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-rw-r--r--mark.c725
1 files changed, 569 insertions, 156 deletions
diff --git a/mark.c b/mark.c
index c54d894..4d75047 100644
--- a/mark.c
+++ b/mark.c
@@ -2,6 +2,7 @@
/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
+ * Copyright (c) 2000 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.
@@ -16,8 +17,7 @@
# include <stdio.h>
-# include "gc_priv.h"
-# include "gc_mark.h"
+# include "private/gc_pmark.h"
/* We put this here to minimize the risk of inlining. */
/*VARARGS*/
@@ -46,25 +46,21 @@ word GC_n_mark_procs = GC_RESERVED_MARK_PROCS;
/* It's done here, since we need to deal with mark descriptors. */
struct obj_kind GC_obj_kinds[MAXOBJKINDS] = {
/* PTRFREE */ { &GC_aobjfreelist[0], 0 /* filled in dynamically */,
- 0 | DS_LENGTH, FALSE, FALSE },
+ 0 | GC_DS_LENGTH, FALSE, FALSE },
/* NORMAL */ { &GC_objfreelist[0], 0,
-# if defined(ADD_BYTE_AT_END) && ALIGNMENT > DS_TAGS
- (word)(-ALIGNMENT) | DS_LENGTH,
-# else
- 0 | DS_LENGTH,
-# endif
+ 0 | GC_DS_LENGTH, /* Adjusted in GC_init_inner for EXTRA_BYTES */
TRUE /* add length to descr */, TRUE },
/* UNCOLLECTABLE */
{ &GC_uobjfreelist[0], 0,
- 0 | DS_LENGTH, TRUE /* add length to descr */, TRUE },
+ 0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
# ifdef ATOMIC_UNCOLLECTABLE
/* AUNCOLLECTABLE */
{ &GC_auobjfreelist[0], 0,
- 0 | DS_LENGTH, FALSE /* add length to descr */, FALSE },
+ 0 | GC_DS_LENGTH, FALSE /* add length to descr */, FALSE },
# endif
# ifdef STUBBORN_ALLOC
/*STUBBORN*/ { &GC_sobjfreelist[0], 0,
- 0 | DS_LENGTH, TRUE /* add length to descr */, TRUE },
+ 0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
# endif
};
@@ -104,9 +100,15 @@ word GC_n_rescuing_pages; /* Number of dirty pages we marked from */
mse * GC_mark_stack;
+mse * GC_mark_stack_limit;
+
word GC_mark_stack_size = 0;
-mse * GC_mark_stack_top;
+#ifdef PARALLEL_MARK
+ mse * VOLATILE GC_mark_stack_top;
+#else
+ mse * GC_mark_stack_top;
+#endif
static struct hblk * scan_ptr;
@@ -129,7 +131,11 @@ GC_bool GC_collection_in_progress()
void GC_clear_hdr_marks(hhdr)
register hdr * hhdr;
{
- BZERO(hhdr -> hb_marks, MARK_BITS_SZ*sizeof(word));
+# ifdef USE_MARK_BYTES
+ BZERO(hhdr -> hb_marks, MARK_BITS_SZ);
+# else
+ BZERO(hhdr -> hb_marks, MARK_BITS_SZ*sizeof(word));
+# endif
}
/* Set all mark bits in the header. Used for uncollectable blocks. */
@@ -139,7 +145,11 @@ register hdr * hhdr;
register int i;
for (i = 0; i < MARK_BITS_SZ; ++i) {
+# ifdef USE_MARK_BYTES
+ hhdr -> hb_marks[i] = 1;
+# else
hhdr -> hb_marks[i] = ONES;
+# endif
}
}
@@ -147,9 +157,13 @@ register hdr * hhdr;
* Clear all mark bits associated with block h.
*/
/*ARGSUSED*/
-static void clear_marks_for_block(h, dummy)
-struct hblk *h;
-word dummy;
+# if defined(__STDC__) || defined(__cplusplus)
+ static void clear_marks_for_block(struct hblk *h, word dummy)
+# else
+ static void clear_marks_for_block(h, dummy)
+ struct hblk *h;
+ word dummy;
+# endif
{
register hdr * hhdr = HDR(h);
@@ -227,9 +241,7 @@ void GC_initiate_gc()
if (GC_dirty_maintained) GC_check_dirty();
}
# endif
-# ifdef GATHERSTATS
- GC_n_rescuing_pages = 0;
-# endif
+ GC_n_rescuing_pages = 0;
if (GC_mark_state == MS_NONE) {
GC_mark_state = MS_PUSH_RESCUERS;
} else if (GC_mark_state != MS_INVALID) {
@@ -269,20 +281,21 @@ ptr_t cold_gc_frame;
case MS_PUSH_RESCUERS:
if (GC_mark_stack_top
- >= GC_mark_stack + GC_mark_stack_size
- - INITIAL_MARK_STACK_SIZE/2) {
+ >= GC_mark_stack_limit - INITIAL_MARK_STACK_SIZE/2) {
/* Go ahead and mark, even though that might cause us to */
/* see more marked dirty objects later on. Avoid this */
/* in the future. */
GC_mark_stack_too_small = TRUE;
- GC_mark_from_mark_stack();
+ MARK_FROM_MARK_STACK();
return(FALSE);
} else {
scan_ptr = GC_push_next_marked_dirty(scan_ptr);
if (scan_ptr == 0) {
-# ifdef PRINTSTATS
+# ifdef CONDPRINT
+ if (GC_print_stats) {
GC_printf1("Marked from %lu dirty pages\n",
(unsigned long)GC_n_rescuing_pages);
+ }
# endif
GC_push_roots(FALSE, cold_gc_frame);
GC_objects_are_marked = TRUE;
@@ -295,8 +308,13 @@ ptr_t cold_gc_frame;
case MS_PUSH_UNCOLLECTABLE:
if (GC_mark_stack_top
- >= GC_mark_stack + INITIAL_MARK_STACK_SIZE/4) {
- GC_mark_from_mark_stack();
+ >= GC_mark_stack + GC_mark_stack_size/4) {
+# ifdef PARALLEL_MARK
+ /* Avoid this, since we don't parallelize the marker */
