Re: [PATCH v6 0/3] Improve zero-length memzone allocation

[Thomas Monjalon <thomas@monjalon.net>]

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