Annotation of OpenXM_contrib2/asir2000/gc/include/private/gc_pmark.h, Revision 1.4
1.1 noro 1: /*
2: * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
3: * Copyright (c) 2001 by Hewlett-Packard Company. All rights reserved.
4: *
5: * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
6: * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
7: *
8: * Permission is hereby granted to use or copy this program
9: * for any purpose, provided the above notices are retained on all copies.
10: * Permission to modify the code and to distribute modified code is granted,
11: * provided the above notices are retained, and a notice that the code was
12: * modified is included with the above copyright notice.
13: *
14: */
15:
16: /* Private declarations of GC marker data structures and macros */
17:
18: /*
19: * Declarations of mark stack. Needed by marker and client supplied mark
20: * routines. Transitively include gc_priv.h.
21: * (Note that gc_priv.h should not be included before this, since this
22: * includes dbg_mlc.h, which wants to include gc_priv.h AFTER defining
23: * I_HIDE_POINTERS.)
24: */
25: #ifndef GC_PMARK_H
26: # define GC_PMARK_H
27:
1.3 noro 28: # if defined(KEEP_BACK_PTRS) || defined(PRINT_BLACK_LIST)
1.1 noro 29: # include "dbg_mlc.h"
30: # endif
31: # ifndef GC_MARK_H
32: # include "../gc_mark.h"
33: # endif
34: # ifndef GC_PRIVATE_H
35: # include "gc_priv.h"
36: # endif
37:
38: /* The real declarations of the following is in gc_priv.h, so that */
39: /* we can avoid scanning the following table. */
40: /*
41: extern mark_proc GC_mark_procs[MAX_MARK_PROCS];
42: */
43:
44: /*
45: * Mark descriptor stuff that should remain private for now, mostly
46: * because it's hard to export WORDSZ without including gcconfig.h.
47: */
48: # define BITMAP_BITS (WORDSZ - GC_DS_TAG_BITS)
49: # define PROC(descr) \
50: (GC_mark_procs[((descr) >> GC_DS_TAG_BITS) & (GC_MAX_MARK_PROCS-1)])
51: # define ENV(descr) \
52: ((descr) >> (GC_DS_TAG_BITS + GC_LOG_MAX_MARK_PROCS))
53: # define MAX_ENV \
54: (((word)1 << (WORDSZ - GC_DS_TAG_BITS - GC_LOG_MAX_MARK_PROCS)) - 1)
55:
56:
57: extern word GC_n_mark_procs;
58:
59: /* Number of mark stack entries to discard on overflow. */
60: #define GC_MARK_STACK_DISCARDS (INITIAL_MARK_STACK_SIZE/8)
61:
62: typedef struct GC_ms_entry {
63: GC_word * mse_start; /* First word of object */
64: GC_word mse_descr; /* Descriptor; low order two bits are tags, */
65: /* identifying the upper 30 bits as one of the */
66: /* following: */
67: } mse;
68:
69: extern word GC_mark_stack_size;
70:
71: extern mse * GC_mark_stack_limit;
72:
73: #ifdef PARALLEL_MARK
74: extern mse * VOLATILE GC_mark_stack_top;
75: #else
76: extern mse * GC_mark_stack_top;
77: #endif
78:
79: extern mse * GC_mark_stack;
80:
81: #ifdef PARALLEL_MARK
82: /*
83: * Allow multiple threads to participate in the marking process.
84: * This works roughly as follows:
85: * The main mark stack never shrinks, but it can grow.
86: *
87: * The initiating threads holds the GC lock, and sets GC_help_wanted.
88: *
89: * Other threads:
90: * 1) update helper_count (while holding mark_lock.)
91: * 2) allocate a local mark stack
92: * repeatedly:
93: * 3) Steal a global mark stack entry by atomically replacing
94: * its descriptor with 0.
95: * 4) Copy it to the local stack.
96: * 5) Mark on the local stack until it is empty, or
97: * it may be profitable to copy it back.
98: * 6) If necessary, copy local stack to global one,
99: * holding mark lock.
100: * 7) Stop when the global mark stack is empty.
101: * 8) decrement helper_count (holding mark_lock).
102: *
103: * This is an experiment to see if we can do something along the lines
104: * of the University of Tokyo SGC in a less intrusive, though probably
105: * also less performant, way.
