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- /* SPDX-License-Identifier: GPL-2.0
- *
- * page_pool.h
- * Author: Jesper Dangaard Brouer <[email protected]>
- * 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>
- #include <linux/android_kabi.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;
- ANDROID_KABI_RESERVE(1);
- };
- 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);
- 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);
- }
- #endif /* _NET_PAGE_POOL_H */
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