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Add MptrEndBags
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This allows for a seperation between the end of the master
pointers, and the beginning of the bag data area
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@ChrisJefferson @fingolfin
ChrisJefferson authored and fingolfin committed Mar 28, 2018
1 parent 5ddf61c commit 71b6290
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Showing 4 changed files with 45 additions and 31 deletions.
2 changes: 1 addition & 1 deletion src/gap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1985,7 +1985,7 @@ Obj FuncMASTER_POINTER_NUMBER(Obj self, Obj o)
return INTOBJ_INT(0);
}
#ifdef USE_GASMAN
if ((void **) o >= (void **) MptrBags && (void **) o < (void **) OldBags) {
if ((void **) o >= (void **) MptrBags && (void **) o < (void **) MptrEndBags) {
return INTOBJ_INT( ((void **) o - (void **) MptrBags) + 1 );
} else {
return INTOBJ_INT( 0 );
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64 changes: 39 additions & 25 deletions src/gasman.c
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Original file line number Diff line number Diff line change
Expand Up @@ -211,6 +211,7 @@ static inline Bag *DATA(BagHeader *bag)
/****************************************************************************
**
*V MptrBags . . . . . . . . . . . . . . beginning of the masterpointer area
*V MptrEndBags . . . . . . . . . . . . . . . end of the masterpointer area
*V OldBags . . . . . . . . . . . . . . . . . beginning of the old bags area
*V YoungBags . . . . . . . . . . . . . . . beginning of the young bags area
*V AllocBags . . . . . . . . . . . . . . . beginning of the allocation area
Expand All @@ -220,15 +221,21 @@ static inline Bag *DATA(BagHeader *bag)
** {\Gasman} manages one large block of storage called the *workspace*. The
** layout of the workspace is as follows{\:}
**
** +-----------------+-----------------+-----------------+-----------------+
** | masterpointer | old bags | young bags | allocation |
** | area | area | area | area |
** +-----------------+-----------------+-----------------+-----------------+
** ^ ^ ^ ^ ^
** MptrBags OldBags YoungBags AllocBags EndBags
** +----------------+----------+----------+-----------------+--------------+
** | masterpointer | unused | old bags | young bags | allocation |
** | area | area | area | area | area |
** +----------------+----------+----------+-----------------+--------------+
** ^ ^ ^ ^ ^ ^
** MptrBags MptrEndBags OldBags YoungBags AllocBags EndBags
**
** The *masterpointer area* contains all the masterpointers of the bags.
** 'MptrBags' points to the beginning of this area and 'OldBags' to the end.
** 'MptrBags' points to the beginning of this area and 'MptrEndBags' to the
** end.
**
** Between MptrEndBags and OldBags is an *unused area*. This exists so the
** master points, and bags area, can be moved independently. MptrEndBags
** will always come earlier in memory than OldBags. GASMAN should not touch
** this memory, as it may be used for other purposes.
**
** The *old bags area* contains the bodies of all the bags that survived at
** least one garbage collection. This area is only scanned for dead bags
Expand All @@ -253,6 +260,7 @@ static inline Bag *DATA(BagHeader *bag)
** empties the young bags area.
*/
Bag * MptrBags;
Bag * MptrEndBags;
Bag * OldBags;
Bag * YoungBags;
Bag * AllocBags;
Expand Down Expand Up @@ -307,7 +315,7 @@ static inline UInt SpaceBetweenPointers(const Bag * a, const Bag * b)
return res;
}

#define SizeMptrsArea SpaceBetweenPointers(OldBags, MptrBags)
#define SizeMptrsArea SpaceBetweenPointers(MptrEndBags, MptrBags)
#define SizeOldBagsArea SpaceBetweenPointers(YoungBags, OldBags)
#define SizeYoungBagsArea SpaceBetweenPointers(AllocBags, YoungBags)
#define SizeAllocationArea SpaceBetweenPointers(EndBags, AllocBags)
Expand All @@ -318,7 +326,8 @@ static inline UInt SpaceBetweenPointers(const Bag * a, const Bag * b)
#if defined(GAP_KERNEL_DEBUG)
static int SanityCheckGasmanPointers(void)
{
return MptrBags <= OldBags &&
return MptrBags <= MptrEndBags &&
MptrEndBags <= OldBags &&
OldBags <= YoungBags &&
YoungBags <= AllocBags &&
AllocBags <= EndBags;
Expand Down Expand Up @@ -457,7 +466,7 @@ TNumInfoBags InfoBags [ NTYPES ];
*/
static inline UInt IS_BAG_ID(void * ptr)
{
return (((void *)MptrBags <= ptr) && (ptr < (void *)OldBags) &&
return (((void *)MptrBags <= ptr) && (ptr < (void *)MptrEndBags) &&
((UInt)ptr & (sizeof(Bag) - 1)) == 0);
}

