On Sat, 15 Apr 2023 14:25:29 +0000 Haiyang Zhang wrote: > > Allocating frag larger than a page is not safe. > > I saw other drivers doing this - use napi_alloc_frag for size bigger than a page. > And it returns compound page. Why it's not safe? Should we use other allocator > when need compound pages? I believe so. There was a thread about this within the last year. Someone was trying to fix the page frag allocator to not fall back to order 0 pages in case of failure if requested size is > PAGE_SIZE. But there was push back and folks were saying that it's simply not a case supported by the frag allocator. 🤷️ > > Frag allocator falls back to allocating single pages, doesn't it? > > Actually I checked it. Compound page is still returned for size smaller than PAGE_SIZE, > so I used single page allocation for that. https://elixir.bootlin.com/linux/v6.3-rc6/source/mm/page_alloc.c#L5723 Jumbo frames should really be supported as scatter transfers, if possible.
