[dpdk-dev] [PATCH 0/7] fix DMA mask check

Alejandro Lucero alejandro.lucero at netronome.com
Wed Oct 31 18:29:24 CET 2018

A patchset sent introducing DMA mask checks has several critical
issues precluding apps to execute. The patchset was reviewed and
finally accepted after three versions. Obviously it did not go 
through the proper testing what can be explained, at least from my
side, due to the big changes to the memory initialization code these
last months. It turns out the patchset did work with legacy memory
and I'm afraid that was mainly my testing.

This patchset should solve the main problems reported:

 - deadlock duriing initialization
 - segmentation fault with secondary processes

For solving the deadlock, a new API is introduced:


making the previous rte_mem_check_dma_mask the one those new functions
end calling. A boolean param is used for calling rte_memseg_walk thread
safe or thread unsafe. This second option is needed for avoiding the 

For the secondary processes problem, the call to check the dma mask is
avoided from code being executed before the memory initialization. 
Instead, a new API function, rte_mem_set_dma_mask is introduced, which 
will be used in those cases. The dma mask check is done once the memory
initialization is completed.

This last change implies the IOVA mode can not be set depending on IOMMU
hardware limitations, and it is assumed IOVA VA is possible. If the dma
mask check reports a problem after memory initilization, the error 
message includes now advice for trying with --iova-mode option set to 

The patchet also includes the dma mask check for legacy memory and the 
no hugepage option.

Finally, all the DMA mask API has been updated for using the same prefix
than other EAL memory code.

An initial version of this patchset has been tested by Intel DPDK 
Validation team and it seems it solves all the problems reported. This 
final patchset has the same functionality with minor changes. I have
successfully tested the patchset with my limited testbench.

Alejandro Lucero (7):
  mem: fix call to DMA mask check
  mem: use proper prefix
  mem: add function for setting DMA mask
  bus/pci: avoid call to DMA mask check
  mem: modify error message for DMA mask check
  mem: add safe and unsafe versions for checking DMA mask
  eal/mem: use DMA mask check for legacy memory

 doc/guides/rel_notes/release_18_11.rst     |  2 +-
 drivers/bus/pci/linux/pci.c                | 11 ++++++-
 drivers/net/nfp/nfp_net.c                  |  2 +-
 lib/librte_eal/common/eal_common_memory.c  | 36 +++++++++++++++++---
 lib/librte_eal/common/include/rte_memory.h | 37 +++++++++++++++++++--
 lib/librte_eal/common/malloc_heap.c        | 38 ++++++++++++++++++----
 lib/librte_eal/linuxapp/eal/eal_memory.c   | 17 ++++++++++
 lib/librte_eal/rte_eal_version.map         |  4 ++-
 8 files changed, 131 insertions(+), 16 deletions(-)


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