106: */
107: void GC_do_parallel_mark();
108: /* inititate parallel marking. */
109:
110: extern GC_bool GC_help_wanted; /* Protected by mark lock */
111: extern unsigned GC_helper_count; /* Number of running helpers. */
112: /* Protected by mark lock */
113: extern unsigned GC_active_count; /* Number of active helpers. */
114: /* Protected by mark lock */
115: /* May increase and decrease */
116: /* within each mark cycle. But */
117: /* once it returns to 0, it */
118: /* stays zero for the cycle. */
119: /* GC_mark_stack_top is also protected by mark lock. */
120: extern mse * VOLATILE GC_first_nonempty;
121: /* Lowest entry on mark stack */
122: /* that may be nonempty. */
123: /* Updated only by initiating */
124: /* thread. */
125: /*
126: * GC_notify_all_marker() is used when GC_help_wanted is first set,
127: * when the last helper becomes inactive,
128: * when something is added to the global mark stack, and just after
129: * GC_mark_no is incremented.
130: * This could be split into multiple CVs (and probably should be to
131: * scale to really large numbers of processors.)
132: */
133: #endif /* PARALLEL_MARK */
134:
1.3 noro 135: /* Return a pointer to within 1st page of object. */
136: /* Set *new_hdr_p to corr. hdr. */
137: #ifdef __STDC__
138: # ifdef PRINT_BLACK_LIST
139: ptr_t GC_find_start(ptr_t current, hdr *hhdr, hdr **new_hdr_p,
140: word source);
141: # else
142: ptr_t GC_find_start(ptr_t current, hdr *hhdr, hdr **new_hdr_p);
143: # endif
144: #else
145: ptr_t GC_find_start();
146: #endif
1.1 noro 147:
1.3 noro 148: mse * GC_signal_mark_stack_overflow GC_PROTO((mse *msp));
1.1 noro 149:
150: # ifdef GATHERSTATS
151: # define ADD_TO_ATOMIC(sz) GC_atomic_in_use += (sz)
152: # define ADD_TO_COMPOSITE(sz) GC_composite_in_use += (sz)
153: # else
154: # define ADD_TO_ATOMIC(sz)
155: # define ADD_TO_COMPOSITE(sz)
156: # endif
157:
158: /* Push the object obj with corresponding heap block header hhdr onto */
159: /* the mark stack. */
160: # define PUSH_OBJ(obj, hhdr, mark_stack_top, mark_stack_limit) \
161: { \
162: register word _descr = (hhdr) -> hb_descr; \
163: \
164: if (_descr == 0) { \
165: ADD_TO_ATOMIC((hhdr) -> hb_sz); \
166: } else { \
167: ADD_TO_COMPOSITE((hhdr) -> hb_sz); \
168: mark_stack_top++; \
169: if (mark_stack_top >= mark_stack_limit) { \
170: mark_stack_top = GC_signal_mark_stack_overflow(mark_stack_top); \
171: } \
172: mark_stack_top -> mse_start = (obj); \
173: mark_stack_top -> mse_descr = _descr; \
174: } \
175: }
176:
177: /* Push the contents of current onto the mark stack if it is a valid */
178: /* ptr to a currently unmarked object. Mark it. */
179: /* If we assumed a standard-conforming compiler, we could probably */
180: /* generate the exit_label transparently. */
181: # define PUSH_CONTENTS(current, mark_stack_top, mark_stack_limit, \
182: source, exit_label) \
183: { \
184: hdr * my_hhdr; \
185: ptr_t my_current = current; \
186: \
187: GET_HDR(my_current, my_hhdr); \
188: if (IS_FORWARDING_ADDR_OR_NIL(my_hhdr)) { \
1.3 noro 189: hdr * new_hdr = GC_invalid_header; \
190: my_current = GC_find_start(my_current, my_hhdr, &new_hdr); \
191: my_hhdr = new_hdr; \
1.1 noro 192: } \
193: PUSH_CONTENTS_HDR(my_current, mark_stack_top, mark_stack_limit, \
194: source, exit_label, my_hhdr); \
195: exit_label: ; \
196: }
197:
198: /* As above, but use header cache for header lookup. */
199: # define HC_PUSH_CONTENTS(current, mark_stack_top, mark_stack_limit, \