Expand Down Expand Up @@ -687,7 +696,7 @@ void MarkBagWeakly(Bag bag)
*/
void CallbackForAllBags(void (*func)(Bag))
{
for (Bag bag = (Bag)MptrBags; bag < (Bag)OldBags; bag++) {
for (Bag bag = (Bag)MptrBags; bag < (Bag)MptrEndBags; bag++) {
if (IS_BAG_BODY(*bag)) {
(*func)(bag);
}
Expand Down Expand Up @@ -872,6 +881,7 @@ void StartRestoringBags( UInt nBags, UInt maxSize)
EndBags = MptrBags + target;
}
OldBags = MptrBags + nBags + (SizeWorkspace - nBags - maxSize)/8;
MptrEndBags = OldBags;
AllocBags = OldBags;
NextMptrRestoring = (Bag)MptrBags;
SizeAllBags = 0;
Expand All @@ -891,7 +901,7 @@ Bag NextBagRestoring( UInt type, UInt flags, UInt size )
header->link = NextMptrRestoring;
NextMptrRestoring++;

if ((Bag *)NextMptrRestoring >= OldBags)
if ((Bag *)NextMptrRestoring >= MptrEndBags)
SyAbortBags("Overran Masterpointer area");

for (i = 0; i < WORDS_BAG(size); i++)
Expand All @@ -917,7 +927,7 @@ void FinishedRestoringBags( void )
/* Bag *ptr; */
YoungBags = AllocBags;
FreeMptrBags = NextMptrRestoring;
for (p = NextMptrRestoring; p +1 < (Bag)OldBags; p++)
for (p = NextMptrRestoring; p +1 < (Bag)MptrEndBags; p++)
*(Bag *)p = p+1;
*p = 0;
NrLiveBags = NrAllBags;
Expand Down Expand Up @@ -1032,7 +1042,11 @@ void InitBags (
}

/* the rest is for bags */
OldBags = MptrBags + 1024*initial_size/8/sizeof(Bag*);
MptrEndBags = MptrBags + 1024*initial_size/8/sizeof(Bag*);
// Add a small gap between the end of the master pointers and OldBags
// This is mainly here to ensure we do not break allowing OldBags and
// MptrEndBags to differ.
OldBags = MptrEndBags + 10;
YoungBags = OldBags;
AllocBags = OldBags;

Expand Down Expand Up @@ -2007,7 +2021,7 @@ UInt CollectBags (
also reorder the free masterpointer linked list
to get more locality */
FreeMptrBags = (Bag)0L;
for (p = MptrBags; p < OldBags; p+= SIZE_MPTR_BAGS)
for (p = MptrBags; p < MptrEndBags; p+= SIZE_MPTR_BAGS)
{
Bag *mptr = (Bag *)*p;
if ( mptr == OldWeakDeadBagMarker)
Expand Down Expand Up @@ -2039,13 +2053,13 @@ UInt CollectBags (
AllocSizeBags = 7*(Endbags - stopBags)/8; */

/* if less than 1/16th is free, prepare for an interrupt */
if (SpaceBetweenPointers(stopBags,OldBags)/15 < SpaceBetweenPointers(EndBags,stopBags) ) {
if (SpaceBetweenPointers(stopBags,MptrEndBags)/15 < SpaceBetweenPointers(EndBags,stopBags) ) {
/*N 1993/05/16 martin must change 'gap.c' */
;
}