+ /* here. */
+ if (GC_parallel) GC_mark_stack_too_small = TRUE;
+# endif
+ MARK_FROM_MARK_STACK();
return(FALSE);
} else {
scan_ptr = GC_push_next_marked_uncollectable(scan_ptr);
@@ -311,8 +329,32 @@ ptr_t cold_gc_frame;
return(FALSE);
case MS_ROOTS_PUSHED:
+# ifdef PARALLEL_MARK
+ /* In the incremental GC case, this currently doesn't */
+ /* quite do the right thing, since it runs to */
+ /* completion. On the other hand, starting a */
+ /* parallel marker is expensive, so perhaps it is */
+ /* the right thing? */
+ /* Eventually, incremental marking should run */
+ /* asynchronously in multiple threads, without grabbing */
+ /* the allocation lock. */
+ if (GC_parallel) {
+ GC_do_parallel_mark();
+ GC_ASSERT(GC_mark_stack_top < GC_first_nonempty);
+ GC_mark_stack_top = GC_mark_stack - 1;
+ if (GC_mark_stack_too_small) {
+ alloc_mark_stack(2*GC_mark_stack_size);
+ }
+ if (GC_mark_state == MS_ROOTS_PUSHED) {
+ GC_mark_state = MS_NONE;
+ return(TRUE);
+ } else {
+ return(FALSE);
+ }
+ }
+# endif
if (GC_mark_stack_top >= GC_mark_stack) {
- GC_mark_from_mark_stack();
+ MARK_FROM_MARK_STACK();
return(FALSE);
} else {
GC_mark_state = MS_NONE;
@@ -329,7 +371,7 @@ ptr_t cold_gc_frame;
return(FALSE);
}
if (GC_mark_stack_top >= GC_mark_stack) {
- GC_mark_from_mark_stack();
+ MARK_FROM_MARK_STACK();
return(FALSE);
}
if (scan_ptr == 0 && GC_mark_state == MS_INVALID) {
@@ -356,10 +398,12 @@ ptr_t cold_gc_frame;
#ifdef MSWIN32
} __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
-# ifdef PRINTSTATS
+# ifdef CONDPRINT
+ if (GC_print_stats) {
GC_printf0("Caught ACCESS_VIOLATION in marker. "
"Memory mapping disappeared.\n");
-# endif /* PRINTSTATS */
+ }
+# endif /* CONDPRINT */
/* We have bad roots on the stack. Discard mark stack. */
/* Rescan from marked objects. Redetermine roots. */
GC_invalidate_mark_state();
@@ -383,27 +427,28 @@ GC_bool GC_mark_stack_empty()
#endif
/* Given a pointer to someplace other than a small object page or the */
-/* first page of a large object, return a pointer either to the */
-/* start of the large object or NIL. */
-/* In the latter case black list the address current. */
-/* Returns NIL without black listing if current points to a block */
-/* with IGNORE_OFF_PAGE set. */
+/* first page of a large object, either: */
+/* - return a pointer to somewhere in the first page of the large */
+/* object, if current points to a large object. */
+/* In this case *hhdr is replaced with a pointer to the header */
+/* for the large object. */
+/* - just return current if it does not point to a large object. */
/*ARGSUSED*/
# ifdef PRINT_BLACK_LIST
- ptr_t GC_find_start(current, hhdr, source)
- word source;
+ ptr_t GC_find_start(current, hhdr, new_hdr_p, source)
+ ptr_t source;
# else
- ptr_t GC_find_start(current, hhdr)
+ ptr_t GC_find_start(current, hhdr, new_hdr_p)
# define source 0
# endif
register ptr_t current;
-register hdr * hhdr;
+register hdr *hhdr, **new_hdr_p;
{
-# ifdef ALL_INTERIOR_POINTERS
+ if (GC_all_interior_pointers) {
if (hhdr != 0) {
register ptr_t orig = current;
- current = (ptr_t)HBLKPTR(current) + HDR_BYTES;
+ current = (ptr_t)HBLKPTR(current);
do {
current = current - HBLKSIZE*(word)hhdr;
hhdr = HDR(current);
@@ -413,18 +458,16 @@ register hdr * hhdr;
if ((word *)orig - (word *)current
>= (ptrdiff_t)(hhdr->hb_sz)) {
/* Pointer past the end of the block */
- GC_ADD_TO_BLACK_LIST_NORMAL(orig, source);
- return(0);
+ return(orig);
}
+ *new_hdr_p = hhdr;
return(current);
} else {
- GC_ADD_TO_BLACK_LIST_NORMAL(current, source);
- return(0);
+ return(current);
}
-# else
- GC_ADD_TO_BLACK_LIST_NORMAL(current, source);
- return(0);
-# endif
+ } else {
+ return(current);
+ }
# undef source
}
@@ -439,14 +482,15 @@ mse * msp;
{
GC_mark_state = MS_INVALID;
GC_mark_stack_too_small = TRUE;
-# ifdef PRINTSTATS
+# ifdef CONDPRINT
+ if (GC_print_stats) {
GC_printf1("Mark stack overflow; current size = %lu entries\n",
GC_mark_stack_size);
-# endif
- return(msp-INITIAL_MARK_STACK_SIZE/8);
+ }
+# endif
+ return(msp - GC_MARK_STACK_DISCARDS);
}
-
/*
* Mark objects pointed to by the regions described by
* mark stack entries between GC_mark_stack and GC_mark_stack_top,
@@ -461,11 +505,11 @@ mse * msp;
* encoding, we optionally maintain a cache for the block address to
* header mapping, we prefetch when an object is "grayed", etc.
