diff options
Diffstat (limited to 'black_list.c')
| -rw-r--r-- | black_list.c | 87 |
1 files changed, 37 insertions, 50 deletions
diff --git a/black_list.c b/black_list.c index ba54f892..8dee33d8 100644 --- a/black_list.c +++ b/black_list.c @@ -14,6 +14,7 @@ * We maintain several hash tables of hblks that have had false hits. * Each contains one bit per hash bucket; If any page in the bucket * has had a false hit, we assume that all of them have. + * See the definition of page_hash_table in gc_private.h. * False hits from the stack(s) are much more dangerous than false hits * from elsewhere, since the former can pin a large object that spans the * block, eventhough it does not start on the dangerous block. @@ -30,55 +31,42 @@ * All require that the allocator lock is held. */ -# define LOG_HT_ENTRIES 14 /* Collisions are likely if heap grows */ - /* to more than 16K hblks = 64MB. */ - /* Each hash table occupies 2K bytes. */ -# define HT_ENTRIES ((word)1 << LOG_HT_ENTRIES) -# define HT_SIZE (HT_ENTRIES >> LOGWL) -typedef word black_list_t[HT_SIZE]; - -# define HASH(addr) (((addr) >> LOG_HBLKSIZE) & (HT_ENTRIES - 1)) - /* Pointers to individual tables. We replace one table by another by */ -/* switching these pointers. GC_black_lists is not used directly. */ -word * GC_new_normal_bl; - /* Nonstack false references seen at last complete */ - /* collection. */ +/* switching these pointers. */ word * GC_old_normal_bl; - /* Nonstack false references seen at preceding */ + /* Nonstack false references seen at last full */ /* collection. */ word * GC_incomplete_normal_bl; - /* Nonstack false references seen at current, */ - /* not yet completed collection. */ -word * GC_new_stack_bl; + /* Nonstack false references seen since last */ + /* full collection. */ word * GC_old_stack_bl; word * GC_incomplete_stack_bl; -# define get_bl_entry_from_index(bl, index) \ - (((bl)[divWORDSZ(index)] >> modWORDSZ(index)) & 1) -# define set_bl_entry_from_index(bl, index) \ - (bl)[divWORDSZ(index)] |= 1 << modWORDSZ(index) -# define clear_bl_entry_from_index(bl, index) \ - (bl)[divWORDSZ(index)] &= ~(1 << modWORDSZ(index)) - GC_bl_init() { # ifndef ALL_INTERIOR_POINTERS - GC_new_normal_bl = (word *)GC_scratch_alloc((word)(sizeof(black_list_t))); - GC_old_normal_bl = (word *)GC_scratch_alloc((word)(sizeof (black_list_t))); + GC_old_normal_bl = (word *) + GC_scratch_alloc((word)(sizeof (page_hash_table))); GC_incomplete_normal_bl = (word *)GC_scratch_alloc - ((word)(sizeof(black_list_t))); + ((word)(sizeof(page_hash_table))); + if (GC_old_normal_bl == 0 || GC_incomplete_normal_bl == 0) { + GC_err_printf0("Insufficient memory for black list\n"); + EXIT(); + } # endif - GC_new_stack_bl = (word *)GC_scratch_alloc((word)(sizeof(black_list_t))); - GC_old_stack_bl = (word *)GC_scratch_alloc((word)(sizeof(black_list_t))); + GC_old_stack_bl = (word *)GC_scratch_alloc((word)(sizeof(page_hash_table))); GC_incomplete_stack_bl = (word *)GC_scratch_alloc - ((word)(sizeof(black_list_t))); + ((word)(sizeof(page_hash_table))); + if (GC_old_stack_bl == 0 || GC_incomplete_stack_bl == 0) { + GC_err_printf0("Insufficient memory for black list\n"); + EXIT(); + } } void