Re: [PATCH v2 12/23] percpu: increase minimum percpu allocation size and align first regions

[Josef Bacik]

On Mon, Jul 24, 2017 at 07:02:09PM -0400, Dennis Zhou wrote:
> From: "Dennis Zhou (Facebook)" <dennisszhou@xxxxxxxxx>
> 
> This patch increases the minimum allocation size of percpu memory to
> 4-bytes. This change will help minimize the metadata overhead
> associated with the bitmap allocator. The assumption is that most
> allocations will be of objects or structs greater than 2 bytes with
> integers or longs being used rather than shorts.
> 
> The first chunk regions are now aligned with the minimum allocation
> size. The reserved region is expected to be set as a multiple of the
> minimum allocation size. The static region is aligned up and the delta
> is removed from the dynamic size. This works because the dynamic size is
> increased to be page aligned. If the static size is not minimum
> allocation size aligned, then there must be a gap that is added to the
> dynamic size. The dynamic size will never be smaller than the set value.
> 
> Signed-off-by: Dennis Zhou <dennisszhou@xxxxxxxxx>

Reviewed-by: Josef Bacik <jbacik@xxxxxx>

Thanks,

Josef