*/
-void GC_mark_from_mark_stack()
+mse * GC_mark_from(mark_stack_top, mark_stack, mark_stack_limit)
+mse * mark_stack_top;
+mse * mark_stack;
+mse * mark_stack_limit;
{
- mse * GC_mark_stack_reg = GC_mark_stack;
- mse * GC_mark_stack_top_reg = GC_mark_stack_top;
- mse * mark_stack_limit = &(GC_mark_stack[GC_mark_stack_size]);
int credit = HBLKSIZE; /* Remaining credit for marking work */
register word * current_p; /* Pointer to current candidate ptr. */
register word current; /* Candidate pointer. */
@@ -481,45 +525,62 @@ void GC_mark_from_mark_stack()
GC_objects_are_marked = TRUE;
INIT_HDR_CACHE;
# ifdef OS2 /* Use untweaked version to circumvent compiler problem */
- while (GC_mark_stack_top_reg >= GC_mark_stack_reg && credit >= 0) {
+ while (mark_stack_top >= mark_stack && credit >= 0) {
# else
- while ((((ptr_t)GC_mark_stack_top_reg - (ptr_t)GC_mark_stack_reg) | credit)
+ while ((((ptr_t)mark_stack_top - (ptr_t)mark_stack) | credit)
>= 0) {
# endif
- current_p = GC_mark_stack_top_reg -> mse_start;
- descr = GC_mark_stack_top_reg -> mse_descr;
+ current_p = mark_stack_top -> mse_start;
+ descr = mark_stack_top -> mse_descr;
retry:
/* current_p and descr describe the current object. */
- /* *GC_mark_stack_top_reg is vacant. */
+ /* *mark_stack_top is vacant. */
/* The following is 0 only for small objects described by a simple */
/* length descriptor. For many applications this is the common */
/* case, so we try to detect it quickly. */
- if (descr & ((~(WORDS_TO_BYTES(SPLIT_RANGE_WORDS) - 1)) | DS_TAGS)) {
- word tag = descr & DS_TAGS;
+ if (descr & ((~(WORDS_TO_BYTES(SPLIT_RANGE_WORDS) - 1)) | GC_DS_TAGS)) {
+ word tag = descr & GC_DS_TAGS;
switch(tag) {
- case DS_LENGTH:
+ case GC_DS_LENGTH:
/* Large length. */
/* Process part of the range to avoid pushing too much on the */
/* stack. */
- GC_mark_stack_top_reg -> mse_start =
+# ifdef PARALLEL_MARK
+# define SHARE_BYTES 2048
+ if (descr > SHARE_BYTES && GC_parallel
+ && mark_stack_top < mark_stack_limit - 1) {
+ int new_size = (descr/2) & ~(sizeof(word)-1);
+ GC_ASSERT(descr < GC_greatest_plausible_heap_addr
+ - GC_least_plausible_heap_addr);
+ mark_stack_top -> mse_start = current_p;
+ mark_stack_top -> mse_descr = new_size + sizeof(word);
+ /* makes sure we handle */
+ /* misaligned pointers. */
+ mark_stack_top++;
+ current_p = (word *) ((char *)current_p + new_size);
+ descr -= new_size;
+ goto retry;
+ }
+# endif /* PARALLEL_MARK */
+ mark_stack_top -> mse_start =
limit = current_p + SPLIT_RANGE_WORDS-1;
- GC_mark_stack_top_reg -> mse_descr =
+ mark_stack_top -> mse_descr =
descr - WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
/* Make sure that pointers overlapping the two ranges are */
/* considered. */
limit = (word *)((char *)limit + sizeof(word) - ALIGNMENT);
break;
- case DS_BITMAP:
- GC_mark_stack_top_reg--;
- descr &= ~DS_TAGS;
+ case GC_DS_BITMAP:
+ mark_stack_top--;
+ descr &= ~GC_DS_TAGS;
credit -= WORDS_TO_BYTES(WORDSZ/2); /* guess */
while (descr != 0) {
if ((signed_word)descr < 0) {
current = *current_p;
if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
PREFETCH(current);
- HC_PUSH_CONTENTS((ptr_t)current, GC_mark_stack_top_reg,
+ HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
mark_stack_limit, current_p, exit1);
}
}
@@ -527,18 +588,18 @@ void GC_mark_from_mark_stack()
++ current_p;
}
continue;
- case DS_PROC:
- GC_mark_stack_top_reg--;
- credit -= PROC_BYTES;
- GC_mark_stack_top_reg =
+ case GC_DS_PROC:
+ mark_stack_top--;
+ credit -= GC_PROC_BYTES;
+ mark_stack_top =
(*PROC(descr))
- (current_p, GC_mark_stack_top_reg,
+ (current_p, mark_stack_top,
mark_stack_limit, ENV(descr));
continue;
- case DS_PER_OBJECT:
+ case GC_DS_PER_OBJECT:
if ((signed_word)descr >= 0) {
/* Descriptor is in the object. */
- descr = *(word *)((ptr_t)current_p + descr - DS_PER_OBJECT);
+ descr = *(word *)((ptr_t)current_p + descr - GC_DS_PER_OBJECT);
} else {
/* Descriptor is in type descriptor pointed to by first */
/* word in object. */
@@ -552,23 +613,27 @@ void GC_mark_from_mark_stack()
/* object case explicitly. */
if (0 == type_descr) {
/* Rarely executed. */
- GC_mark_stack_top_reg--;
+ mark_stack_top--;
continue;
}
descr = *(word *)(type_descr
- - (descr - (DS_PER_OBJECT - INDIR_PER_OBJ_BIAS)));
+ - (descr - (GC_DS_PER_OBJECT
+ - GC_INDIR_PER_OBJ_BIAS)));
}
if (0 == descr) {
- GC_mark_stack_top_reg--;
- continue;
+ /* Can happen either because we generated a 0 descriptor */
+ /* or we saw a pointer to a free object. */
+ mark_stack_top--;
+ continue;
}
goto retry;
}
