On Fri, May 23, 2025 at 12:36 PM Byungchul Park <byungchul@xxxxxx> wrote: > Hi Byungchul, Thanks a lot for this work! > The MM subsystem is trying to reduce struct page to a single pointer. > The first step towards that is splitting struct page by its individual > users, as has already been done with folio and slab. This patchset does > that for netmem which is used for page pools. > > Matthew Wilcox tried and stopped the same work, you can see in: > > https://lore.kernel.org/linux-mm/20230111042214.907030-1-willy@xxxxxxxxxxxxx/ > > Mina Almasry already has done a lot fo prerequisite works by luck, he > said :). I stacked my patches on the top of his work e.i. netmem. > > I focused on removing the page pool members in struct page this time, > not moving the allocation code of page pool from net to mm. It can be > done later if needed. > > My rfc version of this work is: > > https://lore.kernel.org/all/20250509115126.63190-1-byungchul@xxxxxx/ > > There are still a lot of works to do, to remove the dependency on struct > page in the network subsystem. I will continue to work on this after > this base patchset is merged. There is a compile failure. In file included from drivers/net/ethernet/intel/libeth/rx.c:4: ./include/net/libeth/rx.h: In function ‘libeth_rx_sync_for_cpu’: ./include/net/libeth/rx.h:140:40: error: ‘struct page’ has no member named ‘pp’ 140 | page_pool_dma_sync_for_cpu(page->pp, page, fqe->offset, len); | ^~ drivers/net/ethernet/intel/libeth/rx.c: In function ‘libeth_rx_recycle_slow’: drivers/net/ethernet/intel/libeth/rx.c:210:38: error: ‘struct page’ has no member named ‘pp’ 210 | page_pool_recycle_direct(page->pp, page); | ^~ make[7]: *** [scripts/Makefile.build:203: drivers/net/ethernet/intel/libeth/rx.o] Error 1 make[6]: *** [scripts/Makefile.build:461: drivers/net/ethernet/intel/libeth] Error 2 make[5]: *** [scripts/Makefile.build:461: drivers/net/ethernet/intel] Error 2 make[5]: *** Waiting for unfinished jobs.... There are page->pp usecases in drivers/net ./drivers/net/ethernet/marvell/octeontx2/nic/otx2_txrx.c:1574: } else if (page->pp) { ./drivers/net/ethernet/freescale/fec_main.c:1046: page_pool_put_page(page->pp, page, 0, false); ./drivers/net/ethernet/freescale/fec_main.c:1584: page_pool_put_page(page->pp, page, 0, true); ./drivers/net/ethernet/freescale/fec_main.c:3351: page_pool_put_page(page->pp, page, 0, false); ./drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c:370: page_pool_recycle_direct(page->pp, page); ./drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c:395: page_pool_recycle_direct(page->pp, page); ./drivers/net/ethernet/ti/icssg/icssg_common.c:111: page_pool_recycle_direct(page->pp, swdata->data.page); ./drivers/net/ethernet/intel/idpf/idpf_txrx.c:389: page_pool_put_full_page(rx_buf->page->pp, rx_buf->page, false); ./drivers/net/ethernet/intel/idpf/idpf_txrx.c:3254: u32 hr = rx_buf->page->pp->p.offset; ./drivers/net/ethernet/intel/idpf/idpf_txrx.c:3286: dst = page_address(hdr->page) + hdr->offset + hdr->page->pp->p.offset; ./drivers/net/ethernet/intel/idpf/idpf_txrx.c:3287: src = page_address(buf->page) + buf->offset + buf->page->pp->p.offset; ./drivers/net/ethernet/intel/idpf/idpf_txrx.c:3305: u32 hr = buf->page->pp->p.offset; ./drivers/net/ethernet/intel/libeth/rx.c:210: page_pool_recycle_direct(page->pp, page); ./drivers/net/ethernet/intel/iavf/iavf_txrx.c:1200: u32 hr = rx_buffer->page->pp->p.offset; ./drivers/net/ethernet/intel/iavf/iavf_txrx.c:1217: u32 hr = rx_buffer->page->pp->p.offset; ./drivers/net/wireless/mediatek/mt76/mt76.h:1800: page_pool_put_full_page(page->pp, page, allow_direct); ./include/net/libeth/rx.h:140: page_pool_dma_sync_for_cpu(page->pp, page, fqe->offset, len); Thanks a lot! Taehee Yoo > > --- > > Changes from rfc: > 1. Rebase on net-next's main branch > https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/ > 2. Fix a build error reported by kernel test robot > https://lore.kernel.org/all/202505100932.uzAMBW1y-lkp@xxxxxxxxx/ > 3. Add given 'Reviewed-by's, thanks to Mina and Ilias > 4. Do static_assert() on the size of struct netmem_desc instead > of placing place-holder in struct page, feedbacked by Matthew > 5. Do struct_group_tagged(netmem_desc) on struct net_iov instead > of wholly renaming it to strcut netmem_desc, feedbacked by > Mina and Pavel > > Byungchul Park (18): > netmem: introduce struct netmem_desc struct_group_tagged()'ed on > struct net_iov > netmem: introduce netmem alloc APIs to wrap page alloc APIs > page_pool: use netmem alloc/put APIs in __page_pool_alloc_page_order() > page_pool: rename __page_pool_alloc_page_order() to > __page_pool_alloc_large_netmem() > page_pool: use netmem alloc/put APIs in __page_pool_alloc_pages_slow() > page_pool: rename page_pool_return_page() to page_pool_return_netmem() > page_pool: use netmem put API in page_pool_return_netmem() > page_pool: rename __page_pool_release_page_dma() to > __page_pool_release_netmem_dma() > page_pool: rename __page_pool_put_page() to __page_pool_put_netmem() > page_pool: rename __page_pool_alloc_pages_slow() to > __page_pool_alloc_netmems_slow() > mlx4: use netmem descriptor and APIs for page pool > page_pool: use netmem APIs to access page->pp_magic in > page_pool_page_is_pp() > mlx5: use netmem descriptor and APIs for page pool > netmem: use _Generic to cover const casting for page_to_netmem() > netmem: remove __netmem_get_pp() > page_pool: make page_pool_get_dma_addr() just wrap > page_pool_get_dma_addr_netmem() > netdevsim: use netmem descriptor and APIs for page pool > mm, netmem: remove the page pool members in struct page > > drivers/net/ethernet/mellanox/mlx4/en_rx.c | 46 ++++---- > drivers/net/ethernet/mellanox/mlx4/en_tx.c | 8 +- > drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 4 +- > drivers/net/ethernet/mellanox/mlx5/core/en.h | 4 +- > .../net/ethernet/mellanox/mlx5/core/en/xdp.c | 18 ++-- > .../net/ethernet/mellanox/mlx5/core/en/xdp.h | 2 +- > .../net/ethernet/mellanox/mlx5/core/en_main.c | 15 ++- > .../net/ethernet/mellanox/mlx5/core/en_rx.c | 66 ++++++------ > drivers/net/netdevsim/netdev.c | 18 ++-- > drivers/net/netdevsim/netdevsim.h | 2 +- > include/linux/mm.h | 5 +- > include/linux/mm_types.h | 11 -- > include/linux/skbuff.h | 14 +++ > include/net/netmem.h | 101 ++++++++++-------- > include/net/page_pool/helpers.h | 11 +- > net/core/page_pool.c | 97 +++++++++-------- > 16 files changed, 221 insertions(+), 201 deletions(-) > > > base-commit: f44092606a3f153bb7e6b277006b1f4a5b914cfc > -- > 2.17.1 > >
