kernel/linux.git/include/net/page_pool.h, branch v5.13.16

mm: fix struct page layout on 32-bit systems

2021-05-15T02:41:32+00:00

32-bit architectures which expect 8-byte alignment for 8-byte integers and need 64-bit DMA addresses (arm, mips, ppc) had their struct page inadvertently expanded in 2019. When the dma_addr_t was added, it forced the alignment of the union to 8 bytes, which inserted a 4 byte gap between 'flags' and the union. Fix this by storing the dma_addr_t in one or two adjacent unsigned longs. This restores the alignment to that of an unsigned long. We always store the low bits in the first word to prevent the PageTail bit from being inadvertently set on a big endian platform. If that happened, get_user_pages_fast() racing against a page which was freed and reallocated to the page_pool could dereference a bogus compound_head(), which would be hard to trace back to this cause. Link: https://lkml.kernel.org/r/20210510153211.1504886-1-willy@infradead.org Fixes: c25fff7171be ("mm: add dma_addr_t to struct page") Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Ilias Apalodimas Acked-by: Jesper Dangaard Brouer Acked-by: Vlastimil Babka Tested-by: Matteo Croce Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

net: page_pool: use alloc_pages_bulk in refill code path

2021-04-30T18:20:43+00:00

There are cases where the page_pool need to refill with pages from the page allocator. Some workloads cause the page_pool to release pages instead of recycling these pages. For these workload it can improve performance to bulk alloc pages from the page-allocator to refill the alloc cache. For XDP-redirect workload with 100G mlx5 driver (that use page_pool) redirecting xdp_frame packets into a veth, that does XDP_PASS to create an SKB from the xdp_frame, which then cannot return the page to the page_pool. Performance results under GitHub xdp-project[1]: [1] https://github.com/xdp-project/xdp-project/blob/master/areas/mem/page_pool06_alloc_pages_bulk.org Mel: The patch "net: page_pool: convert to use alloc_pages_bulk_array variant" was squashed with this patch. From the test page, the array variant was superior with one of the test results as follows. Kernel XDP stats CPU pps Delta Baseline XDP-RX CPU total 3,771,046 n/a List XDP-RX CPU total 3,940,242 +4.49% Array XDP-RX CPU total 4,249,224 +12.68% Link: https://lkml.kernel.org/r/20210325114228.27719-10-mgorman@techsingularity.net Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Mel Gorman Reviewed-by: Alexander Lobakin Cc: Alexander Duyck Cc: Christoph Hellwig Cc: Chuck Lever Cc: David Miller Cc: Ilias Apalodimas Cc: Matthew Wilcox (Oracle) Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

net: page_pool: Add bulk support for ptr_ring

2020-11-14T01:29:00+00:00

Introduce the capability to batch page_pool ptr_ring refill since it is usually run inside the driver NAPI tx completion loop. Suggested-by: Jesper Dangaard Brouer Co-developed-by: Jesper Dangaard Brouer Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Lorenzo Bianconi Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Ilias Apalodimas Link: https://lore.kernel.org/bpf/08dd249c9522c001313f520796faa777c4089e1c.1605267335.git.lorenzo@kernel.org

net: page_pool: API cleanup and comments

2020-02-20T18:09:25+00:00

Functions starting with __ usually indicate those which are exported, but should not be called directly. Update some of those declared in the API and make it more readable. page_pool_unmap_page() and page_pool_release_page() were doing exactly the same thing calling __page_pool_clean_page(). Let's rename __page_pool_clean_page() to page_pool_release_page() and export it in order to show up on perf logs and get rid of page_pool_unmap_page(). Finally rename __page_pool_put_page() to page_pool_put_page() since we can now directly call it from drivers and rename the existing page_pool_put_page() to page_pool_put_full_page() since they do the same thing but the latter is trying to sync the full DMA area. This patch also updates netsec, mvneta and stmmac drivers which use those functions. Suggested-by: Jonathan Lemon Acked-by: Toke Høiland-Jørgensen Acked-by: Jesper Dangaard Brouer Signed-off-by: Ilias Apalodimas Signed-off-by: David S. Miller

