_count++ < GC_max_retries) { + WARN("Out of Memory! Trying to continue ...\n", 0); + GC_notify_full_gc(); + GC_gcollect_inner(); + } else { + WARN("Out of Memory! Returning NIL!\n", 0); + return(FALSE); + } + } else if (GC_fail_count) { +# ifdef PRINTSTATS + GC_printf0("Memory available again ...\n"); +# endif + } + } + return(TRUE); +} + +/* + * Make sure the object free list for sz is not empty. + * Return a pointer to the first object on the free list. + * The object MUST BE REMOVED FROM THE FREE LIST BY THE CALLER. + * Assumes we hold the allocator lock and signals are disabled. + * + */ +ptr_t GC_allocobj(sz, kind) +word sz; +int kind; +{ + register ptr_t * flh = &(GC_obj_kinds[kind].ok_freelist[sz]); + + if (sz == 0) return(0); + + while (*flh == 0) { + ENTER_GC(); + /* Do our share of marking work */ + if(GC_incremental && !GC_dont_gc) GC_collect_a_little_inner(1); + /* Sweep blocks for objects of this size */ + GC_continue_reclaim(sz, kind); + EXIT_GC(); + if (*flh == 0) { + GC_new_hblk(sz, kind); + } + if (*flh == 0) { + ENTER_GC(); + if (!GC_collect_or_expand((word)1,FALSE)) { + EXIT_GC(); + return(0); + } + EXIT_GC(); + } + } + + return(*flh); +} |