Initial revision

1 files changed, 739 insertions, 0 deletions

diff --git a/gc/reclaim.c b/gc/reclaim.c
new file mode 100644
index 0000000..3085946
--- /dev/null
+++ b/gc/reclaim.c
@@ -0,0 +1,739 @@
+/* 
+ * 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 15, 1996 2:41 pm PST */
+
+#include <stdio.h>
+#include "gc_priv.h"
+
+signed_word GC_mem_found = 0;
+			/* Number of words of memory reclaimed     */
+
+static void report_leak(p, sz)
+ptr_t p;
+word sz;
+{
+    if (HDR(p) -> hb_obj_kind == PTRFREE) {
+        GC_err_printf0("Leaked atomic object at ");
+    } else {
+        GC_err_printf0("Leaked composite object at ");
+    }
+    if (GC_debugging_started && GC_has_debug_info(p)) {
+        GC_print_obj(p);
+    } else {
+        GC_err_printf2("0x%lx (appr. size = %ld)\n",
+       		      (unsigned long)p,
+       		      (unsigned long)WORDS_TO_BYTES(sz));
+    }
+}
+
+#   define FOUND_FREE(hblk, word_no) \
+      { \
+         report_leak((ptr_t)hblk + WORDS_TO_BYTES(word_no), \
+         	     HDR(hblk) -> hb_sz); \
+      }
+
+/*
+ * reclaim phase
+ *
+ */
+
+
+/*
+ * Test whether a block is completely empty, i.e. contains no marked
+ * objects.  This does not require the block to be in physical
+ * memory.
+ */
+ 
+GC_bool GC_block_empty(hhdr)
+register hdr * hhdr;
+{
+    register word *p = (word *)(&(hhdr -> hb_marks[0]));
+    register word * plim =
+	    		(word *)(&(hhdr -> hb_marks[MARK_BITS_SZ]));
+    while (p < plim) {
+	if (*p++) return(FALSE);
+    }
+    return(TRUE);
+}
+
+# ifdef GATHERSTATS
+#   define INCR_WORDS(sz) n_words_found += (sz)
+# else
+#   define INCR_WORDS(sz)
+# endif
+/*
+ * Restore unmarked small objects in h of size sz to the object
+ * free list.  Returns the new list.
+ * Clears unmarked objects.
+ */
+/*ARGSUSED*/
+ptr_t GC_reclaim_clear(hbp, hhdr, sz, list)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+register hdr * hhdr;
+register ptr_t list;
+register word sz;
+{
+    register int word_no;
+    register word *p, *q, *plim;
+#   ifdef GATHERSTATS
+        register int n_words_found = 0;
+#   endif        
+    
+    p = (word *)(hbp->hb_body);
+    word_no = HDR_WORDS;
+    plim = (word *)((((word)hbp) + HBLKSIZE)
+		   - WORDS_TO_BYTES(sz));
+
+    /* go through all words in block */
+	while( p <= plim )  {
+	    if( mark_bit_from_hdr(hhdr, word_no) ) {
+		p += sz;
+	    } else {
+		INCR_WORDS(sz);
+		/* object is available - put on list */
+		    obj_link(p) = list;
+		    list = ((ptr_t)p);
+		/* Clear object, advance p to next object in the process */
+		    q = p + sz;
+                    p++; /* Skip link field */
+                    while (p < q) {
+			*p++ = 0;
+		    }
+	    }
+	    word_no += sz;
+	}
+#   ifdef GATHERSTATS
+	GC_mem_found += n_words_found;
+#   endif
+    return(list);
+}
+
+#ifndef SMALL_CONFIG
+
+/*
+ * A special case for 2 word composite objects (e.g. cons cells):
+ */
+/*ARGSUSED*/
+ptr_t GC_reclaim_clear2(hbp, hhdr, list)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+hdr * hhdr;
+register ptr_t list;
+{
+    register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+    register word *p, *plim;
+#   ifdef GATHERSTATS
+        register int n_words_found = 0;
+#   endif
+    register word mark_word;
+    register int i;
+#   define DO_OBJ(start_displ) \
+	if (!(mark_word & ((word)1 << start_displ))) { \
+	    p[start_displ] = (word)list; \
+	    list = (ptr_t)(p+start_displ); \
+	    p[start_displ+1] = 0; \