/* if more than 1/8th is free, give back storage (in 1/2 MBytes) */
while (SpaceBetweenPointers(stopBags,OldBags)/7 <= SpaceBetweenPointers(EndBags,stopBags)-WORDS_BAG(512*1024L)
while (SpaceBetweenPointers(stopBags,MptrEndBags)/7 <= SpaceBetweenPointers(EndBags,stopBags)-WORDS_BAG(512*1024L)
&& SpaceBetweenPointers(EndBags,stopBags) > WORDS_BAG(AllocSizeBags) + WORDS_BAG(512*1024L)
&& SyAllocBags(-512,0) )
EndBags -= WORDS_BAG(512*1024L);
Expand All @@ -2060,26 +2074,26 @@ UInt CollectBags (
SyMemmove(OldBags+i, OldBags, SizeAllBagsArea*sizeof(*OldBags));

/* update the masterpointers */
for ( p = MptrBags; p < OldBags; p++ ) {
if ( (Bag)OldBags <= *p)
for ( p = MptrBags; p < MptrEndBags; p++ ) {
if ( (Bag)MptrEndBags <= *p)
*p += i;
}

/* link the new part of the masterpointer area */
for ( p = OldBags;
p + 2*SIZE_MPTR_BAGS <= OldBags+i;
for ( p = MptrEndBags;
p + 2*SIZE_MPTR_BAGS <= MptrEndBags+i;
p += SIZE_MPTR_BAGS ) {
*p = (Bag)(p + SIZE_MPTR_BAGS);
}
*p = (Bag)FreeMptrBags;
FreeMptrBags = (Bag)OldBags;
FreeMptrBags = (Bag)MptrEndBags;

/* update 'OldBags', 'YoungBags', 'AllocBags', and 'stopBags' */
/* update 'MptrEndBags', 'OldBags', 'YoungBags', 'AllocBags', and 'stopBags' */
MptrEndBags += i;
OldBags += i;
YoungBags += i;
AllocBags += i;
stopBags += i;

}

/* now we are done */
Expand Down Expand Up @@ -2132,7 +2146,7 @@ void CheckMasterPointers( void )
Bag bag;

// iterate over all bag identifiers
for (Bag * ptr = MptrBags; ptr < OldBags; ptr++) {
for (Bag * ptr = MptrBags; ptr < MptrEndBags; ptr++) {
bag = (Bag)ptr;

// weakly dead bag?
Expand Down
4 changes: 2 additions & 2 deletions src/gasman.h
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Original file line number Diff line number Diff line change
Expand Up @@ -877,12 +877,12 @@ extern void MarkArrayOfBags(const Bag array[], UInt count);
#ifdef USE_GASMAN

extern Bag * MptrBags;
extern Bag * OldBags;
extern Bag * MptrEndBags;
extern Bag * AllocBags;

#define IS_WEAK_DEAD_BAG(bag) ( (((UInt)bag & (sizeof(Bag)-1)) == 0) && \
(Bag)MptrBags <= (bag) && \
(bag) < (Bag)OldBags && \
(bag) < (Bag)MptrEndBags && \
(((UInt)*bag) & (sizeof(Bag)-1)) == 1)

#elif defined(USE_BOEHM_GC)
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6 changes: 3 additions & 3 deletions src/saveload.c
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Original file line number Diff line number Diff line change
Expand Up @@ -314,8 +314,8 @@ void SaveSubObj( Obj subobj )
SaveUInt((UInt) subobj);
else if ((((UInt)subobj & 3) != 0) ||
subobj < (Bag)MptrBags ||
subobj > (Bag)OldBags ||
(Bag *)PTR_BAG(subobj) < OldBags)
subobj > (Bag)MptrEndBags ||
(Bag *)PTR_BAG(subobj) < MptrEndBags)
{
Pr("#W bad bag id %d found, 0 saved\n", (Int)subobj, 0L);
SaveUInt(0);
Expand Down Expand Up @@ -553,7 +553,7 @@ static void WriteSaveHeader( void )
globalcount++;
SaveUInt(globalcount);
SaveUInt(NextSaveIndex-1);
SaveUInt(AllocBags - OldBags);
SaveUInt(AllocBags - MptrEndBags);

SaveCStr("Loaded Modules");

Expand Down

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