| /* SPDX-License-Identifier: GPL-2.0 |
| * |
| * page_pool.h |
| * Author: Jesper Dangaard Brouer <netoptimizer@brouer.com> |
| * Copyright (C) 2016 Red Hat, Inc. |
| */ |
| |
| /** |
| * DOC: page_pool allocator |
| * |
| * This page_pool allocator is optimized for the XDP mode that |
| * uses one-frame-per-page, but have fallbacks that act like the |
| * regular page allocator APIs. |
| * |
| * Basic use involve replacing alloc_pages() calls with the |
| * page_pool_alloc_pages() call. Drivers should likely use |
| * page_pool_dev_alloc_pages() replacing dev_alloc_pages(). |
| * |
| * API keeps track of in-flight pages, in-order to let API user know |
| * when it is safe to dealloactor page_pool object. Thus, API users |
| * must make sure to call page_pool_release_page() when a page is |
| * "leaving" the page_pool. Or call page_pool_put_page() where |
| * appropiate. For maintaining correct accounting. |
| * |
| * API user must only call page_pool_put_page() once on a page, as it |
| * will either recycle the page, or in case of elevated refcnt, it |
| * will release the DMA mapping and in-flight state accounting. We |
| * hope to lift this requirement in the future. |
| */ |
| #ifndef _NET_PAGE_POOL_H |
| #define _NET_PAGE_POOL_H |
| |
| #include <linux/mm.h> /* Needed by ptr_ring */ |
| #include <linux/ptr_ring.h> |
| #include <linux/dma-direction.h> |
| |
| #define PP_FLAG_DMA_MAP BIT(0) /* Should page_pool do the DMA |
| * map/unmap |
| */ |
| #define PP_FLAG_DMA_SYNC_DEV BIT(1) /* If set 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 |
| */ |
| #define PP_FLAG_PAGE_FRAG BIT(2) /* for page frag feature */ |
| #define PP_FLAG_ALL (PP_FLAG_DMA_MAP |\ |
| PP_FLAG_DMA_SYNC_DEV |\ |
| PP_FLAG_PAGE_FRAG) |
| |
| /* |
| * Fast allocation side cache array/stack |
| * |
| * The cache size and refill watermark is related to the network |
| * use-case. The NAPI budget is 64 packets. After a NAPI poll the RX |
| * ring is usually refilled and the max consumed elements will be 64, |
| * thus a natural max size of objects needed in the cache. |
| * |
| * Keeping room for more objects, is due to XDP_DROP use-case. As |
| * XDP_DROP allows the opportunity to recycle objects directly into |
| * this array, as it shares the same softirq/NAPI protection. If |
| * cache is already full (or partly full) then the XDP_DROP recycles |
| * would have to take a slower code path. |
| */ |
| #define PP_ALLOC_CACHE_SIZE 128 |
| #define PP_ALLOC_CACHE_REFILL 64 |
| struct pp_alloc_cache { |
| u32 count; |
| struct page *cache[PP_ALLOC_CACHE_SIZE]; |
| }; |
| |
| struct page_pool_params { |
| unsigned int flags; |
| unsigned int order; |
| unsigned int pool_size; |
| int nid; /* Numa node id to allocate from pages from */ |
| struct device *dev; /* device, for DMA pre-mapping purposes */ |
| enum dma_data_direction dma_dir; /* DMA mapping direction */ |
| unsigned int max_len; /* max DMA sync memory size */ |
| unsigned int offset; /* DMA addr offset */ |
| void (*init_callback)(struct page *page, void *arg); |
| void *init_arg; |
| }; |
| |
| #ifdef CONFIG_PAGE_POOL_STATS |
| struct page_pool_alloc_stats { |
| u64 fast; /* fast path allocations */ |
| u64 slow; /* slow-path order 0 allocations */ |
| u64 slow_high_order; /* slow-path high order allocations */ |
| u64 empty; /* failed refills due to empty ptr ring, forcing |
| * slow path allocation |
| */ |
| u64 refill; /* allocations via successful refill */ |
| u64 waive; /* failed refills due to numa zone mismatch */ |
| }; |
| |
| struct page_pool_recycle_stats { |
| u64 cached; /* recycling placed page in the cache. */ |
| u64 cache_full; /* cache was full */ |
| u64 ring; /* recycling placed page back into ptr ring */ |
| u64 ring_full; /* page was released from page-pool because |
| * PTR ring was full. |
| */ |
| u64 released_refcnt; /* page released because of elevated |
| * refcnt |
| */ |
| }; |
| |
| /* This struct wraps the above stats structs so users of the |
| * page_pool_get_stats API can pass a single argument when requesting the |
| * stats for the page pool. |
| */ |
| struct page_pool_stats { |
| struct page_pool_alloc_stats alloc_stats; |
| struct page_pool_recycle_stats recycle_stats; |
| }; |
| |
| int page_pool_ethtool_stats_get_count(void); |
| u8 *page_pool_ethtool_stats_get_strings(u8 *data); |
| u64 *page_pool_ethtool_stats_get(u64 *data, void *stats); |
| |
| /* |
| * Drivers that wish to harvest page pool stats and report them to users |