} else /* Small object with length descriptor */ {
- GC_mark_stack_top_reg--;
+ mark_stack_top--;
limit = (word *)(((ptr_t)current_p) + (word)descr);
}
/* The simple case in which we're scanning a range. */
+ GC_ASSERT(!((word)current_p & (ALIGNMENT-1)));
credit -= (ptr_t)limit - (ptr_t)current_p;
limit -= 1;
{
@@ -585,6 +650,7 @@ void GC_mark_from_mark_stack()
/* for this loop is still not great. */
for(;;) {
PREFETCH((ptr_t)limit - PREF_DIST*CACHE_LINE_SIZE);
+ GC_ASSERT(limit >= current_p);
deferred = *limit;
limit = (word *)((char *)limit - ALIGNMENT);
if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
@@ -614,7 +680,7 @@ void GC_mark_from_mark_stack()
/* Prefetch the contents of the object we just pushed. It's */
/* likely we will need them soon. */
PREFETCH(current);
- HC_PUSH_CONTENTS((ptr_t)current, GC_mark_stack_top_reg,
+ HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
mark_stack_limit, current_p, exit2);
}
current_p = (word *)((char *)current_p + ALIGNMENT);
@@ -624,27 +690,337 @@ void GC_mark_from_mark_stack()
/* We still need to mark the entry we previously prefetched. */
/* We alrady know that it passes the preliminary pointer */
/* validity test. */
- HC_PUSH_CONTENTS((ptr_t)deferred, GC_mark_stack_top_reg,
+ HC_PUSH_CONTENTS((ptr_t)deferred, mark_stack_top,
mark_stack_limit, current_p, exit4);
next_object:;
# endif
}
}
- GC_mark_stack_top = GC_mark_stack_top_reg;
+ return mark_stack_top;
+}
+
+#ifdef PARALLEL_MARK
+
+/* We assume we have an ANSI C Compiler. */
+GC_bool GC_help_wanted = FALSE;
+unsigned GC_helper_count = 0;
+unsigned GC_active_count = 0;
+mse * VOLATILE GC_first_nonempty;
+word GC_mark_no = 0;
+
+#define LOCAL_MARK_STACK_SIZE HBLKSIZE
+ /* Under normal circumstances, this is big enough to guarantee */
+ /* We don't overflow half of it in a single call to */
+ /* GC_mark_from. */
+
+
+/* Steal mark stack entries starting at mse low into mark stack local */
+/* until we either steal mse high, or we have max entries. */
+/* Return a pointer to the top of the local mark stack. */
+/* *next is replaced by a pointer to the next unscanned mark stack */
+/* entry. */
+mse * GC_steal_mark_stack(mse * low, mse * high, mse * local,
+ unsigned max, mse **next)
+{
+ mse *p;
+ mse *top = local - 1;
+ unsigned i = 0;
+
+ GC_ASSERT(high >= low-1 && high - low + 1 <= GC_mark_stack_size);
+ for (p = low; p <= high && i <= max; ++p) {
+ word descr = *(volatile word *) &(p -> mse_descr);
+ if (descr != 0) {
+ *(volatile word *) &(p -> mse_descr) = 0;
+ ++top;
+ top -> mse_descr = descr;
+ top -> mse_start = p -> mse_start;
+ GC_ASSERT( top -> mse_descr & GC_DS_TAGS != GC_DS_LENGTH ||
+ top -> mse_descr < GC_greatest_plausible_heap_addr
+ - GC_least_plausible_heap_addr);
+ /* There is no synchronization here. We assume that at */
+ /* least one thread will see the original descriptor. */
+ /* Otherwise we need a barrier. */
+ /* More than one thread may get this entry, but that's only */
+ /* a minor performance problem. */
+ /* If this is a big object, count it as */
+ /* size/256 + 1 objects. */
+ ++i;
+ if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) i += (descr >> 8);
+ }
+ }
+ *next = p;
+ return top;
+}
+
+/* Copy back a local mark stack. */
+/* low and high are inclusive bounds. */
+void GC_return_mark_stack(mse * low, mse * high)
+{
+ mse * my_top;
+ mse * my_start;
+ size_t stack_size;
+
+ if (high < low) return;
+ stack_size = high - low + 1;
+ GC_acquire_mark_lock();
+ my_top = GC_mark_stack_top;
+ my_start = my_top + 1;
+ if (my_start - GC_mark_stack + stack_size > GC_mark_stack_size) {
+# ifdef CONDPRINT
+ if (GC_print_stats) {
+ GC_printf0("No room to copy back mark stack.");
+ }
+# endif
+ GC_mark_state = MS_INVALID;
+ GC_mark_stack_too_small = TRUE;
+ /* We drop the local mark stack. We'll fix things later. */
+ } else {
+ BCOPY(low, my_start, stack_size * sizeof(mse));
+ GC_ASSERT(GC_mark_stack_top = my_top);
+# if !defined(IA64) && !defined(HP_PA)
+ GC_memory_write_barrier();
+# endif
+ /* On IA64, the volatile write acts as a release barrier. */
+ GC_mark_stack_top = my_top + stack_size;
+ }
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+}
+
+/* Mark from the local mark stack. */
+/* On return, the local mark stack is empty. */
+/* But this may be achieved by copying the */
+/* local mark stack back into the global one. */
+void GC_do_local_mark(mse *local_mark_stack, mse *local_top)
+{
+ unsigned n;
+# define N_LOCAL_ITERS 1
+
+# ifdef GC_ASSERTIONS
+ /* Make sure we don't hold mark lock. */
+ GC_acquire_mark_lock();
