diff options
Diffstat (limited to 'allochblk.c')
| -rw-r--r-- | allochblk.c | 155 |
1 files changed, 51 insertions, 104 deletions
diff --git a/allochblk.c b/allochblk.c index 1dcf581b..48212b7f 100644 --- a/allochblk.c +++ b/allochblk.c @@ -38,61 +38,24 @@ struct hblk *GC_savhbp = (struct hblk *)0; /* heap block preceding next */ /* block to be examined by */ /* GC_allochblk. */ -/* - * Return TRUE if there is a heap block sufficient for object size sz, - * FALSE otherwise. Advance GC_savhbp to point to the block prior to the - * first such block. - */ -bool GC_sufficient_hb(sz, kind) -word sz; +/* Initialize hdr for a block containing the indicated size and */ +/* kind of objects. */ +static setup_header(hhdr, sz, kind) +register hdr * hhdr; +word sz; /* object size in words */ int kind; { -register struct hblk *hbp; -register hdr * hhdr; -struct hblk *prevhbp; -signed_word size_needed; -signed_word size_avail; -bool first_time = TRUE; - - size_needed = WORDS_TO_BYTES(sz); - size_needed = (size_needed+HDR_BYTES+HBLKSIZE-1) & ~HBLKMASK; -# ifdef DEBUG - GC_printf("GC_sufficient_hb: sz = %ld, size_needed = 0x%lx\n", - (long)sz, (unsigned long)size_needed); -# endif - /* search for a big enough block in free list */ - hbp = GC_savhbp; - hhdr = HDR(hbp); - for(;;) { - prevhbp = hbp; - hbp = ((prevhbp == (struct hblk *)0) - ? GC_hblkfreelist - : hhdr->hb_next); - hhdr = HDR(hbp); - - if( prevhbp == GC_savhbp && !first_time) { - /* no sufficiently big blocks on free list */ - return(FALSE); - } - first_time = 0; - if( hbp == (struct hblk *)0 ) continue; - size_avail = hhdr->hb_sz; - if ( kind != PTRFREE || size_needed > MAX_BLACK_LIST_ALLOC) { - struct hblk * thishbp; - struct hblk * lasthbp = hbp; - - while ((ptr_t)lasthbp - (ptr_t)hbp < size_avail - && (thishbp = GC_is_black_listed(lasthbp, - (word)size_needed))) { - lasthbp = thishbp; - } - size_avail -= (ptr_t)lasthbp - (ptr_t)hbp; - } - if( size_avail >= size_needed ) { - GC_savhbp = prevhbp; - return(TRUE); - } - } + /* Set size, kind and mark proc fields */ + hhdr -> hb_sz = sz; + hhdr -> hb_obj_kind = kind; + hhdr -> hb_mark_proc = GC_obj_kinds[kind].ok_mark_proc; + + /* Add description of valid object pointers */ + GC_add_map_entry(sz); + hhdr -> hb_map = GC_obj_map[sz > MAXOBJSZ? 0 : sz]; + + /* Clear mark bits */ + GC_clear_hdr_marks(hhdr); } /* @@ -134,31 +97,10 @@ int kind; hhdr = HDR(hbp); if( prevhbp == GC_savhbp && !first_time) { - /* no sufficiently big blocks on free list, */ - /* let thishbp --> a newly-allocated block, */ - /* free it (to merge into existing block */ - /* list) and start the search again, this */ - /* time with guaranteed success. */ - word size_to_get = size_needed + GC_hincr * HBLKSIZE; - - if (! GC_expand_hp_inner(divHBLKSZ(size_to_get))) { - if (! GC_expand_hp_inner(divHBLKSZ((word)size_needed))) - { - /* GC_printf("Out of Memory! Giving up ...\n"); */ - /* There are other things we could try. It */ - /* would probably be reasonable to clear */ - /* black lists at tthis point. */ - return(0); - } else { - WARN("Out of Memory! Trying to continue ...\n"); - GC_gcollect_inner(TRUE); - } - } - update_GC_hincr; - return (GC_allochblk(sz, kind)); + return(0); } - first_time = 0; + first_time = FALSE; if( hbp == 0 ) continue; @@ -205,7 +147,30 @@ int kind; phdr = hhdr; hbp = thishbp; hhdr = thishdr; - } + } else if (size_avail == 0 + && size_needed == HBLKSIZE + && prevhbp != 0) { + static unsigned count = 0; + + /* The block is completely blacklisted. We need */ + /* to drop some such blocks, since otherwise we spend */ + /* all our time traversing them if pointerfree */ + /* blocks are unpopular. */ + /* A dropped block will be reconsidered at next GC. */ + if ((++count & 3) == 0) { + /* Allocate and drop the block */ + phdr -> hb_next = hhdr -> hb_next; + GC_install_counts(hbp, hhdr->hb_sz); + setup_header(hhdr, + BYTES_TO_WORDS(hhdr->hb_sz - HDR_BYTES), + PTRFREE); + if (GC_savhbp == hbp) GC_savhbp = prevhbp; + /* Restore hbp to point at free block */ + hbp = prevhbp; + hhdr = phdr; + if (hbp == GC_savhbp) first_time = TRUE; + } + } } if( size_avail >= size_needed ) { /* found a big enough block */ @@ -237,34 +202,16 @@ int kind; } } - /* set size and mask field of *thishbp correctly */ - thishdr->hb_sz = sz; - /* Clear block if necessary */ if (sz > MAXOBJSZ && GC_obj_kinds[kind].ok_init) { bzero((char *)thishbp + HDR_BYTES, (int)(size_needed - HDR_BYTES)); } - - /* Clear mark bits */ - { - register word *p = (word *)(&(thishdr -> hb_marks[0])); - register word * plim = - (word *)(&(thishdr -> hb_marks[MARK_BITS_SZ])); - while (p < plim) { - *p++ = 0; - } - } - - /* Add it to data structure describing hblks in use */ - GC_install_counts(thishbp, (word)size_needed); - - /* Add description of valid object pointers. */ - GC_add_map_entry(sz); - thishdr -> hb_map = GC_obj_map[sz > MAXOBJSZ? 0 : sz]; + + /* Set up header */ + setup_header(thishdr, sz, kind); - /* Set kind related fields */ - thishdr -> hb_obj_kind = kind; - thishdr -> hb_mark_proc = GC_obj_kinds[kind].ok_mark_proc; + /* Add it to map of valid blocks */ + GC_install_counts(thishbp, (word)size_needed); return( thishbp ); } @@ -311,10 +258,10 @@ register signed_word size; /* Check for duplicate deallocation in the easy case */ if (hbp != 0 && (ptr_t)p + size > (ptr_t)hbp || prevhbp != 0 && (ptr_t)prevhbp + prevhdr->hb_sz > (ptr_t)p) { - GC_printf("Duplicate large block deallocation of 0x%lx\n", - (unsigned long) p); - GC_printf("Surrounding free blocks are 0x%lx and 0x%lx\n", - (unsigned long) prevhbp, (unsigned long) hbp); + GC_printf1("Duplicate large block deallocation of 0x%lx\n", + (unsigned long) p); + GC_printf2("Surrounding free blocks are 0x%lx and 0x%lx\n", + (unsigned long) prevhbp, (unsigned long) hbp); } /* Coalesce with successor, if possible */ |