31/05/2018 11:50, Anatoly Burakov:

This patchset does two things. First, it enables reserving
memzones of zero-length that are IOVA-contiguous. Second,
it fixes a long-standing race condition in reserving
zero-length memzones, where malloc heap is not locked between
stats collection and reservation, and will instead allocate
biggest element on the spot.

Some limitations are added, but they are a trade-off between
not having race conditions and user convenience. It would be
possible to lock all heaps during memzone reserve for zero-
length, and that would keep the old behavior, but given how
such allocation (especially when asking for IOVA-contiguous
memory) may take a long time, a design decision was made to
keep things simple, and only check other heaps if the
current one is completely busy.

Ideas on improvement are welcome.

Anatoly Burakov (3):
  malloc: add finding biggest free IOVA-contiguous element
  malloc: allow reserving biggest element
  memzone: improve zero-length memzone reserve

Applied, thanks