GC_clear_bl(doomed) word *doomed; { - bzero((char *)doomed, (int)HT_SIZE*sizeof(word)); + bzero((char *)doomed, (int)sizeof(page_hash_table)); } /* Signal the completion of a collection. Turn the incomplete black */ @@ -88,10 +76,8 @@ void GC_promote_black_lists() word * very_old_normal_bl = GC_old_normal_bl; word * very_old_stack_bl = GC_old_stack_bl; - GC_old_normal_bl = GC_new_normal_bl; - GC_new_normal_bl = GC_incomplete_normal_bl; - GC_old_stack_bl = GC_new_stack_bl; - GC_new_stack_bl = GC_incomplete_stack_bl; + GC_old_normal_bl = GC_incomplete_normal_bl; + GC_old_stack_bl = GC_incomplete_stack_bl; # ifndef ALL_INTERIOR_POINTERS GC_clear_bl(very_old_normal_bl); # endif @@ -109,16 +95,16 @@ word p; { if (!(GC_modws_valid_offsets[p & (sizeof(word)-1)])) return; { - register int index = HASH(p); + register int index = PHT_HASH(p); - if (HDR(p) == 0 || get_bl_entry_from_index(GC_new_normal_bl, index)) { + if (HDR(p) == 0 || get_pht_entry_from_index(GC_old_normal_bl, index)) { # ifdef PRINTBLACKLIST - if (!get_bl_entry_from_index(GC_incomplete_normal_bl, index)) { + if (!get_pht_entry_from_index(GC_incomplete_normal_bl, index)) { GC_printf1("Black listing (normal) 0x%lx\n", (unsigned long) p); } # endif - set_bl_entry_from_index(GC_incomplete_normal_bl, index); + set_pht_entry_from_index(GC_incomplete_normal_bl, index); } /* else this is probably just an interior pointer to an allocated */ /* object, and isn't worth black listing. */ } @@ -129,16 +115,16 @@ word p; void GC_add_to_black_list_stack(p) word p; { - register int index = HASH(p); + register int index = PHT_HASH(p); - if (HDR(p) == 0 || get_bl_entry_from_index(GC_new_stack_bl, index)) { + if (HDR(p) == 0 || get_pht_entry_from_index(GC_old_stack_bl, index)) { # ifdef PRINTBLACKLIST - if (!get_bl_entry_from_index(GC_incomplete_stack_bl, index)) { + if (!get_pht_entry_from_index(GC_incomplete_stack_bl, index)) { GC_printf1("Black listing (stack) 0x%lx\n", (unsigned long)p); } # endif - set_bl_entry_from_index(GC_incomplete_stack_bl, index); + set_pht_entry_from_index(GC_incomplete_stack_bl, index); } } @@ -154,30 +140,31 @@ struct hblk * GC_is_black_listed(h, len) struct hblk * h; word len; { - register int index = HASH((word)h); + register int index = PHT_HASH((word)h); register word i; word nblocks = divHBLKSZ(len); # ifndef ALL_INTERIOR_POINTERS - if (get_bl_entry_from_index(GC_new_normal_bl, index) - && get_bl_entry_from_index(GC_old_normal_bl, index)) { + if (get_pht_entry_from_index(GC_old_normal_bl, index) + || get_pht_entry_from_index(GC_incomplete_normal_bl, index)) { return(h+1); } # endif for (i = 0; ; ) { - if (GC_new_stack_bl[divWORDSZ(index)] == 0) { + if (GC_old_stack_bl[divWORDSZ(index)] == 0 + && GC_incomplete_stack_bl[divWORDSZ(index)] == 0) { /* An easy case */ i += WORDSZ - modWORDSZ(index); } else { - if (get_bl_entry_from_index(GC_new_stack_bl, index) - && get_bl_entry_from_index(GC_old_stack_bl, index)) { + if (get_pht_entry_from_index(GC_old_stack_bl, index) + || get_pht_entry_from_index(GC_incomplete_stack_bl, index)) { return(h+i+1); } i++; } if (i >= nblocks) break; - index = HASH((word)(h+i)); + index = PHT_HASH((word)(h+i)); } return(0); } |