=================================================================== RCS file: /home/cvs/OpenXM_contrib/gc/Attic/reclaim.c,v retrieving revision 1.1 retrieving revision 1.1.1.2 diff -u -p -r1.1 -r1.1.1.2 --- OpenXM_contrib/gc/Attic/reclaim.c 1999/11/27 10:58:33 1.1 +++ OpenXM_contrib/gc/Attic/reclaim.c 2000/04/14 11:07:57 1.1.1.2 @@ -1,6 +1,8 @@ /* * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers - * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved. + * Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved. + * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved. + * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved. * * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. @@ -11,7 +13,6 @@ * 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 #include "gc_priv.h" @@ -19,7 +20,6 @@ signed_word GC_mem_found = 0; /* Number of words of memory reclaimed */ -# ifdef FIND_LEAK static void report_leak(p, sz) ptr_t p; word sz; @@ -39,13 +39,10 @@ word sz; } # define FOUND_FREE(hblk, word_no) \ - if (abort_if_found) { \ + { \ report_leak((ptr_t)hblk + WORDS_TO_BYTES(word_no), \ HDR(hblk) -> hb_sz); \ } -# else -# define FOUND_FREE(hblk, word_no) -# endif /* * reclaim phase @@ -71,6 +68,139 @@ register hdr * hhdr; return(TRUE); } +/* The following functions sometimes return a DONT_KNOW value. */ +#define DONT_KNOW 2 + +#ifdef SMALL_CONFIG +# define GC_block_nearly_full1(hhdr, pat1) DONT_KNOW +# define GC_block_nearly_full3(hhdr, pat1, pat2) DONT_KNOW +# define GC_block_nearly_full(hhdr) DONT_KNOW +#else + +/* + * Test whether nearly all of the mark words consist of the same + * repeating pattern. + */ +#define FULL_THRESHOLD (MARK_BITS_SZ/16) + +GC_bool GC_block_nearly_full1(hhdr, pat1) +hdr *hhdr; +word pat1; +{ + unsigned i; + unsigned misses = 0; + GC_ASSERT((MARK_BITS_SZ & 1) == 0); + for (i = 0; i < MARK_BITS_SZ; ++i) { + if ((hhdr -> hb_marks[i] | ~pat1) != ONES) { + if (++misses > FULL_THRESHOLD) return FALSE; + } + } + return TRUE; +} + +/* + * Test whether the same repeating 3 word pattern occurs in nearly + * all the mark bit slots. + * This is used as a heuristic, so we're a bit sloppy and ignore + * the last one or two words. + */ +GC_bool GC_block_nearly_full3(hhdr, pat1, pat2, pat3) +hdr *hhdr; +word pat1, pat2, pat3; +{ + unsigned i; + unsigned misses = 0; + + if (MARK_BITS_SZ < 4) { + return DONT_KNOW; + } + for (i = 0; i < MARK_BITS_SZ - 2; i += 3) { + if ((hhdr -> hb_marks[i] | ~pat1) != ONES) { + if (++misses > FULL_THRESHOLD) return FALSE; + } + if ((hhdr -> hb_marks[i+1] | ~pat2) != ONES) { + if (++misses > FULL_THRESHOLD) return FALSE; + } + if ((hhdr -> hb_marks[i+2] | ~pat3) != ONES) { + if (++misses > FULL_THRESHOLD) return FALSE; + } + } + return TRUE; +} + +/* Check whether a small object block is nearly full by looking at only */ +/* the mark bits. */ +/* We manually precomputed the mark bit patterns that need to be */ +/* checked for, and we give up on the ones that are unlikely to occur, */ +/* or have period > 3. */ +/* This would be a lot easier with a mark bit per object instead of per */ +/* word, but that would rewuire computing object numbers in the mark */ +/* loop, which would require different data structures ... */ +GC_bool GC_block_nearly_full(hhdr) +hdr *hhdr; +{ + int sz = hhdr -> hb_sz; + +# if CPP_WORDSZ != 32 && CPP_WORDSZ != 64 + return DONT_KNOW; /* Shouldn't be used in any standard config. */ +# endif + if (0 != HDR_WORDS) return DONT_KNOW; + /* Also shouldn't happen */ +# if CPP_WORDSZ == 32 + switch(sz) { + case 1: + return GC_block_nearly_full1(hhdr, 0xffffffffl); + case 2: + return GC_block_nearly_full1(hhdr, 0x55555555l); + case 4: + return GC_block_nearly_full1(hhdr, 