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Fixing bug due to arena table pages being marked as allocated

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 Change: 18200
 ServerID: perforce.ravenbrook.com
This commit is contained in:
David Jones 1997-05-22 16:38:52 +01:00
parent ee42c19570
commit e86be2dcf9
1 changed files with 25 additions and 16 deletions
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41
mps/src/arenavm.c
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@ -1,6 +1,6 @@
/* impl.c.arenavm: VIRTUAL MEMORY BASED ARENA IMPLEMENTATION
*
* $HopeName: MMsrc!arenavm.c(trunk.15) $
* $HopeName: MMsrc!arenavm.c(trunk.16) $
* Copyright (C) 1997 The Harlequin Group Limited. All rights reserved.
*
* This is the implementation of the Segment abstraction from the VM
@ -14,7 +14,7 @@
#include "mpm.h"
SRCID(arenavm, "$HopeName: MMsrc!arenavm.c(trunk.15) $");
SRCID(arenavm, "$HopeName: MMsrc!arenavm.c(trunk.16) $");
/* Space Arena Projection
@ -93,8 +93,8 @@ Res ArenaCreate(Space *spaceReturn, Size size, Addr base)
*
* .improve.table.zone-zero: It would be better to make sure that the
* page tables are in zone zero, since that zone is least useful for
* GC. (but it would change how SegAlloc avoids allocating over the
* tables, see .alloc.skip)
* GC. (but it would change how SegAllocWithRefSet avoids allocating
* over the tables, see .alloc.skip)
*
* There are two tables, the free table which is a bool array, and the
* page table which is a PageStruct array. Both tables are allocated
@ -120,11 +120,12 @@ Res ArenaCreate(Space *spaceReturn, Size size, Addr base)
/* .tablepages: pages whose page index is < tablePages are recorded as
* free but never allocated as alloc starts searching after the tables
* (see .alloc.skip)
* (see .alloc.skip). SegOfAddr uses the fact that these pages are
* marked as free in order to detect "references" to these pages as
* being bogus see .addr.free.
*/
arena->tablePages = arena->tablesSize >> arena->pageShift;
BTResRange(arena->freeTable, 0, arena->tablePages);
BTSetRange(arena->freeTable, arena->tablePages, arena->pages);
BTSetRange(arena->freeTable, 0, arena->pages);
/* Set the zone shift to divide the arena into the same number of
* zones as will fit into a reference set (the number of bits in a
@ -277,7 +278,7 @@ static Index IndexOfAddr(Arena arena, Addr addr)
}
/* SegAllocWithRefSet -- try to allocate a segment in an area
/* SegAllocInArea -- try to allocate a segment in an area
*
* Search for a free run of pages in the free table, but between
* base and limit.
@ -286,7 +287,8 @@ static Index IndexOfAddr(Arena arena, Addr addr)
* optimised by twiddling the bit table.
*/
static Bool SegAllocInArea(Index *baseReturn, Space space, Size size, Addr base, Addr limit)
static Bool SegAllocInArea(Index *baseReturn,
Space space, Size size, Addr base, Addr limit)
{
Arena arena;
Word pages; /* number of pages equiv. to size */
@ -328,20 +330,23 @@ static Bool SegAllocInArea(Index *baseReturn, Space space, Size size, Addr base,
}
/* SegAllocWithRefSet -- try to allocate a segment with a particular RefSet
*
* This function finds the intersection of refSet and the set of free pages
* and tries to allocate a segment in the resulting set of areas.
/* SegAllocWithRefSet
* -- try to allocate a segment with a particular RefSet
*
* This function finds the intersection of refSet and the set of free
* pages and tries to allocate a segment in the resulting set of
* areas.
*/
static Bool SegAllocWithRefSet(Index *baseReturn, Space space, Size size, RefSet refSet)
static Bool SegAllocWithRefSet(Index *baseReturn,
Space space, Size size, RefSet refSet)
{
Arena arena = SpaceArena(space);
Addr arenaBase, base, limit;
Size zoneSize = (Size)1 << space->zoneShift;
/* This is the first address available for segments, just after the */
/* arena tables. */
/* .alloc.skip: The first address available for segments, */
/* is just after the arena tables. */
arenaBase = PageBase(arena, arena->tablePages);
base = arenaBase;
@ -601,8 +606,12 @@ Bool SegOfAddr(Seg *segReturn, Space space, Addr addr)
arena = SpaceArena(space);
if(arena->base <= addr && addr < arena->limit) {
Index i = IndexOfAddr(arena, addr);
/* .addr.free: If the page is recorded as being free then */
/* either the page is free or it is */
/* part of the arena tables (see .tablepages) */
if(!BTGet(arena->freeTable, i)) {
Page page = &arena->pageTable[i];
if(page->the.head.pool != NULL)
*segReturn = &page->the.head;
else