Hello!

> So are you suggesting to not introduce --single-file option but instead
> --shared-mem?
> AFAIK --single-file was trying to workaround the limitation of just
> being able to map 8 fds.

 Heh, yes, you're right... Indeed, sorry, i was not patient enough, i see it 
uses hpi->hugedir instead of using /dev/shm... I was confused by the code 
path... It seemed that --single-file is an alias to --no-hugepages.
 And the patch still changes mmap() mode to SHARED unconditionally, which is 
not good in terms of backwards compability (and this is explicitly noticed in 
the cover letter).

 So, let's try to sort out...
 a) By default we should still have MAP_PRIVATE
 b) Let's say that we need --shared-mem in order to make it MAP_SHARED. This 
can be combined with --no-hugepages if necessary (this is what i tried to 
implement based on the old RFC).
 c) Let's say that --single-file uses hugetlbfs but maps everything via single 
file. This still can be combined with --shared-mem.

 wouldn't this be more clear, more straightforward and implication-free?

 And if we agree on that, we could now try to decrease number of options:
 a) We could imply MAP_SHARED if cvio is used, because shared memory is 
mandatory in this case.
 b) (c) above again raises a question: doesn't it make 
CONFIG_RTE_EAL_SIGLE_FILE_SEGMENTS obsolete? Or may be we could use that one 
instead of --single-file (however i'm not a fan of compile-time configuration 
like this)?

Kind regards,
Pavel Fedin
Senior Engineer
Samsung Electronics Research center Russia


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