Exemplo n.º 1
0
/* 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;
}
Exemplo n.º 2
0
/* 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;
}
Exemplo n.º 3
0
/* 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;
}
Exemplo n.º 4
0
/* 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;
}
Exemplo n.º 5
0
/* 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;
}