+	    INCR_WORDS(2); \
+	}
+    
+    p = (word *)(hbp->hb_body);
+    plim = (word *)(((word)hbp) + HBLKSIZE);
+
+    /* go through all words in block */
+	while( p < plim )  {
+	    mark_word = *mark_word_addr++;
+	    for (i = 0; i < WORDSZ; i += 8) {
+		DO_OBJ(0);
+		DO_OBJ(2);
+		DO_OBJ(4);
+		DO_OBJ(6);
+		p += 8;
+		mark_word >>= 8;
+	    }
+	}	        
+#   ifdef GATHERSTATS
+	GC_mem_found += n_words_found;
+#   endif
+    return(list);
+#   undef DO_OBJ
+}
+
+/*
+ * Another special case for 4 word composite objects:
+ */
+/*ARGSUSED*/
+ptr_t GC_reclaim_clear4(hbp, hhdr, list)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+hdr * hhdr;
+register ptr_t list;
+{
+    register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+    register word *p, *plim;
+#   ifdef GATHERSTATS
+        register int n_words_found = 0;
+#   endif
+    register word mark_word;
+#   define DO_OBJ(start_displ) \
+	if (!(mark_word & ((word)1 << start_displ))) { \
+	    p[start_displ] = (word)list; \
+	    list = (ptr_t)(p+start_displ); \
+	    p[start_displ+1] = 0; \
+	    p[start_displ+2] = 0; \
+	    p[start_displ+3] = 0; \
+	    INCR_WORDS(4); \
+	}
+    
+    p = (word *)(hbp->hb_body);
+    plim = (word *)(((word)hbp) + HBLKSIZE);
+
+    /* go through all words in block */
+	while( p < plim )  {
+	    mark_word = *mark_word_addr++;
+	    DO_OBJ(0);
+	    DO_OBJ(4);
+	    DO_OBJ(8);
+	    DO_OBJ(12);
+	    DO_OBJ(16);
+	    DO_OBJ(20);
+	    DO_OBJ(24);
+	    DO_OBJ(28);
+#	    if CPP_WORDSZ == 64
+	      DO_OBJ(32);
+	      DO_OBJ(36);
+	      DO_OBJ(40);
+	      DO_OBJ(44);
+	      DO_OBJ(48);
+	      DO_OBJ(52);
+	      DO_OBJ(56);
+	      DO_OBJ(60);
+#	    endif
+	    p += WORDSZ;
+	}	        
+#   ifdef GATHERSTATS
+	GC_mem_found += n_words_found;
+#   endif
+    return(list);
+#   undef DO_OBJ
+}
+
+#endif /* !SMALL_CONFIG */
+
+/* The same thing, but don't clear objects: */
+/*ARGSUSED*/
+ptr_t GC_reclaim_uninit(hbp, hhdr, sz, list)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+register hdr * hhdr;
+register ptr_t list;
+register word sz;
+{
+    register int word_no;
+    register word *p, *plim;
+#   ifdef GATHERSTATS
+        register int n_words_found = 0;
+#   endif
+    
+    p = (word *)(hbp->hb_body);
+    word_no = HDR_WORDS;
+    plim = (word *)((((word)hbp) + HBLKSIZE)
+		   - WORDS_TO_BYTES(sz));
+
+    /* go through all words in block */
+	while( p <= plim )  {
+	    if( !mark_bit_from_hdr(hhdr, word_no) ) {
+		INCR_WORDS(sz);
+		/* object is available - put on list */
+		    obj_link(p) = list;
+		    list = ((ptr_t)p);
+	    }
+	    p += sz;
+	    word_no += sz;
+	}
+#   ifdef GATHERSTATS
+	GC_mem_found += n_words_found;
+#   endif
+    return(list);
+}
+
+/* Don't really reclaim objects, just check for unmarked ones: */
+/*ARGSUSED*/
+void GC_reclaim_check(hbp, hhdr, sz)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+register hdr * hhdr;
+register word sz;
+{
+    register int word_no;
+    register word *p, *plim;
+#   ifdef GATHERSTATS
+        register int n_words_found = 0;
+#   endif
+    
+    p = (word *)(hbp->hb_body);
+    word_no = HDR_WORDS;
+    plim = (word *)((((word)hbp) + HBLKSIZE)
+		   - WORDS_TO_BYTES(sz));
+
+    /* go through all words in block */
+	while( p <= plim )  {
+	    if( !mark_bit_from_hdr(hhdr, word_no) ) {
+		FOUND_FREE(hbp, word_no);
+	    }
+	    p += sz;
+	    word_no += sz;
+	}
+}
+
+#ifndef SMALL_CONFIG
+/*
+ * Another special case for 2 word atomic objects:
+ */
+/*ARGSUSED*/
+ptr_t GC_reclaim_uninit2(hbp, hhdr, list)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+hdr * hhdr;
+register ptr_t list;
+{
+    register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+    register word *p, *plim;
+#   ifdef GATHERSTATS
+        register int n_words_found = 0;
+#   endif
+    register word mark_word;
+    register int i;
+#   define DO_OBJ(start_displ) \
+	if (!(mark_word & ((word)1 << start_displ))) { \
+	    p[start_displ] = (word)list; \
+	    list = (ptr_t)(p+start_displ); \
+	    INCR_WORDS(2); \
+	}
+    
+    p = (word *)(hbp->hb_body);
+    plim = (word *)(((word)hbp) + HBLKSIZE);
+
+    /* go through all words in block */
+	while( p < plim )  {
+	    mark_word = *mark_word_addr++;
+	    for (i = 0; i < WORDSZ; i += 8) {
+		DO_OBJ(0);
+		DO_OBJ(2);
+		DO_OBJ(4);
+		DO_OBJ(6);
+		p += 8;
+		mark_word >>= 8;
+	    }
+	}	        
+#   ifdef GATHERSTATS
+	GC_mem_found += n_words_found;
+#   endif
+    return(list);
+#   undef DO_OBJ
+}
+
+/*
+ * Another special case for 4 word atomic objects:
+ */
+/*ARGSUSED*/
+ptr_t GC_reclaim_uninit4(hbp, hhdr, list)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+hdr * hhdr;
+register ptr_t list;
+{
+    register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+    register word *p, *plim;
+#   ifdef GATHERSTATS
+        register int n_words_found = 0;
+#   endif
+    register word mark_word;
+#   define DO_OBJ(start_displ) \
+	if (!(mark_word & ((word)1 << start_displ))) { \
+	    p[start_displ] = (word)list; \
+	    list = (ptr_t)(p+start_displ); \
+	    INCR_WORDS(4); \
+	}
+    
+    p = (word *)(hbp->hb_body);
+    plim = (word *)(((word)hbp) + HBLKSIZE);
+
+    /* go through all words in block */
+	while( p < plim )  {
+	    mark_word = *mark_word_addr++;
+	    DO_OBJ(0);
+	    DO_OBJ(4);
+	    DO_OBJ(8);
+	    DO_OBJ(12);
+	    DO_OBJ(16);
+	    DO_OBJ(20);
+	    DO_OBJ(24);
+	    DO_OBJ(28);
+#	    if CPP_WORDSZ == 64
+	      DO_OBJ(32);
+	      DO_OBJ(36);
+	      DO_OBJ(40);
+	      DO_OBJ(44);
+	      DO_OBJ(48);
+	      DO_OBJ(52);
+	      DO_OBJ(56);
+	      DO_OBJ(60);
+#	    endif
+	    p += WORDSZ;
+	}	        
+#   ifdef GATHERSTATS
+	GC_mem_found += n_words_found;
+#   endif
+    return(list);
+#   undef DO_OBJ
+}
+
+/* Finally the one word case, which never requires any clearing: */
+/*ARGSUSED*/
+ptr_t GC_reclaim1(hbp, hhdr, list)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+hdr * hhdr;
+register ptr_t list;
+{
+    register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+    register word *p, *plim;
+#   ifdef GATHERSTATS
+        register int n_words_found = 0;
+#   endif
+    register word mark_word;
+    register int i;
+#   define DO_OBJ(start_displ) \
+	if (!(mark_word & ((word)1 << start_displ))) { \
+	    p[start_displ] = (word)list; \
+	    list = (ptr_t)(p+start_displ); \
+	    INCR_WORDS(1); \
+	}
+    
+    p = (word *)(hbp->hb_body);
+    plim = (word *)(((word)hbp) + HBLKSIZE);
+
+    /* go through all words in block */
+	while( p < plim )  {
+	    mark_word = *mark_word_addr++;
+	    for (i = 0; i < WORDSZ; i += 4) {
+		DO_OBJ(0);
+		DO_OBJ(1);
+		DO_OBJ(2);
+		DO_OBJ(3);
+		p += 4;
+		mark_word >>= 4;
+	    }
+	}	        
+#   ifdef GATHERSTATS
+	GC_mem_found += n_words_found;
+#   endif
+    return(list);
+#   undef DO_OBJ
+}
+
+#endif /* !SMALL_CONFIG */
+
+/*
+ * Restore unmarked small objects in the block pointed to by hbp
+ * to the appropriate object free list.
