Re: [RFC PATCH 1/5] mm: intorduce __GFP_UNMAPPED and unmapped_alloc()

[Kent Overstreet]

On Thu, May 18, 2023 at 01:03:28PM -0700, Song Liu wrote:
> If we use compound_order(), we will round up to power of 2 for all
> allocations. Does this mean we will use 4MiB for a 2.1MiB allocation?

Yes. This means we lose on average 33% - I believe, someone with better
statistics might correct me - to internal fragmentation. But the buddy
allocator will be better at avoiding and dealing with external
fragmentation over time.