/* MVFFAddSeg -- Allocates a new segment from the arena
*
* Allocates a new segment from the arena (with the given
* withReservoirPermit flag) of at least the specified size. The
* specified size should be pool-aligned. Adds it to the free list.
*/
static Res MVFFAddSeg(Seg *segReturn,
MVFF mvff, Size size, Bool withReservoirPermit)
{
Pool pool;
Arena arena;
Size segSize;
Seg seg;
Res res;
Align align;
Addr base, limit;
AVERT(MVFF, mvff);
AVER(size > 0);
AVERT(Bool, withReservoirPermit);
pool = MVFF2Pool(mvff);
arena = PoolArena(pool);
align = ArenaAlign(arena);
AVER(SizeIsAligned(size, PoolAlignment(pool)));
/* Use extendBy unless it's too small (see */
/* <design/poolmvff/#design.seg-size>). */
if (size <= mvff->extendBy)
segSize = mvff->extendBy;
else
segSize = size;
segSize = SizeAlignUp(segSize, align);
res = SegAlloc(&seg, SegClassGet(), mvff->segPref, segSize, pool,
withReservoirPermit, argsNone);
if (res != ResOK) {
/* try again for a seg just large enough for object */
/* see <design/poolmvff/#design.seg-fail> */
segSize = SizeAlignUp(size, align);
res = SegAlloc(&seg, SegClassGet(), mvff->segPref, segSize, pool,
withReservoirPermit, argsNone);
if (res != ResOK) {
return res;
}
}
mvff->total += segSize;
base = SegBase(seg);
limit = AddrAdd(base, segSize);
DebugPoolFreeSplat(pool, base, limit);
res = MVFFAddToFreeList(&base, &limit, mvff);
AVER(res == ResOK);
AVER(base <= SegBase(seg));
if (mvff->minSegSize > segSize) mvff->minSegSize = segSize;
/* Don't call MVFFFreeSegs; that would be silly. */
*segReturn = seg;
return ResOK;
}
/* MVFFFreeSegs -- Free segments from given range
*
* Given a free range, attempts to find entire segments within
* it, and returns them to the arena, updating total size counter.
*
* This is usually called immediately after MVFFAddToFreeList.
* It is not combined with MVFFAddToFreeList because the latter
* is also called when new segments are added under MVFFAlloc.
*/
static void MVFFFreeSegs(MVFF mvff, Addr base, Addr limit)
{
Seg seg = NULL; /* suppress "may be used uninitialized" */
Arena arena;
Bool b;
Addr segLimit; /* limit of the current segment when iterating */
Addr segBase; /* base of the current segment when iterating */
Res res;
AVERT(MVFF, mvff);
AVER(base < limit);
/* Could profitably AVER that the given range is free, */
/* but the CBS doesn't provide that facility. */
if (AddrOffset(base, limit) < mvff->minSegSize)
return; /* not large enough for entire segments */
arena = PoolArena(MVFF2Pool(mvff));
b = SegOfAddr(&seg, arena, base);
AVER(b);
segBase = SegBase(seg);
segLimit = SegLimit(seg);
while(segLimit <= limit) { /* segment ends in range */
if (segBase >= base) { /* segment starts in range */
/* Must remove from free list first, in case free list */
/* is using inline data structures. */
res = CBSDelete(CBSOfMVFF(mvff), segBase, segLimit);
AVER(res == ResOK);
mvff->free -= AddrOffset(segBase, segLimit);
mvff->total -= AddrOffset(segBase, segLimit);
SegFree(seg);
}
/* Avoid calling SegNext if the next segment would fail */
/* the loop test, mainly because there might not be a */
/* next segment. */
if (segLimit == limit) /* segment ends at end of range */
break;
b = SegNext(&seg, arena, segBase);
AVER(b);
segBase = SegBase(seg);
segLimit = SegLimit(seg);
}
return;
}
/* MVFFFindFirstFree -- Finds the first (or last) suitable free block
*
* Finds a free block of the given (pool aligned) size, according
* to a first (or last) fit policy controlled by the MVFF fields
* firstFit, slotHigh (for whether to allocate the top or bottom
* portion of a larger block).
*
* Will return FALSE if the free list has no large enough block.
* In particular, will not attempt to allocate a new segment.
*/
static Bool MVFFFindFirstFree(Addr *baseReturn, Addr *limitReturn,
MVFF mvff, Size size)
{
Bool foundBlock;
CBSFindDelete findDelete;
AVER(baseReturn != NULL);
AVER(limitReturn != NULL);
AVERT(MVFF, mvff);
AVER(size > 0);
AVER(SizeIsAligned(size, PoolAlignment(MVFF2Pool(mvff))));
findDelete = mvff->slotHigh ? CBSFindDeleteHIGH : CBSFindDeleteLOW;
foundBlock =
(mvff->firstFit ? CBSFindFirst : CBSFindLast)
(baseReturn, limitReturn, CBSOfMVFF(mvff), size, findDelete);
if (foundBlock)
mvff->free -= size;
return foundBlock;
}
/* MVFFFindFirstFree -- Finds the first (or last) suitable free block
*
* Finds a free block of the given (pool aligned) size, according
* to a first (or last) fit policy controlled by the MVFF fields
* firstFit, slotHigh (for whether to allocate the top or bottom
* portion of a larger block).