| * (perhaps via ethtool, debugfs, or another mechanism) can allocate a |
| * struct page_pool_stats call page_pool_get_stats to get stats for the specified pool. |
| */ |
| bool page_pool_get_stats(struct page_pool *pool, |
| struct page_pool_stats *stats); |
| #else |
| |
| static inline int page_pool_ethtool_stats_get_count(void) |
| { |
| return 0; |
| } |
| |
| static inline u8 *page_pool_ethtool_stats_get_strings(u8 *data) |
| { |
| return data; |
| } |
| |
| static inline u64 *page_pool_ethtool_stats_get(u64 *data, void *stats) |
| { |
| return data; |
| } |
| |
| #endif |
| |
| struct page_pool { |
| struct page_pool_params p; |
| |
| struct delayed_work release_dw; |
| void (*disconnect)(void *); |
| unsigned long defer_start; |
| unsigned long defer_warn; |
| |
| u32 pages_state_hold_cnt; |
| unsigned int frag_offset; |
| struct page *frag_page; |
| long frag_users; |
| |
| #ifdef CONFIG_PAGE_POOL_STATS |
| /* these stats are incremented while in softirq context */ |
| struct page_pool_alloc_stats alloc_stats; |
| #endif |
| u32 xdp_mem_id; |
| |
| /* |
| * Data structure for allocation side |
| * |
| * Drivers allocation side usually already perform some kind |
| * of resource protection. Piggyback on this protection, and |
| * require driver to protect allocation side. |
| * |
| * For NIC drivers this means, allocate a page_pool per |
| * RX-queue. As the RX-queue is already protected by |
| * Softirq/BH scheduling and napi_schedule. NAPI schedule |
| * guarantee that a single napi_struct will only be scheduled |
| * on a single CPU (see napi_schedule). |
| */ |
| struct pp_alloc_cache alloc ____cacheline_aligned_in_smp; |
| |
| /* Data structure for storing recycled pages. |
| * |
| * Returning/freeing pages is more complicated synchronization |
| * wise, because free's can happen on remote CPUs, with no |
| * association with allocation resource. |
| * |
| * Use ptr_ring, as it separates consumer and producer |
| * effeciently, it a way that doesn't bounce cache-lines. |
| * |
| * TODO: Implement bulk return pages into this structure. |
| */ |
| struct ptr_ring ring; |
| |
| #ifdef CONFIG_PAGE_POOL_STATS |
| /* recycle stats are per-cpu to avoid locking */ |
| struct page_pool_recycle_stats __percpu *recycle_stats; |
| #endif |
| atomic_t pages_state_release_cnt; |
| |
| /* A page_pool is strictly tied to a single RX-queue being |
| * protected by NAPI, due to above pp_alloc_cache. This |
| * refcnt serves purpose is to simplify drivers error handling. |
| */ |
| refcount_t user_cnt; |
| |
| u64 destroy_cnt; |
| }; |
| |
| struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp); |
| |
| static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool) |
| { |
| gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN); |
| |
| return page_pool_alloc_pages(pool, gfp); |
| } |
| |
| struct page *page_pool_alloc_frag(struct page_pool *pool, unsigned int *offset, |
| unsigned int size, gfp_t gfp); |
| |
| static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool, |
| unsigned int *offset, |
| unsigned int size) |
| { |
| gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN); |
| |
| return page_pool_alloc_frag(pool, offset, size, gfp); |
| } |
| |
| /* get the stored dma direction. A driver might decide to treat this locally and |
| * avoid the extra cache line from page_pool to determine the direction |
| */ |
| static |
| inline enum dma_data_direction page_pool_get_dma_dir(struct page_pool *pool) |
| { |
| return pool->p.dma_dir; |
| } |
| |
| bool page_pool_return_skb_page(struct page *page); |
| |
| struct page_pool *page_pool_create(const struct page_pool_params *params); |
| |
| struct xdp_mem_info; |
| |
| #ifdef CONFIG_PAGE_POOL |
| void page_pool_destroy(struct page_pool *pool); |
| void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *), |
| struct xdp_mem_info *mem); |
| void page_pool_release_page(struct page_pool *pool, struct page *page); |
| void page_pool_put_page_bulk(struct page_pool *pool, void **data, |
| int count); |
| #else |
| static inline void page_pool_destroy(struct page_pool *pool) |
| { |
| } |
| |
| static inline void page_pool_use_xdp_mem(struct page_pool *pool, |
| void (*disconnect)(void *), |
| struct xdp_mem_info *mem) |
| { |
| } |
| static inline void page_pool_release_page(struct page_pool *pool, |
| struct page *page) |
| { |
| } |
| |
| static inline void page_pool_put_page_bulk(struct page_pool *pool, void **data, |
| int count) |
| { |
| } |