0x11111111l); + case 6: + return GC_block_nearly_full3(hhdr, 0x41041041l, + 0x10410410l, + 0x04104104l); + case 8: + return GC_block_nearly_full1(hhdr, 0x01010101l); + case 12: + return GC_block_nearly_full3(hhdr, 0x01001001l, + 0x10010010l, + 0x00100100l); + case 16: + return GC_block_nearly_full1(hhdr, 0x00010001l); + case 32: + return GC_block_nearly_full1(hhdr, 0x00000001l); + default: + return DONT_KNOW; + } +# endif +# if CPP_WORDSZ == 64 + switch(sz) { + case 1: + return GC_block_nearly_full1(hhdr, 0xffffffffffffffffl); + case 2: + return GC_block_nearly_full1(hhdr, 0x5555555555555555l); + case 4: + return GC_block_nearly_full1(hhdr, 0x1111111111111111l); + case 6: + return GC_block_nearly_full3(hhdr, 0x1041041041041041l, + 0x4104104104104104l, + 0x0410410410410410l); + case 8: + return GC_block_nearly_full1(hhdr, 0x0101010101010101l); + case 12: + return GC_block_nearly_full3(hhdr, 0x1001001001001001l, + 0x0100100100100100l, + 0x0010010010010010l); + case 16: + return GC_block_nearly_full1(hhdr, 0x0001000100010001l); + case 32: + return GC_block_nearly_full1(hhdr, 0x0000000100000001l); + default: + return DONT_KNOW; + } +# endif +} +#endif /* !SMALL_CONFIG */ + # ifdef GATHERSTATS # define INCR_WORDS(sz) n_words_found += (sz) # else @@ -82,10 +212,9 @@ register hdr * hhdr; * Clears unmarked objects. */ /*ARGSUSED*/ -ptr_t GC_reclaim_clear(hbp, hhdr, sz, list, abort_if_found) +ptr_t GC_reclaim_clear(hbp, hhdr, sz, list) register struct hblk *hbp; /* ptr to current heap block */ register hdr * hhdr; -GC_bool abort_if_found; /* Abort if a reclaimable object is found */ register ptr_t list; register word sz; { @@ -105,7 +234,6 @@ register word sz; if( mark_bit_from_hdr(hhdr, word_no) ) { p += sz; } else { - FOUND_FREE(hbp, word_no); INCR_WORDS(sz); /* object is available - put on list */ obj_link(p) = list; @@ -131,10 +259,9 @@ register word sz; * A special case for 2 word composite objects (e.g. cons cells): */ /*ARGSUSED*/ -ptr_t GC_reclaim_clear2(hbp, hhdr, list, abort_if_found) +ptr_t GC_reclaim_clear2(hbp, hhdr, list) register struct hblk *hbp; /* ptr to current heap block */ hdr * hhdr; -GC_bool abort_if_found; /* Abort if a reclaimable object is found */ register ptr_t list; { register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]); @@ -146,7 +273,6 @@ register ptr_t list; register int i; # define DO_OBJ(start_displ) \ if (!(mark_word & ((word)1 << start_displ))) { \ - FOUND_FREE(hbp, p - (word *)hbp + start_displ); \ p[start_displ] = (word)list; \ list = (ptr_t)(p+start_displ); \ p[start_displ+1] = 0; \ @@ -179,10 +305,9 @@ register ptr_t list; * Another special case for 4 word composite objects: */ /*ARGSUSED*/ -ptr_t GC_reclaim_clear4(hbp, hhdr, list, abort_if_found) +ptr_t GC_reclaim_clear4(hbp, hhdr, list) register struct hblk *hbp; /* ptr to current heap block */ hdr * hhdr; -GC_bool abort_if_found; /* Abort if a reclaimable object is found */ register ptr_t list; { register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]); @@ -193,7 +318,6 @@ register ptr_t list; register word mark_word; # define DO_OBJ(start_displ) \ if (!(mark_word & ((word)1 << start_displ))) { \ - FOUND_FREE(hbp, p - (word *)hbp + start_displ); \ p[start_displ] = (word)list; \ list = (ptr_t)(p+start_displ); \ p[start_displ+1] = 0; \ @@ -239,10 +363,9 @@ register ptr_t list; /* The same thing, but don't clear objects: */ /*ARGSUSED*/ -ptr_t GC_reclaim_uninit(hbp, hhdr, sz, list, abort_if_found) +ptr_t GC_reclaim_uninit(hbp, hhdr, sz, list) register struct hblk *hbp; /* ptr to current heap block */ register hdr * hhdr; -GC_bool abort_if_found; /* Abort if a reclaimable object is found */ register ptr_t list; register word sz; { @@ -260,7 +383,6 @@ register word sz; /* go through all words in block */ while( p <= plim ) { if( !mark_bit_from_hdr(hhdr, word_no) ) { - FOUND_FREE(hbp, word_no); INCR_WORDS(sz); /* object is available - put on list */ obj_link(p) = list; @@ -275,15 +397,42 @@ register word sz; 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, abort_if_found) +ptr_t GC_reclaim_uninit2(hbp, hhdr, list) register struct hblk *hbp; /* ptr to current heap block */ hdr * hhdr; -GC_bool abort_if_found; /* Abort if a reclaimable object is found */ register ptr_t list; { register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]); @@ -295,7 +444,6 @@ register ptr_t list; register int i; # define DO_OBJ(start_displ) \ if (!(mark_word & ((word)1 << start_displ))) { \ - FOUND_FREE(hbp, p - (word *)hbp + start_displ); \ p[start_displ] = (word)list; \ list = (ptr_t)(p+start_displ); \ INCR_WORDS(2); \ @@ -327,10 +475,9 @@ register ptr_t list; * Another special case for 4 word atomic objects: */ /*ARGSUSED*/ -ptr_t GC_reclaim_uninit4(hbp, hhdr, list, abort_if_found) +ptr_t GC_reclaim_uninit4(hbp, hhdr, list) register struct hblk *hbp; /* ptr to current heap block */ hdr * hhdr; -GC_bool abort_if_found; /* Abort if a reclaimable object is found */ register ptr_t list; { register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]); @@ -341,7 +488,6 @@ register ptr_t list; register word mark_word; # define DO_OBJ(start_displ) \ if (!(mark_word & ((word)1 << start_displ))) { \ - FOUND_FREE(hbp, p - (word *)hbp + start_displ); \ p[start_displ] = (word)list; \ list = (ptr_t)(p+start_displ); \ INCR_WORDS(4); \ @@ -382,10 +528,9 @@ register ptr_t list; /* Finally the one word case, which never requires any clearing: */ /*ARGSUSED*/ -ptr_t GC_reclaim1(hbp, hhdr, list, abort_if_found) +ptr_t GC_reclaim1(hbp, hhdr, list) register struct hblk *hbp; /* ptr to current heap block */ hdr * hhdr; -GC_bool abort_if_found; /* Abort if a reclaimable object is found */ register ptr_t list; { register word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]); @@ -397,7 +542,6 @@ register ptr_t list; register int i; # define DO_OBJ(start_displ) \ if (!(mark_word & ((word)1 << start_displ))) { \ - FOUND_FREE(hbp, p - (word *)hbp + start_displ); \ p[start_displ] = (word)list; \ list = (ptr_t)(p+start_displ); \ INCR_WORDS(1); \ @@ -433,15 +577,16 @@ register ptr_t list; * If entirely empty blocks are to be completely deallocated, then * caller should perform that check. */ -void GC_reclaim_small_nonempty_block(hbp, abort_if_found) +void GC_reclaim_small_nonempty_block(hbp, report_if_found) register struct hblk *hbp; /* ptr to current heap block */ -int abort_if_found; /* Abort if a reclaimable object is found */ +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; + word sz; /* size of objects in current block */ + struct obj_kind * ok; + ptr_t * flh; + int kind; + GC_bool full; hhdr = HDR(hbp); sz = hhdr -> hb_sz; @@ -449,43 +594,70 @@ int abort_if_found; /* Abort if a reclaimable object kind = hhdr -> hb_obj_kind; ok = &GC_obj_kinds[kind]; flh = &(ok -> ok_freelist[sz]); - GC_write_hint(hbp); - if (ok -> ok_init) { + 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, abort_if_found); + full = GC_block_nearly_full1(hhdr, 0xffffffffl); + if (TRUE == full) goto out; + if (FALSE == full) GC_write_hint(hbp); + /* In the DONT_KNOW case, we let reclaim fault. */ + *flh = GC_reclaim1(hbp, hhdr, *flh); break; case 2: - *flh = GC_reclaim_clear2(hbp, hhdr, *flh, abort_if_found); + full = GC_block_nearly_full1(hhdr, 0x55555555l); + if (TRUE == full) goto out; + if (FALSE == full) GC_write_hint(hbp); + *flh = GC_reclaim_clear2(hbp, hhdr, *flh); break; case 4: - *flh = GC_reclaim_clear4(hbp, hhdr, *flh, abort_if_found); + full = GC_block_nearly_full1(hhdr, 0x11111111l); + if (TRUE == full) goto out; + if (FALSE == full) GC_write_hint(hbp); + *flh = GC_reclaim_clear4(hbp, hhdr, *flh); break; # endif default: - *flh = GC_reclaim_clear(hbp, hhdr, sz, *flh, abort_if_found); + full = GC_block_nearly_full(hhdr); + if (TRUE == full) goto out; + if (FALSE == full) GC_write_hint(hbp); + *flh = GC_reclaim_clear(hbp, hhdr, sz, *flh); break; } } else { switch(sz) { # ifndef SMALL_CONFIG case 1: - *flh = GC_reclaim1(hbp, hhdr, *flh, abort_if_found); + full = GC_block_nearly_full1(hhdr, 0xffffffffl); + if (TRUE == full) goto out; + if (FALSE == full) GC_write_hint(hbp); + *flh = GC_reclaim1(hbp, hhdr, *flh); break; case 2: - *flh = GC_reclaim_uninit2(hbp, hhdr, *flh, abort_if_found); + full = GC_block_nearly_full1(hhdr, 0x55555555l); + if (TRUE == full) goto out; + if (FALSE == full) GC_write_hint(hbp); + *flh = GC_reclaim_uninit2(hbp, hhdr, *flh); break; case 4: - *flh = GC_reclaim_uninit4(hbp, hhdr, *flh, abort_if_found); + full = GC_block_nearly_full1(hhdr, 0x11111111l); + if (TRUE == full) goto out; + if (FALSE == full) GC_write_hint(hbp); + *flh = GC_reclaim_uninit4(hbp, hhdr, *flh); break; # endif default: - *flh = GC_reclaim_uninit(hbp, hhdr, sz, *flh, abort_if_found); + full = GC_block_nearly_full(hhdr); + if (TRUE == full) goto out; + if (FALSE == full) GC_write_hint(hbp); + *flh = GC_reclaim_uninit(hbp, hhdr, sz, *flh); break; } } +out: if (IS_UNCOLLECTABLE(kind)) GC_set_hdr_marks(hhdr); } @@ -494,11 +666,12 @@ int abort_if_found; /* Abort if a reclaimable object * to the heap block free list. * Otherwise enqueue the block for later processing * by GC_reclaim_small_nonempty_block. - * If abort_if_found is TRUE, then process any block immediately. + * 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, abort_if_found) +void GC_reclaim_block(hbp, report_if_found) register struct hblk *hbp; /* ptr to current heap block */ -word abort_if_found; /* Abort if a reclaimable object is found */ +word report_if_found; /* Abort if a reclaimable object is found */ { register hdr * hhdr; register word sz; /* size of objects in current block */ @@ -511,16 +684,19 @@ word abort_if_found; /* Abort if a reclaimable object if( sz > MAXOBJSZ ) { /* 1 big object */ if( !mark_bit_from_hdr(hhdr, HDR_WORDS) ) { - FOUND_FREE(hbp, HDR_WORDS); -# ifdef GATHERSTATS + if (report_if_found) { + FOUND_FREE(hbp, HDR_WORDS); + } else { +# ifdef GATHERSTATS GC_mem_found += sz; -# endif - GC_freehblk(hbp); +# endif + GC_freehblk(hbp); + } } } else { GC_bool empty = GC_block_empty(hhdr); - if (abort_if_found) { - GC_reclaim_small_nonempty_block(hbp, (int)abort_if_found); + 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); @@ -600,11 +776,11 @@ void GC_print_block_list() #endif /* NO_DEBUGGING */ /* - * Do the same thing on the entire heap, after first clearing small object - * free lists (if we are not just looking for leaks). + * 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(abort_if_found) -int abort_if_found; /* Abort if a GC_reclaimable object is found */ +void GC_start_reclaim(report_if_found) +int report_if_found; /* Abort if a GC_reclaimable object is found */ { int kind; @@ -617,7 +793,7 @@ int abort_if_found; /* Abort if a GC_reclaimable obje register struct hblk ** rlist = GC_obj_kinds[kind].ok_reclaim_list; if (rlist == 0) continue; /* This kind not used. */ - if (!abort_if_found) { + 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; @@ -637,7 +813,7 @@ int abort_if_found; /* Abort if a GC_reclaimable obje /* 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)abort_if_found); + GC_apply_to_all_blocks(GC_reclaim_block, (word)report_if_found); }