+ GC_release_mark_lock();
+# endif
+ for (;;) {
+ for (n = 0; n < N_LOCAL_ITERS; ++n) {
+ local_top = GC_mark_from(local_top, local_mark_stack,
+ local_mark_stack + LOCAL_MARK_STACK_SIZE);
+ if (local_top < local_mark_stack) return;
+ if (local_top - local_mark_stack >= LOCAL_MARK_STACK_SIZE/2) {
+ GC_return_mark_stack(local_mark_stack, local_top);
+ return;
+ }
+ }
+ if (GC_mark_stack_top < GC_first_nonempty &&
+ GC_active_count < GC_helper_count
+ && local_top > local_mark_stack + 1) {
+ /* Try to share the load, since the main stack is empty, */
+ /* and helper threads are waiting for a refill. */
+ /* The entries near the bottom of the stack are likely */
+ /* to require more work. Thus we return those, eventhough */
+ /* it's harder. */
+ mse * p;
+ mse * new_bottom = local_mark_stack
+ + (local_top - local_mark_stack)/2;
+ GC_ASSERT(new_bottom > local_mark_stack
+ && new_bottom < local_top);
+ GC_return_mark_stack(local_mark_stack, new_bottom - 1);
+ memmove(local_mark_stack, new_bottom,
+ (local_top - new_bottom + 1) * sizeof(mse));
+ local_top -= (new_bottom - local_mark_stack);
+ }
+ }
+}
+
+#define ENTRIES_TO_GET 5
+
+long GC_markers = 2; /* Normally changed by thread-library- */
+ /* -specific code. */
+
+/* Mark using the local mark stack until the global mark stack is empty */
+/* and ther are no active workers. Update GC_first_nonempty to reflect */
+/* progress. */
+/* Caller does not hold mark lock. */
+/* Caller has already incremented GC_helper_count. We decrement it, */
+/* and maintain GC_active_count. */
+void GC_mark_local(mse *local_mark_stack, int id)
+{
+ mse * my_first_nonempty;
+
+ GC_acquire_mark_lock();
+ GC_active_count++;
+ my_first_nonempty = GC_first_nonempty;
+ GC_ASSERT(GC_first_nonempty >= GC_mark_stack &&
+ GC_first_nonempty <= GC_mark_stack_top + 1);
+# ifdef PRINTSTATS
+ GC_printf1("Starting mark helper %lu\n", (unsigned long)id);
+# endif
+ GC_release_mark_lock();
+ for (;;) {
+ size_t n_on_stack;
+ size_t n_to_get;
+ mse *next;
+ mse * my_top;
+ mse * local_top;
+ mse * global_first_nonempty = GC_first_nonempty;
+
+ GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
+ my_first_nonempty <= GC_mark_stack_top + 1);
+ GC_ASSERT(global_first_nonempty >= GC_mark_stack &&
+ global_first_nonempty <= GC_mark_stack_top + 1);
+ if (my_first_nonempty < global_first_nonempty) {
+ my_first_nonempty = global_first_nonempty;
+ } else if (global_first_nonempty < my_first_nonempty) {
+ GC_compare_and_exchange((word *)(&GC_first_nonempty),
+ (word) global_first_nonempty,
+ (word) my_first_nonempty);
+ /* If this fails, we just go ahead, without updating */
+ /* GC_first_nonempty. */
+ }
+ /* Perhaps we should also update GC_first_nonempty, if it */
+ /* is less. But that would require using atomic updates. */
+ my_top = GC_mark_stack_top;
+ n_on_stack = my_top - my_first_nonempty + 1;
+ if (0 == n_on_stack) {
+ GC_acquire_mark_lock();
+ my_top = GC_mark_stack_top;
+ n_on_stack = my_top - my_first_nonempty + 1;
+ if (0 == n_on_stack) {
+ GC_active_count--;
+ GC_ASSERT(GC_active_count <= GC_helper_count);
+ /* Other markers may redeposit objects */
+ /* on the stack. */
+ if (0 == GC_active_count) GC_notify_all_marker();
+ while (GC_active_count > 0
+ && GC_first_nonempty > GC_mark_stack_top) {
+ /* We will be notified if either GC_active_count */
+ /* reaches zero, or if more objects are pushed on */
+ /* the global mark stack. */
+ GC_wait_marker();
+ }
+ if (GC_active_count == 0 &&
+ GC_first_nonempty > GC_mark_stack_top) {
+ GC_bool need_to_notify = FALSE;
+ /* The above conditions can't be falsified while we */
+ /* hold the mark lock, since neither */
+ /* GC_active_count nor GC_mark_stack_top can */
+ /* change. GC_first_nonempty can only be */
+ /* incremented asynchronously. Thus we know that */
+ /* both conditions actually held simultaneously. */
+ GC_helper_count--;
+ if (0 == GC_helper_count) need_to_notify = TRUE;
+# ifdef PRINTSTATS
+ GC_printf1(
+ "Finished mark helper %lu\n", (unsigned long)id);
+# endif
+ GC_release_mark_lock();
+ if (need_to_notify) GC_notify_all_marker();
+ return;
+ }
+ /* else there's something on the stack again, or */
+ /* another help may push something. */
+ GC_active_count++;
+ GC_ASSERT(GC_active_count > 0);
+ GC_release_mark_lock();
+ continue;
+ } else {
+ GC_release_mark_lock();
+ }
+ }
+ n_to_get = ENTRIES_TO_GET;
+ if (n_on_stack < 2 * ENTRIES_TO_GET) n_to_get = 1;
+ local_top = GC_steal_mark_stack(my_first_nonempty, my_top,
+ local_mark_stack, n_to_get,
+ &my_first_nonempty);
+ GC_ASSERT(my_first_nonempty >= GC_mark_stack &&
