[Lustre-discuss] copy_user_generic_c ?

[Roger Spellman]

> Yes, by all means it shouldn't need a copy on the OST - that is what
> RDMA is for.  

Agreed!

> You definitely are not running Samba exports on the OST
> node?  

Certainly not.

I can't imagine what else would be doing this on an OST.

> Your oprofile output should be able to show the callchain for the
> busiest callpaths.  Alternately, if this is active 25% of the time it
> may be enough to do "echo p > /proc/sysrq-trigger" 16 times and see
> what the resulting stacks are.  In theory 4 of them should have
> copy_{to,from}_user() at the top of the stack.

Andreas, why would 4 threads have copy_(to,from)_user at the top of the
stack?  Are certain threads supposed to be doing that on an OST?

Thanks,

Roger