Re: [PATCH net 0/3] Fix for BPF devmap percpu allocation splat

Hi Daniel and Tejun,

On Wed, Oct 18, 2017 at 06:25:26AM -0700, Tejun Heo wrote:

quoted

Daniel Borkmann (3):
  mm, percpu: add support for __GFP_NOWARN flag

This looks fine.

Looks good to me too.

quoted

  bpf: fix splat for illegal devmap percpu allocation
  bpf: do not test for PCPU_MIN_UNIT_SIZE before percpu allocations

These look okay too but if it helps percpu allocator can expose the
maximum size / alignment supported to take out the guessing game too.

I can add this once we've addressed the below if we want to.

Also, the reason why PCPU_MIN_UNIT_SIZE is what it is is because
nobody needed anything bigger.  Increasing the size doesn't really
cost much at least on 64bit archs.  Is that something we want to be
considering?

I'm not sure I see the reason we can't match the minimum allocation size
with the unit size? It seems weird to arbitrate the maximum allocation
size given a lower bound on the unit size.

Thanks,
Dennis