+ my_first_nonempty <= GC_mark_stack_top + 1);
+ GC_do_local_mark(local_mark_stack, local_top);
+ }
}
+/* Perform Parallel mark. */
+/* We hold the GC lock, not the mark lock. */
+/* Currently runs until the mark stack is */
+/* empty. */
+void GC_do_parallel_mark()
+{
+ mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
+ mse * local_top;
+ mse * my_top;
+
+ GC_acquire_mark_lock();
+ GC_ASSERT(I_HOLD_LOCK());
+ GC_ASSERT(!GC_help_wanted);
+ GC_ASSERT(GC_active_count == 0);
+# ifdef PRINTSTATS
+ GC_printf1("Starting marking for mark phase number %lu\n",
+ (unsigned long)GC_mark_no);
+# endif
+ GC_first_nonempty = GC_mark_stack;
+ GC_active_count = 0;
+ GC_helper_count = 1;
+ GC_help_wanted = TRUE;
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+ /* Wake up potential helpers. */
+ GC_mark_local(local_mark_stack, 0);
+ GC_acquire_mark_lock();
+ GC_help_wanted = FALSE;
+ /* Done; clean up. */
+ while (GC_helper_count > 0) GC_wait_marker();
+ /* GC_helper_count cannot be incremented while GC_help_wanted == FALSE */
+# ifdef PRINTSTATS
+ GC_printf1(
+ "Finished marking for mark phase number %lu\n",
+ (unsigned long)GC_mark_no);
+# endif
+ GC_mark_no++;
+ GC_release_mark_lock();
+ GC_notify_all_marker();
+}
+
+
+/* Try to help out the marker, if it's running. */
+/* We do not hold the GC lock, but the requestor does. */
+void GC_help_marker(word my_mark_no)
+{
+ mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
+ unsigned my_id;
+ mse * my_first_nonempty;
+
+ if (!GC_parallel) return;
+ GC_acquire_mark_lock();
+ while (GC_mark_no < my_mark_no
+ || !GC_help_wanted && GC_mark_no == my_mark_no) {
+ GC_wait_marker();
+ }
+ my_id = GC_helper_count;
+ if (GC_mark_no != my_mark_no || my_id >= GC_markers) {
+ /* Second test is useful only if original threads can also */
+ /* act as helpers. Under Linux they can't. */
+ GC_release_mark_lock();
+ return;
+ }
+ GC_helper_count = my_id + 1;
+ GC_release_mark_lock();
+ GC_mark_local(local_mark_stack, my_id);
+ /* GC_mark_local decrements GC_helper_count. */
+}
+
+#endif /* PARALLEL_MARK */
+
/* Allocate or reallocate space for mark stack of size s words */
/* May silently fail. */
static void alloc_mark_stack(n)
word n;
{
- mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct ms_entry));
+ mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct GC_ms_entry));
GC_mark_stack_too_small = FALSE;
if (GC_mark_stack_size != 0) {
if (new_stack != 0) {
word displ = (word)GC_mark_stack & (GC_page_size - 1);
- signed_word size = GC_mark_stack_size * sizeof(struct ms_entry);
+ signed_word size = GC_mark_stack_size * sizeof(struct GC_ms_entry);
/* Recycle old space */
if (0 != displ) displ = GC_page_size - displ;
@@ -655,14 +1031,19 @@ word n;
}
GC_mark_stack = new_stack;
GC_mark_stack_size = n;
-# ifdef PRINTSTATS
+ GC_mark_stack_limit = new_stack + n;
+# ifdef CONDPRINT
+ if (GC_print_stats) {
GC_printf1("Grew mark stack to %lu frames\n",
(unsigned long) GC_mark_stack_size);
+ }
# endif
} else {
-# ifdef PRINTSTATS
+# ifdef CONDPRINT
+ if (GC_print_stats) {
GC_printf1("Failed to grow mark stack to %lu frames\n",
(unsigned long) n);
+ }
# endif
}
} else {
@@ -672,6 +1053,7 @@ word n;
}
GC_mark_stack = new_stack;
GC_mark_stack_size = n;
+ GC_mark_stack_limit = new_stack + n;
}
GC_mark_stack_top = GC_mark_stack-1;
}
@@ -698,32 +1080,33 @@ ptr_t top;
top = (ptr_t)(((word) top) & ~(ALIGNMENT-1));
if (top == 0 || bottom == top) return;
GC_mark_stack_top++;
- if (GC_mark_stack_top >= GC_mark_stack + GC_mark_stack_size) {
+ if (GC_mark_stack_top >= GC_mark_stack_limit) {
ABORT("unexpected mark stack overflow");
}
length = top - bottom;
-# if DS_TAGS > ALIGNMENT - 1
- length += DS_TAGS;
- length &= ~DS_TAGS;
+# if GC_DS_TAGS > ALIGNMENT - 1
+ length += GC_DS_TAGS;
+ length &= ~GC_DS_TAGS;
# endif
GC_mark_stack_top -> mse_start = (word *)bottom;
GC_mark_stack_top -> mse_descr = length;
}
/*
- * Analogous to the above, but push only those pages that may have been
- * dirtied. A block h is assumed dirty if dirty_fn(h) != 0.
+ * Analogous to the above, but push only those pages h with dirty_fn(h) != 0.
* We use push_fn to actually push the block.
+ * Used both to selectively push dirty pages, or to push a block
+ * in piecemeal fashion, to allow for more marking concurrency.
* Will not overflow mark stack if push_fn pushes a small fixed number
* of entries. (This is invoked only if push_fn pushes a single entry,
* or if it marks each object before pushing it, thus ensuring progress
* in the event of a stack overflow.)
