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

[Alejandro Lucero <alejandro.lucero@netronome.com>]

On Wed, Oct 31, 2018 at 5:29 PM Alejandro Lucero <
alejandro.lucero@netronome.com> wrote:

> 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:
>
>  rte_mem_check_dma_mask_safe/unsafe
>
> 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
> deadlock.
>
> 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
> pa.
>
> 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(-)
>
> --
> 2.17.1
>
>
I have just realized that there is a minor problem with compiling one patch
at a time, but it does compile when all applied.

I will fix this in another version but I will wait until review and testing
has been reported.