*
* Will return FALSE if the free list has no large enough block.
* In particular, will not attempt to allocate a new segment.
*/
static Bool MVFFFindFirstFree(Addr *baseReturn, Addr *limitReturn,
MVFF mvff, Size size)
{
Bool foundBlock;
FindDelete findDelete;
RangeStruct range, oldRange;
AVER(baseReturn != NULL);
AVER(limitReturn != NULL);
AVERT(MVFF, mvff);
AVER(size > 0);
AVER(SizeIsAligned(size, PoolAlignment(MVFF2Pool(mvff))));
FreelistFlushToCBS(FreelistOfMVFF(mvff), CBSOfMVFF(mvff));
findDelete = mvff->slotHigh ? FindDeleteHIGH : FindDeleteLOW;
foundBlock =
(mvff->firstFit ? CBSFindFirst : CBSFindLast)
(&range, &oldRange, CBSOfMVFF(mvff), size, findDelete);
if (!foundBlock) {
/* Failed to find a block in the CBS: try the emergency free list
* as well. */
foundBlock =
(mvff->firstFit ? FreelistFindFirst : FreelistFindLast)
(&range, &oldRange, FreelistOfMVFF(mvff), size, findDelete);
}
if (foundBlock) {
*baseReturn = RangeBase(&range);
*limitReturn = RangeLimit(&range);
mvff->free -= size;
}
return foundBlock;
}
/* MVFFFreeSegs -- Free segments from given range
*
* Given a free range, attempts to find entire segments within
* it, and returns them to the arena, updating total size counter.
*
* This is usually called immediately after MVFFAddToFreeList.
* It is not combined with MVFFAddToFreeList because the latter
* is also called when new segments are added under MVFFAlloc.
*/
static void MVFFFreeSegs(MVFF mvff, Addr base, Addr limit)
{
Seg seg = NULL; /* suppress "may be used uninitialized" */
Arena arena;
Bool b;
Addr segLimit; /* limit of the current segment when iterating */
Addr segBase; /* base of the current segment when iterating */
Res res;
AVERT(MVFF, mvff);
AVER(base < limit);
/* Could profitably AVER that the given range is free, */
/* but the CBS doesn't provide that facility. */
if (AddrOffset(base, limit) < mvff->minSegSize)
return; /* not large enough for entire segments */
arena = PoolArena(MVFF2Pool(mvff));
b = SegOfAddr(&seg, arena, base);
AVER(b);
segBase = SegBase(seg);
segLimit = SegLimit(seg);
while(segLimit <= limit) { /* segment ends in range */
if (segBase >= base) { /* segment starts in range */
RangeStruct range, oldRange;
RangeInit(&range, segBase, segLimit);
res = CBSDelete(&oldRange, CBSOfMVFF(mvff), &range);
if (res == ResOK) {
mvff->free -= RangeSize(&range);
} else if (ResIsAllocFailure(res)) {
/* CBS ran out of memory for splay nodes, which must mean that
* there were fragments on both sides: see
* <design/cbs/#function.cbs.delete.fail>. Handle this by
* deleting the whole of oldRange (which requires no
* allocation) and re-inserting the fragments. */
RangeStruct oldRange2;
res = CBSDelete(&oldRange2, CBSOfMVFF(mvff), &oldRange);
AVER(res == ResOK);
AVER(RangesEqual(&oldRange2, &oldRange));
mvff->free -= RangeSize(&oldRange);
AVER(RangeBase(&oldRange) != segBase);
{
Addr leftBase = RangeBase(&oldRange);
Addr leftLimit = segBase;
res = MVFFAddToFreeList(&leftBase, &leftLimit, mvff);
}
AVER(RangeLimit(&oldRange) != segLimit);
{
Addr rightBase = segLimit;
Addr rightLimit = RangeLimit(&oldRange);
res = MVFFAddToFreeList(&rightBase, &rightLimit, mvff);
}
} else if (res == ResFAIL) {
/* Not found in the CBS: must be found in the Freelist. */
res = FreelistDelete(&oldRange, FreelistOfMVFF(mvff), &range);
AVER(res == ResOK);
mvff->free -= RangeSize(&range);
}
AVER(res == ResOK);
AVER(RangesNest(&oldRange, &range));
/* Can't free the segment earlier, because if it was on the
* Freelist rather than the CBS then it likely contains data
* that needs to be read in order to update the Freelist. */
SegFree(seg);
mvff->total -= RangeSize(&range);
}
/* Avoid calling SegNext if the next segment would fail */
/* the loop test, mainly because there might not be a */
/* next segment. */
if (segLimit == limit) /* segment ends at end of range */
break;
b = SegFindAboveAddr(&seg, arena, segBase);
AVER(b);
segBase = SegBase(seg);
segLimit = SegLimit(seg);
}
return;
}