+ * If entirely empty blocks are to be completely deallocated, then
+ * caller should perform that check.
+ */
+void GC_reclaim_small_nonempty_block(hbp, report_if_found)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+int report_if_found;		/* Abort if a reclaimable object is found */
+{
+    hdr * hhdr;
+    register word sz;		/* size of objects in current block	*/
+    register struct obj_kind * ok;
+    register ptr_t * flh;
+    register int kind;
+    
+    hhdr = HDR(hbp);
+    sz = hhdr -> hb_sz;
+    hhdr -> hb_last_reclaimed = (unsigned short) GC_gc_no;
+    kind = hhdr -> hb_obj_kind;
+    ok = &GC_obj_kinds[kind];
+    flh = &(ok -> ok_freelist[sz]);
+    GC_write_hint(hbp);
+
+    if (report_if_found) {
+	GC_reclaim_check(hbp, hhdr, sz);
+    } else if (ok -> ok_init) {
+      switch(sz) {
+#      ifndef SMALL_CONFIG
+        case 1:
+            *flh = GC_reclaim1(hbp, hhdr, *flh);
+            break;
+        case 2:
+            *flh = GC_reclaim_clear2(hbp, hhdr, *flh);
+            break;
+        case 4:
+            *flh = GC_reclaim_clear4(hbp, hhdr, *flh);
+            break;
+#      endif
+        default:
+            *flh = GC_reclaim_clear(hbp, hhdr, sz, *flh);
+            break;
+      }
+    } else {
+      switch(sz) {
+#      ifndef SMALL_CONFIG
+        case 1:
+            *flh = GC_reclaim1(hbp, hhdr, *flh);
+            break;
+        case 2:
+            *flh = GC_reclaim_uninit2(hbp, hhdr, *flh);
+            break;
+        case 4:
+            *flh = GC_reclaim_uninit4(hbp, hhdr, *flh);
+            break;
+#      endif
+        default:
+            *flh = GC_reclaim_uninit(hbp, hhdr, sz, *flh);
+            break;
+      }
+    } 
+    if (IS_UNCOLLECTABLE(kind)) GC_set_hdr_marks(hhdr);
+}
+
+/*
+ * Restore an unmarked large object or an entirely empty blocks of small objects
+ * to the heap block free list.
+ * Otherwise enqueue the block for later processing
+ * by GC_reclaim_small_nonempty_block.
+ * If report_if_found is TRUE, then process any block immediately, and
+ * simply report free objects; do not actually reclaim them.