net: page_pool: add the possibility to sync DMA memory for device

2019-11-20T20:34:28+00:00

Introduce the following parameters in order to add the possibility to sync DMA memory for device before putting allocated pages in the page_pool caches: - PP_FLAG_DMA_SYNC_DEV: if set in page_pool_params flags, all pages that the driver gets from page_pool will be DMA-synced-for-device according to the length provided by the device driver. Please note DMA-sync-for-CPU is still device driver responsibility - offset: DMA address offset where the DMA engine starts copying rx data - max_len: maximum DMA memory size page_pool is allowed to flush. This is currently used in __page_pool_alloc_pages_slow routine when pages are allocated from page allocator These parameters are supposed to be set by device drivers. This optimization reduces the length of the DMA-sync-for-device. The optimization is valid because pages are initially DMA-synced-for-device as defined via max_len. At RX time, the driver will perform a DMA-sync-for-CPU on the memory for the packet length. What is important is the memory occupied by packet payload, because this is the area CPU is allowed to read and modify. As we don't track cache-lines written into by the CPU, simply use the packet payload length as dma_sync_size at page_pool recycle time. This also take into account any tail-extend. Tested-by: Matteo Croce Signed-off-by: Lorenzo Bianconi Signed-off-by: Jesper Dangaard Brouer Acked-by: Ilias Apalodimas Signed-off-by: David S. Miller

page_pool: Add API to update numa node

2019-11-20T19:47:36+00:00

Add page_pool_update_nid() to be called by page pool consumers when they detect numa node changes. It will update the page pool nid value to start allocating from the new effective numa node. This is to mitigate page pool allocating pages from a wrong numa node, where the pool was originally allocated, and holding on to pages that belong to a different numa node, which causes performance degradation. For pages that are already being consumed and could be returned to the pool by the consumer, in next patch we will add a check per page to avoid recycling them back to the pool and return them to the page allocator. Signed-off-by: Saeed Mahameed Acked-by: Jonathan Lemon Reviewed-by: Ilias Apalodimas Acked-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller

page_pool: add destroy attempts counter and rename tracepoint

2019-11-19T01:03:18+00:00

When Jonathan change the page_pool to become responsible to its own shutdown via deferred work queue, then the disconnect_cnt counter was removed from xdp memory model tracepoint. This patch change the page_pool_inflight tracepoint name to page_pool_release, because it reflects the new responsability better. And it reintroduces a counter that reflect the number of times page_pool_release have been tried. The counter is also used by the code, to only empty the alloc cache once. With a stuck work queue running every second and counter being 64-bit, it will overrun in approx 584 billion years. For comparison, Earth lifetime expectancy is 7.5 billion years, before the Sun will engulf, and destroy, the Earth. Signed-off-by: Jesper Dangaard Brouer Acked-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller

page_pool: do not release pool until inflight == 0.

2019-11-16T20:39:10+00:00

The page pool keeps track of the number of pages in flight, and it isn't safe to remove the pool until all pages are returned. Disallow removing the pool until all pages are back, so the pool is always available for page producers. Make the page pool responsible for its own delayed destruction instead of relying on XDP, so the page pool can be used without the xdp memory model. When all pages are returned, free the pool and notify xdp if the pool is registered with the xdp memory system. Have the callback perform a table walk since some drivers (cpsw) may share the pool among multiple xdp_rxq_info. Note that the increment of pages_state_release_cnt may result in inflight == 0, resulting in the pool being released. Fixes: d956a048cd3f ("xdp: force mem allocator removal and periodic warning") Signed-off-by: Jonathan Lemon Acked-by: Jesper Dangaard Brouer Acked-by: Ilias Apalodimas Signed-off-by: David S. Miller

net: core: page_pool: add user refcnt and reintroduce page_pool_destroy

2019-07-08T21:58:04+00:00

Jesper recently removed page_pool_destroy() (from driver invocation) and moved shutdown and free of page_pool into xdp_rxq_info_unreg(), in-order to handle in-flight packets/pages. This created an asymmetry in drivers create/destroy pairs. This patch reintroduce page_pool_destroy and add page_pool user refcnt. This serves the purpose to simplify drivers error handling as driver now drivers always calls page_pool_destroy() and don't need to track if xdp_rxq_info_reg_mem_model() was unsuccessful. This could be used for a special cases where a single RX-queue (with a single page_pool) provides packets for two net_device'es, and thus needs to register the same page_pool twice with two xdp_rxq_info structures. This patch is primarily to ease API usage for drivers. The recently merged netsec driver, actually have a bug in this area, which is solved by this API change. This patch is a modified version of Ivan Khoronzhuk's original patch. Link: https://lore.kernel.org/netdev/20190625175948.24771-2-ivan.khoronzhuk@linaro.org/ Fixes: 5c67bf0ec4d0 ("net: netsec: Use page_pool API") Signed-off-by: Jesper Dangaard Brouer Reviewed-by: Ilias Apalodimas Acked-by: Jesper Dangaard Brouer Reviewed-by: Saeed Mahameed Signed-off-by: Ivan Khoronzhuk Signed-off-by: David S. Miller

net: page_pool: add helper function for retrieving dma direction

2019-07-02T02:27:08+00:00

Since the dma direction is stored in page pool params, offer an API helper for driver that choose not to keep track of it locally Signed-off-by: Ilias Apalodimas Acked-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller