In [1] & [2] & [3], there are usecases for veth and virtio_net to use frag support in page pool to reduce memory usage, and it may request different frag size depending on the head/tail room space for xdp_frame/shinfo and mtu/packet size. When the requested frag size is large enough that a single page can not be split into more than one frag, using frag support only have performance penalty because of the extra frag count handling for frag support. So this patchset provides a page pool API for the driver to allocate memory with least memory utilization and performance penalty when it doesn't know the size of memory it need beforehand. 1. https://patchwork.kernel.org/project/netdevbpf/patch/d3ae6bd3537fbce379382ac6a42f67e22f27ece2.1683896626.git.lorenzo@xxxxxxxxxx/ 2. https://patchwork.kernel.org/project/netdevbpf/patch/20230526054621.18371-3-liangchen.linux@xxxxxxxxx/ 3. https://github.com/alobakin/linux/tree/iavf-pp-frag V8: Store the dma addr on a shifted u32 instead of using dma_addr_t explicitly for 32-bit arch with 64-bit DMA. Update document according to discussion in v7. V7: Fix a compile error, a few typo and use kernel-doc syntax. V6: Add a PP_FLAG_PAGE_SPLIT_IN_DRIVER flag to fail the page_pool creation for 32-bit arch with 64-bit DMA when driver tries to do the page splitting itself, adjust the requested size to include head/tail room in veth, and rebased on the latest next-net. v5 RFC: Add a new page_pool_cache_alloc() API, and other minor change as discussed in v4. As there seems to be three comsumers that might be made use of the new API, so repost it as RFC and CC the relevant authors to see if the new API fits their need. V4. Fix a typo and add a patch to update document about frag API, PAGE_POOL_DMA_USE_PP_FRAG_COUNT is not renamed yet as we may need a different thread to discuss that. V3: Incorporate changes from the disscusion with Alexander, mostly the inline wraper, PAGE_POOL_DMA_USE_PP_FRAG_COUNT change split to separate patch and comment change. V2: Add patch to remove PP_FLAG_PAGE_FRAG flags and mention virtio_net usecase in the cover letter. V1: Drop RFC tag and page_pool_frag patch. Yunsheng Lin (6): page_pool: frag API support for 32-bit arch with 64-bit DMA page_pool: unify frag_count handling in page_pool_is_last_frag() page_pool: remove PP_FLAG_PAGE_FRAG page_pool: introduce page_pool[_cache]_alloc() API page_pool: update document about frag API net: veth: use newly added page pool API for veth with xdp Documentation/networking/page_pool.rst | 4 +- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 - .../net/ethernet/hisilicon/hns3/hns3_enet.c | 3 +- .../marvell/octeontx2/nic/otx2_common.c | 2 +- .../net/ethernet/mellanox/mlx5/core/en_main.c | 2 +- drivers/net/veth.c | 25 +- drivers/net/wireless/mediatek/mt76/mac80211.c | 2 +- include/linux/mm_types.h | 13 +- include/net/page_pool/helpers.h | 225 +++++++++++++++--- include/net/page_pool/types.h | 6 +- net/core/page_pool.c | 31 ++- net/core/skbuff.c | 2 +- 12 files changed, 240 insertions(+), 77 deletions(-) -- 2.33.0