+ */
+void GC_reclaim_block(hbp, report_if_found)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+word report_if_found;		/* Abort if a reclaimable object is found */
+{
+    register hdr * hhdr;
+    register word sz;		/* size of objects in current block	*/
+    register struct obj_kind * ok;
+    struct hblk ** rlh;
+
+    hhdr = HDR(hbp);
+    sz = hhdr -> hb_sz;
+    ok = &GC_obj_kinds[hhdr -> hb_obj_kind];
+
+    if( sz > MAXOBJSZ ) {  /* 1 big object */
+        if( !mark_bit_from_hdr(hhdr, HDR_WORDS) ) {
+	    if (report_if_found) {
+	      FOUND_FREE(hbp, HDR_WORDS);
+	    } else {
+#	      ifdef GATHERSTATS
+	        GC_mem_found += sz;
+#	      endif
+	      GC_freehblk(hbp);
+	    }
+	}
+    } else {
+        GC_bool empty = GC_block_empty(hhdr);
+        if (report_if_found) {
+    	  GC_reclaim_small_nonempty_block(hbp, (int)report_if_found);
+        } else if (empty) {
+#	  ifdef GATHERSTATS
+            GC_mem_found += BYTES_TO_WORDS(HBLKSIZE);
+#	  endif
+          GC_freehblk(hbp);
+        } else {
+          /* group of smaller objects, enqueue the real work */
+          rlh = &(ok -> ok_reclaim_list[sz]);
+          hhdr -> hb_next = *rlh;
+          *rlh = hbp;
+        }
+    }
+}
+
+#if !defined(NO_DEBUGGING)
+/* Routines to gather and print heap block info 	*/
+/* intended for debugging.  Otherwise should be called	*/
+/* with lock.						*/
+static size_t number_of_blocks;
+static size_t total_bytes;
+
+/* Number of set bits in a word.  Not performance critical.	*/
+static int set_bits(n)
+word n;
+{
+    register word m = n;
+    register int result = 0;
+    
+    while (m > 0) {
+    	if (m & 1) result++;
+    	m >>= 1;
+    }
+    return(result);
+}
+
+/* Return the number of set mark bits in the given header	*/
+int GC_n_set_marks(hhdr)
+hdr * hhdr;
+{
+    register int result = 0;
+    register int i;
+    
+    for (i = 0; i < MARK_BITS_SZ; i++) {
+        result += set_bits(hhdr -> hb_marks[i]);
+    }
+    return(result);
+}
+
+/*ARGSUSED*/
+void GC_print_block_descr(h, dummy)
+struct hblk *h;
+word dummy;
+{
+    register hdr * hhdr = HDR(h);
+    register size_t bytes = WORDS_TO_BYTES(hhdr -> hb_sz);
+    
+    GC_printf3("(%lu:%lu,%lu)", (unsigned long)(hhdr -> hb_obj_kind),
+    			        (unsigned long)bytes,
+    			        (unsigned long)(GC_n_set_marks(hhdr)));
+    bytes += HDR_BYTES + HBLKSIZE-1;
+    bytes &= ~(HBLKSIZE-1);
+    total_bytes += bytes;
+    number_of_blocks++;
+}
+
+void GC_print_block_list()
+{
+    GC_printf0("(kind(0=ptrfree,1=normal,2=unc.,3=stubborn):size_in_bytes, #_marks_set)\n");
+    number_of_blocks = 0;
+    total_bytes = 0;
+    GC_apply_to_all_blocks(GC_print_block_descr, (word)0);
+    GC_printf2("\nblocks = %lu, bytes = %lu\n",
+    	       (unsigned long)number_of_blocks,
+    	       (unsigned long)total_bytes);
+}
+
+#endif /* NO_DEBUGGING */
+
+/*
+ * Perform GC_reclaim_block on the entire heap, after first clearing
+ * small object free lists (if we are not just looking for leaks).
