[dpdk-dev] [PATCH v3 0/3] Improve zero-length memzone allocation

Anatoly Burakov anatoly.burakov at intel.com
Thu May 3 19:17:58 CEST 2018


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 biggest free IOVA-contiguous element to stats
  malloc: allow reserving biggest element
  memzone: improve zero-length memzone reserve

 lib/librte_eal/common/eal_common_memzone.c  |  62 ++---------
 lib/librte_eal/common/include/rte_malloc.h  |   1 +
 lib/librte_eal/common/include/rte_memzone.h |  18 ++++
 lib/librte_eal/common/malloc_elem.c         |  77 ++++++++++++++
 lib/librte_eal/common/malloc_elem.h         |   6 ++
 lib/librte_eal/common/malloc_heap.c         | 137 ++++++++++++++++++++++++
 lib/librte_eal/common/malloc_heap.h         |   4 +
 lib/librte_eal/common/rte_malloc.c          |   2 +
 test/test/test_memzone.c                    | 157 +++++++++++++++-------------
 9 files changed, 342 insertions(+), 122 deletions(-)

-- 
2.7.4


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