On Sat, Jun 5, 2021 at 6:06 PM David Ahern <dsahern@xxxxxxxxx> wrote: > > On 6/4/21 2:42 AM, Ilias Apalodimas wrote: > > [...] > >>> + /* Driver set this to memory recycling info. Reset it on recycle. > >>> + * This will *not* work for NIC using a split-page memory model. > >>> + * The page will be returned to the pool here regardless of the > >>> + * 'flipped' fragment being in use or not. > >>> + */ > >> > >> I am not sure I understand how does the last part of comment related > >> to the code below, as there is no driver using split-page memory model > >> will reach here because those driver will not call skb_mark_for_recycle(), > >> right? > >> > > > > Yes the comment is there to prohibit people (mlx5 only actually) to add the > > recycling bit on their driver. Because if they do it will *probably* work > > but they might get random corrupted packets which will be hard to debug. > > > > What's the complexity for getting it to work with split page model? > Since 1500 is the default MTU, requiring a page per packet means a lot > of wasted memory. We could create a new memory model, e.g. MEM_TYPE_PAGE_SPLIT, and restore the behavior present in the previous versions of this serie, which is, save xdp_mem_info in struct page. As this could slightly impact the performances, this can be added in a future change when the drivers which are doing it want to use this recycling api. -- per aspera ad upstream