*/
-void GC_push_dirty(bottom, top, dirty_fn, push_fn)
+void GC_push_selected(bottom, top, dirty_fn, push_fn)
ptr_t bottom;
ptr_t top;
-int (*dirty_fn)(/* struct hblk * h */);
-void (*push_fn)(/* ptr_t bottom, ptr_t top */);
+int (*dirty_fn) GC_PROTO((struct hblk * h));
+void (*push_fn) GC_PROTO((ptr_t bottom, ptr_t top));
{
register struct hblk * h;
@@ -759,12 +1142,23 @@ void (*push_fn)(/* ptr_t bottom, ptr_t top */);
(*push_fn)((ptr_t)h, top);
}
}
- if (GC_mark_stack_top >= GC_mark_stack + GC_mark_stack_size) {
+ if (GC_mark_stack_top >= GC_mark_stack_limit) {
ABORT("unexpected mark stack overflow");
}
}
# ifndef SMALL_CONFIG
+
+#ifdef PARALLEL_MARK
+ /* Break up root sections into page size chunks to better spread */
+ /* out work. */
+ GC_bool GC_true_func(struct hblk *h) { return TRUE; }
+# define GC_PUSH_ALL(b,t) GC_push_selected(b,t,GC_true_func,GC_push_all);
+#else
+# define GC_PUSH_ALL(b,t) GC_push_all(b,t);
+#endif
+
+
void GC_push_conditional(bottom, top, all)
ptr_t bottom;
ptr_t top;
@@ -774,7 +1168,7 @@ int all;
if (GC_dirty_maintained) {
# ifdef PROC_VDB
/* Pages that were never dirtied cannot contain pointers */
- GC_push_dirty(bottom, top, GC_page_was_ever_dirty, GC_push_all);
+ GC_push_selected(bottom, top, GC_page_was_ever_dirty, GC_push_all);
# else
GC_push_all(bottom, top);
# endif
@@ -782,43 +1176,54 @@ int all;
GC_push_all(bottom, top);
}
} else {
- GC_push_dirty(bottom, top, GC_page_was_dirty, GC_push_all);
+ GC_push_selected(bottom, top, GC_page_was_dirty, GC_push_all);
}
}
#endif
-# ifdef MSWIN32
+# if defined(MSWIN32) || defined(MSWINCE)
void __cdecl GC_push_one(p)
# else
void GC_push_one(p)
# endif
word p;
{
-# ifdef NURSERY
- if (0 != GC_push_proc) {
- GC_push_proc(p);
- return;
- }
-# endif
GC_PUSH_ONE_STACK(p, MARKED_FROM_REGISTER);
}
+struct GC_ms_entry *GC_mark_and_push(obj, mark_stack_ptr, mark_stack_limit, src)
+GC_PTR obj;
+struct GC_ms_entry * mark_stack_ptr;
+struct GC_ms_entry * mark_stack_limit;
+GC_PTR *src;
+{
+ PREFETCH(obj);
+ PUSH_CONTENTS(obj, mark_stack_ptr /* modified */, mark_stack_limit, src,
+ was_marked /* internally generated exit label */);
+ return mark_stack_ptr;
+}
+
# ifdef __STDC__
# define BASE(p) (word)GC_base((void *)(p))
# else
# define BASE(p) (word)GC_base((char *)(p))
# endif
-/* As above, but argument passed preliminary test. */
+/* Mark and push (i.e. gray) a single object p onto the main */
+/* mark stack. Consider p to be valid if it is an interior */
+/* pointer. */
+/* The object p has passed a preliminary pointer validity */
+/* test, but we do not definitely know whether it is valid. */
+/* Mark bits are NOT atomically updated. Thus this must be the */
+/* only thread setting them. */
# if defined(PRINT_BLACK_LIST) || defined(KEEP_BACK_PTRS)
- void GC_push_one_checked(p, interior_ptrs, source)
+ void GC_mark_and_push_stack(p, source)
ptr_t source;
# else
- void GC_push_one_checked(p, interior_ptrs)
+ void GC_mark_and_push_stack(p)
# define source 0
# endif
register word p;
-register GC_bool interior_ptrs;
{
register word r;
register hdr * hhdr;
@@ -826,31 +1231,25 @@ register GC_bool interior_ptrs;
GET_HDR(p, hhdr);
if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
- if (hhdr != 0 && interior_ptrs) {
+ if (hhdr != 0) {
r = BASE(p);
hhdr = HDR(r);
displ = BYTES_TO_WORDS(HBLKDISPL(r));
- } else {
- hhdr = 0;
}
} else {
register map_entry_type map_entry;
displ = HBLKDISPL(p);
map_entry = MAP_ENTRY((hhdr -> hb_map), displ);
- if (map_entry == OBJ_INVALID) {
-# ifndef ALL_INTERIOR_POINTERS
- if (interior_ptrs) {
+ if (map_entry >= MAX_OFFSET) {
+ if (map_entry == OFFSET_TOO_BIG || !GC_all_interior_pointers) {
r = BASE(p);
displ = BYTES_TO_WORDS(HBLKDISPL(r));
if (r == 0) hhdr = 0;
- } else {
+ } else {
+ /* Offset invalid, but map reflects interior pointers */
hhdr = 0;
- }
-# else
- /* map already reflects interior pointers */
- hhdr = 0;
-# endif
+ }
} else {
displ = BYTES_TO_WORDS(displ);
displ -= map_entry;
@@ -860,22 +1259,18 @@ register GC_bool interior_ptrs;
/* If hhdr != 0 then r == GC_base(p), only we did it faster. */
/* displ is the word index within the block. */
if (hhdr == 0) {
- if (interior_ptrs) {
-# ifdef PRINT_BLACK_LIST
- GC_add_to_black_list_stack(p, source);
-# else
- GC_add_to_black_list_stack(p);
-# endif
- } else {
- GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
-# undef source /* In case we had to define it. */
- }
+# ifdef PRINT_BLACK_LIST
+ GC_add_to_black_list_stack(p, source);
+# else
+ GC_add_to_black_list_stack(p);
+# endif
+# undef source /* In case we had to define it. */
} else {
if (!mark_bit_from_hdr(hhdr, displ)) {
set_mark_bit_from_hdr(hhdr, displ);
GC_STORE_BACK_PTR(source, (ptr_t)r);
PUSH_OBJ((word *)r, hhdr, GC_mark_stack_top,
- &(GC_mark_stack[GC_mark_stack_size]));
+ GC_mark_stack_limit);
}
}
}
@@ -969,7 +1364,7 @@ ptr_t bottom;
ptr_t top;
ptr_t cold_gc_frame;
{
-# ifdef ALL_INTERIOR_POINTERS
+ if (GC_all_interior_pointers) {
# define EAGER_BYTES 1024
/* Push the hot end of the stack eagerly, so that register values */
/* saved inside GC frames are marked before they disappear. */
@@ -985,9 +1380,9 @@ ptr_t cold_gc_frame;
