page_pool: Add allocation stats
[linux-block.git] / include / net / page_pool.h
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1/* SPDX-License-Identifier: GPL-2.0
2 *
3 * page_pool.h
4 * Author: Jesper Dangaard Brouer <netoptimizer@brouer.com>
5 * Copyright (C) 2016 Red Hat, Inc.
6 */
7
8/**
9 * DOC: page_pool allocator
10 *
11 * This page_pool allocator is optimized for the XDP mode that
12 * uses one-frame-per-page, but have fallbacks that act like the
13 * regular page allocator APIs.
14 *
15 * Basic use involve replacing alloc_pages() calls with the
16 * page_pool_alloc_pages() call. Drivers should likely use
17 * page_pool_dev_alloc_pages() replacing dev_alloc_pages().
18 *
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19 * API keeps track of in-flight pages, in-order to let API user know
20 * when it is safe to dealloactor page_pool object. Thus, API users
21 * must make sure to call page_pool_release_page() when a page is
22 * "leaving" the page_pool. Or call page_pool_put_page() where
23 * appropiate. For maintaining correct accounting.
ff7d6b27 24 *
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25 * API user must only call page_pool_put_page() once on a page, as it
26 * will either recycle the page, or in case of elevated refcnt, it
27 * will release the DMA mapping and in-flight state accounting. We
28 * hope to lift this requirement in the future.
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29 */
30#ifndef _NET_PAGE_POOL_H
31#define _NET_PAGE_POOL_H
32
33#include <linux/mm.h> /* Needed by ptr_ring */
34#include <linux/ptr_ring.h>
35#include <linux/dma-direction.h>
36
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37#define PP_FLAG_DMA_MAP BIT(0) /* Should page_pool do the DMA
38 * map/unmap
39 */
40#define PP_FLAG_DMA_SYNC_DEV BIT(1) /* If set all pages that the driver gets
41 * from page_pool will be
42 * DMA-synced-for-device according to
43 * the length provided by the device
44 * driver.
45 * Please note DMA-sync-for-CPU is still
46 * device driver responsibility
47 */
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48#define PP_FLAG_PAGE_FRAG BIT(2) /* for page frag feature */
49#define PP_FLAG_ALL (PP_FLAG_DMA_MAP |\
50 PP_FLAG_DMA_SYNC_DEV |\
51 PP_FLAG_PAGE_FRAG)
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52
53/*
54 * Fast allocation side cache array/stack
55 *
56 * The cache size and refill watermark is related to the network
57 * use-case. The NAPI budget is 64 packets. After a NAPI poll the RX
58 * ring is usually refilled and the max consumed elements will be 64,
59 * thus a natural max size of objects needed in the cache.
60 *
61 * Keeping room for more objects, is due to XDP_DROP use-case. As
62 * XDP_DROP allows the opportunity to recycle objects directly into
63 * this array, as it shares the same softirq/NAPI protection. If
64 * cache is already full (or partly full) then the XDP_DROP recycles
65 * would have to take a slower code path.
66 */
67#define PP_ALLOC_CACHE_SIZE 128
68#define PP_ALLOC_CACHE_REFILL 64
69struct pp_alloc_cache {
70 u32 count;
be5dba25 71 struct page *cache[PP_ALLOC_CACHE_SIZE];
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72};
73
74struct page_pool_params {
75 unsigned int flags;
76 unsigned int order;
77 unsigned int pool_size;
78 int nid; /* Numa node id to allocate from pages from */
79 struct device *dev; /* device, for DMA pre-mapping purposes */
80 enum dma_data_direction dma_dir; /* DMA mapping direction */
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81 unsigned int max_len; /* max DMA sync memory size */
82 unsigned int offset; /* DMA addr offset */
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83 void (*init_callback)(struct page *page, void *arg);
84 void *init_arg;
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85};
86
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87#ifdef CONFIG_PAGE_POOL_STATS
88struct page_pool_alloc_stats {
89 u64 fast; /* fast path allocations */
90 u64 slow; /* slow-path order 0 allocations */
91 u64 slow_high_order; /* slow-path high order allocations */
92 u64 empty; /* failed refills due to empty ptr ring, forcing
93 * slow path allocation
94 */
95 u64 refill; /* allocations via successful refill */
96 u64 waive; /* failed refills due to numa zone mismatch */
97};
98#endif
99
ff7d6b27 100struct page_pool {
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101 struct page_pool_params p;
102
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103 struct delayed_work release_dw;
104 void (*disconnect)(void *);
105 unsigned long defer_start;
106 unsigned long defer_warn;
107
108 u32 pages_state_hold_cnt;
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109 unsigned int frag_offset;
110 struct page *frag_page;
111 long frag_users;
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112
113#ifdef CONFIG_PAGE_POOL_STATS
114 /* these stats are incremented while in softirq context */
115 struct page_pool_alloc_stats alloc_stats;
116#endif
64693ec7 117 u32 xdp_mem_id;
99c07c43 118
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119 /*
120 * Data structure for allocation side
121 *
122 * Drivers allocation side usually already perform some kind
123 * of resource protection. Piggyback on this protection, and
124 * require driver to protect allocation side.
