/* MVFFBufferFill -- Fill the buffer
*
* Fill it with the largest block we can find.
*/
static Res MVFFBufferFill(Addr *baseReturn, Addr *limitReturn,
Pool pool, Buffer buffer, Size size,
Bool withReservoirPermit)
{
Res res;
MVFF mvff;
RangeStruct range, oldRange;
Bool found;
Seg seg = NULL;
AVER(baseReturn != NULL);
AVER(limitReturn != NULL);
AVERT(Pool, pool);
mvff = Pool2MVFF(pool);
AVERT(MVFF, mvff);
AVERT(Buffer, buffer);
AVER(size > 0);
AVER(SizeIsAligned(size, PoolAlignment(pool)));
AVERT(Bool, withReservoirPermit);
found = MVFFFindLargest(&range, &oldRange, mvff, size, FindDeleteENTIRE);
if (!found) {
/* Add a new segment to the free list and try again. */
res = MVFFAddSeg(&seg, mvff, size, withReservoirPermit);
if (res != ResOK)
return res;
found = MVFFFindLargest(&range, &oldRange, mvff, size, FindDeleteENTIRE);
}
AVER(found);
AVER(RangeSize(&range) >= size);
mvff->free -= RangeSize(&range);
*baseReturn = RangeBase(&range);
*limitReturn = RangeLimit(&range);
return ResOK;
}
Res RangeDescribe(Range range, mps_lib_FILE *stream, Count depth)
{
Res res;
AVERT(Range, range);
AVER(stream != NULL);
res = WriteF(stream, depth,
"Range $P {\n", (WriteFP)range,
" base: $P\n", (WriteFP)RangeBase(range),
" limit: $P\n", (WriteFP)RangeLimit(range),
" size: $U\n", (WriteFU)RangeSize(range),
"} Range $P\n", (WriteFP)range, NULL);
if (res != ResOK) {
return res;
}
return ResOK;
}
/* MVFFAddToFreeList -- Add given range to free list
*
* Updates MVFF counters for additional free space. Returns maximally
* coalesced range containing given range. Does not attempt to free
* segments (see MVFFFreeSegs).
*/
static Res MVFFAddToFreeList(Addr *baseIO, Addr *limitIO, MVFF mvff) {
Res res;
RangeStruct range, newRange;
AVER(baseIO != NULL);
AVER(limitIO != NULL);
AVERT(MVFF, mvff);
RangeInit(&range, *baseIO, *limitIO);
res = CBSInsert(&newRange, CBSOfMVFF(mvff), &range);
if (ResIsAllocFailure(res)) {
/* CBS ran out of memory for splay nodes: add range to emergency
* free list instead. */
res = FreelistInsert(&newRange, FreelistOfMVFF(mvff), &range);
}
if (res == ResOK) {
mvff->free += RangeSize(&range);
*baseIO = RangeBase(&newRange);
*limitIO = RangeLimit(&newRange);
}
return res;
}
Size (RangeSize)(Range range)
{
AVERT(Range, range);
return RangeSize(range);
}
/* 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;
}
