On 06/24/2010 02:34 PM, Andre Przywara wrote:
Non-anonymous memory doesn't work well with ksm and transparent
hugepages. Is it possible to use anonymous memory rather than file
backed?
I'd prefer non-file backed, too. But that is how the current huge
pages implementation is done. We could use MAP_HUGETLB and declare
NUMA _and_ huge pages as 2.6.32+ only. Unfortunately I didn't find an
easy way to detect the presence of the MAP_HUGETLB flag. If the kernel
does not support it, it seems that mmap silently ignores it and uses
4KB pages instead.
That sucks, unfortunately it is normal practice. However it is a soft
failure, everything works just a bit slower. So it's probably acceptable.
To avoid this I'd like to see the pinning done from within QEMU. I
am not sure whether calling numactl via system() and friends is OK,
I'd prefer to run the syscalls directly (like in patch 3/3) and pull
the necessary options into the -numa pin,... command line. We could
mimic numactl's syntax here.
Definitely not use system(), but IIRC numactl has a library interface?
Right, that is what I include in patch 3/3 and use. I got the
impression Anthony wanted to avoid reimplementing parts of numactl,
especially enabling the full flexibility of the command line interface
(like specifying nodes, policies and interleaving).
I want QEMU to use the library and pull the necessary options into the
-numa pin,... parsing, even if this means duplicating numactl
functionality.
I agree with that. It's a lot easier to use a single tool than to try
to integrate things yourself, the unix tradition of grep | sort | uniq
-c | sort -n notwithstanding. Especially when one of the tools is qemu.
--
error compiling committee.c: too many arguments to function
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