+ */
+void GC_start_reclaim(report_if_found)
+int report_if_found;		/* Abort if a GC_reclaimable object is found */
+{
+    int kind;
+    
+    /* Clear reclaim- and free-lists */
+      for (kind = 0; kind < GC_n_kinds; kind++) {
+        register ptr_t *fop;
+        register ptr_t *lim;
+        register struct hblk ** rlp;
+        register struct hblk ** rlim;
+        register struct hblk ** rlist = GC_obj_kinds[kind].ok_reclaim_list;
+        
+        if (rlist == 0) continue;	/* This kind not used.	*/
+        if (!report_if_found) {
+            lim = &(GC_obj_kinds[kind].ok_freelist[MAXOBJSZ+1]);
+	    for( fop = GC_obj_kinds[kind].ok_freelist; fop < lim; fop++ ) {
+	      *fop = 0;
+	    }
+	} /* otherwise free list objects are marked, 	*/
+	  /* and its safe to leave them			*/
+	rlim = rlist + MAXOBJSZ+1;
+	for( rlp = rlist; rlp < rlim; rlp++ ) {
+	    *rlp = 0;
+	}
+      }
+    
+#   ifdef PRINTBLOCKS
+        GC_printf0("GC_reclaim: current block sizes:\n");
+        GC_print_block_list();
+#   endif
+
+  /* Go through all heap blocks (in hblklist) and reclaim unmarked objects */
+  /* or enqueue the block for later processing.				   */
+    GC_apply_to_all_blocks(GC_reclaim_block, (word)report_if_found);
+    
+}
+
+/*
+ * Sweep blocks of the indicated object size and kind until either the
+ * appropriate free list is nonempty, or there are no more blocks to
+ * sweep.
+ */
+void GC_continue_reclaim(sz, kind)
+word sz;	/* words */
+int kind;
+{
+    register hdr * hhdr;
+    register struct hblk * hbp;
+    register struct obj_kind * ok = &(GC_obj_kinds[kind]);
+    struct hblk ** rlh = ok -> ok_reclaim_list;
+    ptr_t *flh = &(ok -> ok_freelist[sz]);
+    
+    if (rlh == 0) return;	/* No blocks of this kind.	*/
+    rlh += sz;
+    while ((hbp = *rlh) != 0) {
+        hhdr = HDR(hbp);
+        *rlh = hhdr -> hb_next;
+        GC_reclaim_small_nonempty_block(hbp, FALSE);
+        if (*flh != 0) break;
+    }
+}
+
+/*
+ * Reclaim all small blocks waiting to be reclaimed.
+ * Abort and return FALSE when/if (*stop_func)() returns TRUE.
+ * If this returns TRUE, then it's safe to restart the world
+ * with incorrectly cleared mark bits.
+ * If ignore_old is TRUE, then reclain only blocks that have been 
+ * recently reclaimed, and discard the rest.
+ * Stop_func may be 0.
+ */
+GC_bool GC_reclaim_all(stop_func, ignore_old)
+GC_stop_func stop_func;
+GC_bool ignore_old;
+{
+    register word sz;
+    register int kind;
+    register hdr * hhdr;
+    register struct hblk * hbp;
+    register struct obj_kind * ok;
+    struct hblk ** rlp;
+    struct hblk ** rlh;
+#   ifdef PRINTTIMES
+	CLOCK_TYPE start_time;
+	CLOCK_TYPE done_time;
+	
+	GET_TIME(start_time);
+#   endif
+    
+    for (kind = 0; kind < GC_n_kinds; kind++) {
+    	ok = &(GC_obj_kinds[kind]);
+    	rlp = ok -> ok_reclaim_list;
+    	if (rlp == 0) continue;
+    	for (sz = 1; sz <= MAXOBJSZ; sz++) {
+    	    rlh = rlp + sz;
+    	    while ((hbp = *rlh) != 0) {
+    	        if (stop_func != (GC_stop_func)0 && (*stop_func)()) {
+    	            return(FALSE);
+    	        }
+        	hhdr = HDR(hbp);
+        	*rlh = hhdr -> hb_next;
+        	if (!ignore_old || hhdr -> hb_last_reclaimed == GC_gc_no - 1) {
+        	    /* It's likely we'll need it this time, too	*/
+        	    /* It's been touched recently, so this	*/
+        	    /* shouldn't trigger paging.		*/
+        	    GC_reclaim_small_nonempty_block(hbp, FALSE);
+        	}
+            }
+        }
+    }
+#   ifdef PRINTTIMES
+	GET_TIME(done_time);
+	GC_printf1("Disposing of reclaim lists took %lu msecs\n",
+	           MS_TIME_DIFF(done_time,start_time));
+#   endif
+    return(TRUE);
+}