On Tue, Nov 9, 2021 at 3:33 AM Mike Kravetz [off-list ref] wrote:

On 11/8/21 12:16 AM, Muchun Song wrote:

quoted

On Mon, Nov 1, 2021 at 11:22 AM Muchun Song [off-list ref] wrote:

quoted

This series can minimize the overhead of struct page for 2MB HugeTLB pages
significantly. It further reduces the overhead of struct page by 12.5% for
a 2MB HugeTLB compared to the previous approach, which means 2GB per 1TB
HugeTLB. It is a nice gain. Comments and reviews are welcome. Thanks.

Hi,

Ping guys. Does anyone have any comments or suggestions
on this series?

Thanks.

I did look over the series earlier.  I have no issue with the hugetlb and
vmemmap modifications as they are enhancements to the existing
optimizations.  My primary concern is the (small) increased overhead
for the helpers as outlined in your cover letter.  Since these helpers
are not limited to hugetlb and used throughout the kernel, I would
really like to get comments from others with a better understanding of
the potential impact.

Thanks Mike. I'd like to hear others' comments about this as well.
From my point of view, maybe the (small) overhead is acceptable
since it only affects the head page, however Matthew Wilcox's folio
series could reduce this situation as well.

Looking forward to others' comments.

Thanks.

--
Mike Kravetz