GC_push_all_eager(cold_gc_frame, top);
GC_push_all(bottom, cold_gc_frame + sizeof(ptr_t));
# endif /* STACK_GROWS_UP */
-# else
+ } else {
GC_push_all_eager(bottom, top);
-# endif
+ }
# ifdef TRACE_BUF
GC_add_trace_entry("GC_push_all_stack", bottom, top);
# endif
@@ -998,21 +1393,21 @@ void GC_push_all_stack(bottom, top)
ptr_t bottom;
ptr_t top;
{
-# ifdef ALL_INTERIOR_POINTERS
+ if (GC_all_interior_pointers) {
GC_push_all(bottom, top);
-# else
+ } else {
GC_push_all_eager(bottom, top);
-# endif
+ }
}
-#ifndef SMALL_CONFIG
+#if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
/* Push all objects reachable from marked objects in the given block */
/* of size 1 objects. */
void GC_push_marked1(h, hhdr)
struct hblk *h;
register hdr * hhdr;
{
- word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p;
word *plim;
register int i;
@@ -1020,6 +1415,10 @@ register hdr * hhdr;
register word mark_word;
register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
register ptr_t least_ha = GC_least_plausible_heap_addr;
+ register mse * mark_stack_top = GC_mark_stack_top;
+ register mse * mark_stack_limit = GC_mark_stack_limit;
+# define GC_mark_stack_top mark_stack_top
+# define GC_mark_stack_limit mark_stack_limit
# define GC_greatest_plausible_heap_addr greatest_ha
# define GC_least_plausible_heap_addr least_ha
@@ -1042,6 +1441,9 @@ register hdr * hhdr;
}
# undef GC_greatest_plausible_heap_addr
# undef GC_least_plausible_heap_addr
+# undef GC_mark_stack_top
+# undef GC_mark_stack_limit
+ GC_mark_stack_top = mark_stack_top;
}
@@ -1053,7 +1455,7 @@ void GC_push_marked2(h, hhdr)
struct hblk *h;
register hdr * hhdr;
{
- word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p;
word *plim;
register int i;
@@ -1061,6 +1463,10 @@ register hdr * hhdr;
register word mark_word;
register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
register ptr_t least_ha = GC_least_plausible_heap_addr;
+ register mse * mark_stack_top = GC_mark_stack_top;
+ register mse * mark_stack_limit = GC_mark_stack_limit;
+# define GC_mark_stack_top mark_stack_top
+# define GC_mark_stack_limit mark_stack_limit
# define GC_greatest_plausible_heap_addr greatest_ha
# define GC_least_plausible_heap_addr least_ha
@@ -1085,6 +1491,9 @@ register hdr * hhdr;
}
# undef GC_greatest_plausible_heap_addr
# undef GC_least_plausible_heap_addr
+# undef GC_mark_stack_top
+# undef GC_mark_stack_limit
+ GC_mark_stack_top = mark_stack_top;
}
/* Push all objects reachable from marked objects in the given block */
@@ -1095,7 +1504,7 @@ void GC_push_marked4(h, hhdr)
struct hblk *h;
register hdr * hhdr;
{
- word * mark_word_addr = &(hhdr->hb_marks[divWORDSZ(HDR_WORDS)]);
+ word * mark_word_addr = &(hhdr->hb_marks[0]);
register word *p;
word *plim;
register int i;
@@ -1103,6 +1512,10 @@ register hdr * hhdr;
register word mark_word;
register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
register ptr_t least_ha = GC_least_plausible_heap_addr;
+ register mse * mark_stack_top = GC_mark_stack_top;
+ register mse * mark_stack_limit = GC_mark_stack_limit;
+# define GC_mark_stack_top mark_stack_top
+# define GC_mark_stack_limit mark_stack_limit
# define GC_greatest_plausible_heap_addr greatest_ha
# define GC_least_plausible_heap_addr least_ha
@@ -1131,6 +1544,9 @@ register hdr * hhdr;
}
# undef GC_greatest_plausible_heap_addr
# undef GC_least_plausible_heap_addr
+# undef GC_mark_stack_top
+# undef GC_mark_stack_limit
+ GC_mark_stack_top = mark_stack_top;
}
#endif /* UNALIGNED */
@@ -1148,28 +1564,27 @@ register hdr * hhdr;
register int word_no;
register word * lim;
register mse * GC_mark_stack_top_reg;
- register mse * mark_stack_limit = &(GC_mark_stack[GC_mark_stack_size]);
+ register mse * mark_stack_limit = GC_mark_stack_limit;
/* Some quick shortcuts: */
- if ((0 | DS_LENGTH) == descr) return;
+ if ((0 | GC_DS_LENGTH) == descr) return;
if (GC_block_empty(hhdr)/* nothing marked */) return;
-# ifdef GATHERSTATS
- GC_n_rescuing_pages++;
-# endif
+ GC_n_rescuing_pages++;
GC_objects_are_marked = TRUE;
if (sz > MAXOBJSZ) {
- lim = (word *)h + HDR_WORDS;
+ lim = (word *)h;
} else {
lim = (word *)(h + 1) - sz;
}
switch(sz) {
-# if !defined(SMALL_CONFIG)
+# if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
case 1:
GC_push_marked1(h, hhdr);
break;
# endif
-# if !defined(SMALL_CONFIG) && !defined(UNALIGNED)
+# if !defined(SMALL_CONFIG) && !defined(UNALIGNED) && \
+ !defined(USE_MARK_BYTES)
case 2:
GC_push_marked2(h, hhdr);
break;
@@ -1179,8 +1594,7 @@ register hdr * hhdr;
# endif
default:
GC_mark_stack_top_reg = GC_mark_stack_top;
- for (p = (word *)h + HDR_WORDS, word_no = HDR_WORDS; p <= lim;
- p += sz, word_no += sz) {
+ for (p = (word *)h, word_no = 0; p <= lim; p += sz, word_no += sz) {
if (mark_bit_from_hdr(hhdr, word_no)) {
/* Mark from fields inside the object */
PUSH_OBJ((word *)p, hhdr, GC_mark_stack_top_reg, mark_stack_limit);
@@ -1207,7 +1621,6 @@ register hdr * hhdr;
return(GC_page_was_dirty(h));
} else {
register ptr_t p = (ptr_t)h;
- sz += HDR_WORDS;
sz = WORDS_TO_BYTES(sz);
while (p < (ptr_t)h + sz) {
if (GC_page_was_dirty((struct hblk *)p)) return(TRUE);