Re: [PATCH v2 10/23] percpu: change the number of pages marked in the first_chunk pop bitmap

[Josef Bacik]

On Mon, Jul 24, 2017 at 07:02:07PM -0400, Dennis Zhou wrote:
> From: "Dennis Zhou (Facebook)" <dennisszhou@xxxxxxxxx>
> 
> The populated bitmap represents the state of the pages the chunk serves.
> Prior, the bitmap was marked completely used as the first chunk was
> allocated and immutable. This is misleading because the first chunk may
> not be completely filled. Additionally, with moving the base_addr up in
> the previous patch, the population check no longer corresponds to what
> was being checked.
> 
> This patch modifies the population map to be only the number of pages
> the region serves and to make what it was checking correspond correctly
> again. The change is to remove any misunderstanding between the size of
> the populated bitmap and the actual size of it. The work function page
> iterators now use nr_pages for the check rather than pcpu_unit_pages
> because nr_populated is now chunk specific. Without this, the work
> function would try to populate the remainder of these chunks despite it
> not serving any more than nr_pages when nr_pages is set less than
> pcpu_unit_pages.
> 
> Signed-off-by: Dennis Zhou <dennisszhou@xxxxxxxxx>

Reviewed-by: Josef Bacik <jbacik@xxxxxx>

Thanks,

Josef