| #endif |
| |
| void page_pool_put_defragged_page(struct page_pool *pool, struct page *page, |
| unsigned int dma_sync_size, |
| bool allow_direct); |
| |
| /* pp_frag_count represents the number of writers who can update the page |
| * either by updating skb->data or via DMA mappings for the device. |
| * We can't rely on the page refcnt for that as we don't know who might be |
| * holding page references and we can't reliably destroy or sync DMA mappings |
| * of the fragments. |
| * |
| * When pp_frag_count reaches 0 we can either recycle the page if the page |
| * refcnt is 1 or return it back to the memory allocator and destroy any |
| * mappings we have. |
| */ |
| static inline void page_pool_fragment_page(struct page *page, long nr) |
| { |
| atomic_long_set(&page->pp_frag_count, nr); |
| } |
| |
| static inline long page_pool_defrag_page(struct page *page, long nr) |
| { |
| long ret; |
| |
| /* If nr == pp_frag_count then we have cleared all remaining |
| * references to the page. No need to actually overwrite it, instead |
| * we can leave this to be overwritten by the calling function. |
| * |
| * The main advantage to doing this is that an atomic_read is |
| * generally a much cheaper operation than an atomic update, |
| * especially when dealing with a page that may be partitioned |
| * into only 2 or 3 pieces. |
| */ |
| if (atomic_long_read(&page->pp_frag_count) == nr) |
| return 0; |
| |
| ret = atomic_long_sub_return(nr, &page->pp_frag_count); |
| WARN_ON(ret < 0); |
| return ret; |
| } |
| |
| static inline bool page_pool_is_last_frag(struct page_pool *pool, |
| struct page *page) |
| { |
| /* If fragments aren't enabled or count is 0 we were the last user */ |
| return !(pool->p.flags & PP_FLAG_PAGE_FRAG) || |
| (page_pool_defrag_page(page, 1) == 0); |
| } |
| |
| static inline void page_pool_put_page(struct page_pool *pool, |
| struct page *page, |
| unsigned int dma_sync_size, |
| bool allow_direct) |
| { |
| /* When page_pool isn't compiled-in, net/core/xdp.c doesn't |
| * allow registering MEM_TYPE_PAGE_POOL, but shield linker. |
| */ |
| #ifdef CONFIG_PAGE_POOL |
| if (!page_pool_is_last_frag(pool, page)) |
| return; |
| |
| page_pool_put_defragged_page(pool, page, dma_sync_size, allow_direct); |
| #endif |
| } |
| |
| /* Same as above but will try to sync the entire area pool->max_len */ |
| static inline void page_pool_put_full_page(struct page_pool *pool, |
| struct page *page, bool allow_direct) |
| { |
| page_pool_put_page(pool, page, -1, allow_direct); |
| } |
| |
| /* Same as above but the caller must guarantee safe context. e.g NAPI */ |
| static inline void page_pool_recycle_direct(struct page_pool *pool, |
| struct page *page) |
| { |
| page_pool_put_full_page(pool, page, true); |
| } |
| |
| #define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \ |
| (sizeof(dma_addr_t) > sizeof(unsigned long)) |
| |
| static inline dma_addr_t page_pool_get_dma_addr(struct page *page) |
| { |
| dma_addr_t ret = page->dma_addr; |
| |
| if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT) |
| ret |= (dma_addr_t)page->dma_addr_upper << 16 << 16; |
| |
| return ret; |
| } |
| |
| static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr) |
| { |
| page->dma_addr = addr; |
| if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT) |
| page->dma_addr_upper = upper_32_bits(addr); |
| } |
| |
| static inline bool is_page_pool_compiled_in(void) |
| { |
| #ifdef CONFIG_PAGE_POOL |
| return true; |
| #else |
| return false; |
| #endif |
| } |
| |
| static inline bool page_pool_put(struct page_pool *pool) |
| { |
| return refcount_dec_and_test(&pool->user_cnt); |
| } |
| |
| /* Caller must provide appropriate safe context, e.g. NAPI. */ |
| void page_pool_update_nid(struct page_pool *pool, int new_nid); |
| static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid) |
| { |
| if (unlikely(pool->p.nid != new_nid)) |
| page_pool_update_nid(pool, new_nid); |
| } |
| |
| static inline void page_pool_ring_lock(struct page_pool *pool) |
| __acquires(&pool->ring.producer_lock) |
| { |
| if (in_softirq()) |
| spin_lock(&pool->ring.producer_lock); |
| else |
| spin_lock_bh(&pool->ring.producer_lock); |
| } |
| |
| static inline void page_pool_ring_unlock(struct page_pool *pool) |
| __releases(&pool->ring.producer_lock) |
| { |
| if (in_softirq()) |
| spin_unlock(&pool->ring.producer_lock); |
| else |
| spin_unlock_bh(&pool->ring.producer_lock); |
| } |
| |
| #endif /* _NET_PAGE_POOL_H */ |