200: source, exit_label) \
201: { \
202: hdr * my_hhdr; \
203: ptr_t my_current = current; \
204: \
205: HC_GET_HDR(my_current, my_hhdr, source); \
206: PUSH_CONTENTS_HDR(my_current, mark_stack_top, mark_stack_limit, \
207: source, exit_label, my_hhdr); \
208: exit_label: ; \
209: }
210:
211: /* Set mark bit, exit if it was already set. */
212:
213: # ifdef USE_MARK_BYTES
214: /* Unlike the mark bit case, there is a race here, and we may set */
215: /* the bit twice in the concurrent case. This can result in the */
216: /* object being pushed twice. But that's only a performance issue. */
217: # define SET_MARK_BIT_EXIT_IF_SET(hhdr,displ,exit_label) \
218: { \
219: register VOLATILE char * mark_byte_addr = \
220: hhdr -> hb_marks + ((displ) >> 1); \
221: register char mark_byte = *mark_byte_addr; \
222: \
223: if (mark_byte) goto exit_label; \
224: *mark_byte_addr = 1; \
225: }
226: # else
227: # define SET_MARK_BIT_EXIT_IF_SET(hhdr,displ,exit_label) \
228: { \
229: register word * mark_word_addr = hhdr -> hb_marks + divWORDSZ(displ); \
230: \
231: OR_WORD_EXIT_IF_SET(mark_word_addr, (word)1 << modWORDSZ(displ), \
232: exit_label); \
233: }
234: # endif /* USE_MARK_BYTES */
235:
236: /* If the mark bit corresponding to current is not set, set it, and */
1.3 noro 237: /* push the contents of the object on the mark stack. For a small */
238: /* object we assume that current is the (possibly interior) pointer */
239: /* to the object. For large objects we assume that current points */
240: /* to somewhere inside the first page of the object. If */
241: /* GC_all_interior_pointers is set, it may have been previously */
242: /* adjusted to make that true. */
1.1 noro 243: # define PUSH_CONTENTS_HDR(current, mark_stack_top, mark_stack_limit, \
244: source, exit_label, hhdr) \
245: { \
246: int displ; /* Displacement in block; first bytes, then words */ \
247: int map_entry; \
248: \
249: displ = HBLKDISPL(current); \
250: map_entry = MAP_ENTRY((hhdr -> hb_map), displ); \
251: displ = BYTES_TO_WORDS(displ); \
252: if (map_entry > CPP_MAX_OFFSET) { \
253: if (map_entry == OFFSET_TOO_BIG) { \
254: map_entry = displ % (hhdr -> hb_sz); \
255: displ -= map_entry; \
256: if (displ + (hhdr -> hb_sz) > BYTES_TO_WORDS(HBLKSIZE)) { \
257: GC_ADD_TO_BLACK_LIST_NORMAL((word)current, source); \
258: goto exit_label; \
259: } \
260: } else { \
261: GC_ADD_TO_BLACK_LIST_NORMAL((word)current, source); goto exit_label; \
262: } \
263: } else { \
264: displ -= map_entry; \
265: } \
266: GC_ASSERT(displ >= 0 && displ < MARK_BITS_PER_HBLK); \
267: SET_MARK_BIT_EXIT_IF_SET(hhdr, displ, exit_label); \
268: GC_STORE_BACK_PTR((ptr_t)source, (ptr_t)HBLKPTR(current) \
269: + WORDS_TO_BYTES(displ)); \
270: PUSH_OBJ(((word *)(HBLKPTR(current)) + displ), hhdr, \
271: mark_stack_top, mark_stack_limit) \
272: }
273:
274: #if defined(PRINT_BLACK_LIST) || defined(KEEP_BACK_PTRS)
275: # define PUSH_ONE_CHECKED_STACK(p, source) \
276: GC_mark_and_push_stack(p, (ptr_t)(source))
277: #else
278: # define PUSH_ONE_CHECKED_STACK(p, source) \
279: GC_mark_and_push_stack(p)
280: #endif
281:
282: /*
283: * Push a single value onto mark stack. Mark from the object pointed to by p.
1.4 ! noro 284: * Invoke FIXUP_POINTER(p) before any further processing.
1.1 noro 285: * P is considered valid even if it is an interior pointer.
286: * Previously marked objects are not pushed. Hence we make progress even
287: * if the mark stack overflows.
288: */
1.4 ! noro 289:
! 290: # if NEED_FIXUP_POINTER
! 291: /* Try both the raw version and the fixed up one. */
! 292: # define GC_PUSH_ONE_STACK(p, source) \
! 293: if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr \
! 294: && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
! 295: PUSH_ONE_CHECKED_STACK(p, source); \
! 296: } \
! 297: FIXUP_POINTER(p); \
! 298: if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr \
1.1 noro 299: && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
300: PUSH_ONE_CHECKED_STACK(p, source); \
1.4 ! noro 301: }
! 302: # else /* !NEED_FIXUP_POINTER */
! 303: # define GC_PUSH_ONE_STACK(p, source) \
! 304: if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr \
! 305: && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
! 306: PUSH_ONE_CHECKED_STACK(p, source); \
! 307: }
! 308: # endif
! 309:
1.1 noro 310:
311: /*
312: * As above, but interior pointer recognition as for
313: * normal for heap pointers.
314: */
315: # define GC_PUSH_ONE_HEAP(p,source) \
1.4 ! noro 316: FIXUP_POINTER(p); \
1.1 noro 317: if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr \
318: && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) { \
319: GC_mark_stack_top = GC_mark_and_push( \
320: (GC_PTR)(p), GC_mark_stack_top, \
321: GC_mark_stack_limit, (GC_PTR *)(source)); \
322: }
323:
324: /* Mark starting at mark stack entry top (incl.) down to */
325: /* mark stack entry bottom (incl.). Stop after performing */
326: /* about one page worth of work. Return the new mark stack */
327: /* top entry. */
328: mse * GC_mark_from GC_PROTO((mse * top, mse * bottom, mse *limit));
329:
330: #define MARK_FROM_MARK_STACK() \
331: GC_mark_stack_top = GC_mark_from(GC_mark_stack_top, \
332: GC_mark_stack, \
333: GC_mark_stack + GC_mark_stack_size);
334:
335: /*
336: * Mark from one finalizable object using the specified
337: * mark proc. May not mark the object pointed to by
338: * real_ptr. That is the job of the caller, if appropriate
339: */
340: # define GC_MARK_FO(real_ptr, mark_proc) \
341: { \
342: (*(mark_proc))(real_ptr); \
343: while (!GC_mark_stack_empty()) MARK_FROM_MARK_STACK(); \
344: if (GC_mark_state != MS_NONE) { \
345: GC_set_mark_bit(real_ptr); \
1.3 noro 346: while (!GC_mark_some((ptr_t)0)) {} \
1.1 noro 347: } \
348: }
349:
350: extern GC_bool GC_mark_stack_too_small;
351: /* We need a larger mark stack. May be */
352: /* set by client supplied mark routines.*/
353:
354: typedef int mark_state_t; /* Current state of marking, as follows:*/
355: /* Used to remember where we are during */
356: /* concurrent marking. */
357:
358: /* We say something is dirty if it was */
359: /* written since the last time we */
360: /* retrieved dirty bits. We say it's */
361: /* grungy if it was marked dirty in the */
362: /* last set of bits we retrieved. */
363:
364: /* Invariant I: all roots and marked */
365: /* objects p are either dirty, or point */
366: /* to objects q that are either marked */
367: /* or a pointer to q appears in a range */
368: /* on the mark stack. */
369:
370: # define MS_NONE 0 /* No marking in progress. I holds. */
371: /* Mark stack is empty. */
372:
373: # define MS_PUSH_RESCUERS 1 /* Rescuing objects are currently */
374: /* being pushed. I holds, except */
375: /* that grungy roots may point to */
376: /* unmarked objects, as may marked */
377: /* grungy objects above scan_ptr. */
378:
379: # define MS_PUSH_UNCOLLECTABLE 2
380: /* I holds, except that marked */
381: /* uncollectable objects above scan_ptr */
382: /* may point to unmarked objects. */
383: /* Roots may point to unmarked objects */
384:
385: # define MS_ROOTS_PUSHED 3 /* I holds, mark stack may be nonempty */
386:
387: # define MS_PARTIALLY_INVALID 4 /* I may not hold, e.g. because of M.S. */
388: /* overflow. However marked heap */
389: /* objects below scan_ptr point to */
390: /* marked or stacked objects. */
391:
392: # define MS_INVALID 5 /* I may not hold. */
393:
394: extern mark_state_t GC_mark_state;
395:
396: #endif /* GC_PMARK_H */
397:
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