Re: [PATCH v2 RFC/RFT 0/5] Save single pages from CMA area

[Christoph Hellwig]

On Tue, Mar 26, 2019 at 04:01:26PM -0700, Nicolin Chen wrote:
> This series of patches try to save single pages from CMA area bypassing
> all CMA single page alloctions and allocating normal pages instead, as
> all addresses within one single page are contiguous.
> 
> We had once applied the PATCH-5 but reverted it as actually not all the
> callers handled the fallback allocations. Per Robin's suggestion, let's
> stuff alloc_pages()/free_page() fallbacks to those callers before having
> PATCH-5.

Given the problems this has caused so far I'd like to see a good
explanation of why this optimization is so important that all the churn
is even worth it..