> -----Original Message----- > From: Jesper Dangaard Brouer <jbrouer@xxxxxxxxxx> > Sent: Friday, July 14, 2023 9:13 AM > To: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Jesper Dangaard Brouer > <jbrouer@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx> > Cc: brouer@xxxxxxxxxx; linux-hyperv@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; > Dexuan Cui <decui@xxxxxxxxxxxxx>; KY Srinivasan <kys@xxxxxxxxxxxxx>; Paul > Rosswurm <paulros@xxxxxxxxxxxxx>; olaf@xxxxxxxxx; vkuznets@xxxxxxxxxx; > davem@xxxxxxxxxxxxx; wei.liu@xxxxxxxxxx; edumazet@xxxxxxxxxx; > pabeni@xxxxxxxxxx; leon@xxxxxxxxxx; Long Li <longli@xxxxxxxxxxxxx>; > ssengar@xxxxxxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx; > daniel@xxxxxxxxxxxxx; john.fastabend@xxxxxxxxx; bpf@xxxxxxxxxxxxxxx; > ast@xxxxxxxxxx; Ajay Sharma <sharmaajay@xxxxxxxxxxxxx>; hawk@xxxxxxxxxx; > tglx@xxxxxxxxxxxxx; shradhagupta@xxxxxxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx> > Subject: Re: [PATCH net-next] net: mana: Add page pool for RX buffers > > [You don't often get email from jbrouer@xxxxxxxxxx. Learn why this is > important at https://aka.ms/LearnAboutSenderIdentification ] > > On 14/07/2023 14.51, Haiyang Zhang wrote: > > > > > >> -----Original Message----- > >> From: Jesper Dangaard Brouer <jbrouer@xxxxxxxxxx> > >> On 14/07/2023 05.53, Jakub Kicinski wrote: > >>> On Thu, 13 Jul 2023 14:48:45 +0000 Haiyang Zhang wrote: > >>>> Add page pool for RX buffers for faster buffer cycle and reduce CPU > >>>> usage. > >>>> > >>>> Get an extra ref count of a page after allocation, so after upper > >>>> layers put the page, it's still referenced by the pool. We can reuse > >>>> it as RX buffer without alloc a new page. > >>> > >>> Please use the real page_pool API from include/net/page_pool.h > >>> We've moved past every driver reinventing the wheel, sorry. > >> > >> +1 > >> > >> Quoting[1]: Documentation/networking/page_pool.rst > >> > >> Basic use involves replacing alloc_pages() calls with the > >> page_pool_alloc_pages() call. > >> Drivers should use page_pool_dev_alloc_pages() replacing > >> dev_alloc_pages(). > > > > Thank Jakub and Jesper for the reviews. > > I'm aware of the page_pool.rst doc, and actually tried it before this > > patch, but I got lower perf. If I understand correctly, we should call > > page_pool_release_page() before passing the SKB to napi_gro_receive(). > > > > I found the page_pool_dev_alloc_pages() goes through the slow path, > > because the page_pool_release_page() let the page leave the pool. > > > > Do we have to call page_pool_release_page() before passing the SKB > > to napi_gro_receive()? Any better way to recycle the pages from the > > upper layer of non-XDP case? > > > > Today SKB "upper layers" can recycle page_pool backed packet data/page. > > Just use skb_mark_for_recycle(skb), then you don't need > page_pool_release_page(). Will do. Thanks a lot! - Haiyang