125 *
126 * For NIC drivers this means, allocate a page_pool per
127 * RX-queue. As the RX-queue is already protected by
128 * Softirq/BH scheduling and napi_schedule. NAPI schedule
129 * guarantee that a single napi_struct will only be scheduled
130 * on a single CPU (see napi_schedule).
131 */
132 struct pp_alloc_cache alloc ____cacheline_aligned_in_smp;
133
134 /* Data structure for storing recycled pages.
135 *
136 * Returning/freeing pages is more complicated synchronization
137 * wise, because free's can happen on remote CPUs, with no
138 * association with allocation resource.
139 *
140 * Use ptr_ring, as it separates consumer and producer
141 * effeciently, it a way that doesn't bounce cache-lines.
142 *
143 * TODO: Implement bulk return pages into this structure.
144 */
145 struct ptr_ring ring;
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146
147 atomic_t pages_state_release_cnt;
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148
149 /* A page_pool is strictly tied to a single RX-queue being
150 * protected by NAPI, due to above pp_alloc_cache. This
151 * refcnt serves purpose is to simplify drivers error handling.
152 */
153 refcount_t user_cnt;
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154
155 u64 destroy_cnt;
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156};
157
158struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
159
160static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool)
161{
162 gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
163
164 return page_pool_alloc_pages(pool, gfp);
165}
166
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167struct page *page_pool_alloc_frag(struct page_pool *pool, unsigned int *offset,
168 unsigned int size, gfp_t gfp);
169
170static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
171 unsigned int *offset,
172 unsigned int size)
173{
174 gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
175
176 return page_pool_alloc_frag(pool, offset, size, gfp);
177}
178
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179/* get the stored dma direction. A driver might decide to treat this locally and
180 * avoid the extra cache line from page_pool to determine the direction
181 */
182static
183inline enum dma_data_direction page_pool_get_dma_dir(struct page_pool *pool)
184{
185 return pool->p.dma_dir;
186}
187
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188bool page_pool_return_skb_page(struct page *page);
189
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190struct page_pool *page_pool_create(const struct page_pool_params *params);
191
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192struct xdp_mem_info;
193
e54cfd7e 194#ifdef CONFIG_PAGE_POOL
c3f812ce 195void page_pool_destroy(struct page_pool *pool);
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196void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),
197 struct xdp_mem_info *mem);
458de8a9 198void page_pool_release_page(struct page_pool *pool, struct page *page);
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199void page_pool_put_page_bulk(struct page_pool *pool, void **data,
200 int count);
c3f812ce 201#else
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202static inline void page_pool_destroy(struct page_pool *pool)
203{
c3f812ce 204}
1da4bbef 205
c3f812ce 206static inline void page_pool_use_xdp_mem(struct page_pool *pool,
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207 void (*disconnect)(void *),
208 struct xdp_mem_info *mem)
c3f812ce 209{
1da4bbef 210}
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211static inline void page_pool_release_page(struct page_pool *pool,
212 struct page *page)
213{
214}
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215
216static inline void page_pool_put_page_bulk(struct page_pool *pool, void **data,
217 int count)
218{
219}
c3f812ce 220#endif
1da4bbef 221
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222void page_pool_put_defragged_page(struct page_pool *pool, struct page *page,
223 unsigned int dma_sync_size,
224 bool allow_direct);
ff7d6b27 225
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226static inline void page_pool_fragment_page(struct page *page, long nr)
227{
228 atomic_long_set(&page->pp_frag_count, nr);
229}
230
231static inline long page_pool_defrag_page(struct page *page, long nr)
232{
233 long ret;
234
235 /* If nr == pp_frag_count then we have cleared all remaining
236 * references to the page. No need to actually overwrite it, instead
237 * we can leave this to be overwritten by the calling function.
238 *
239 * The main advantage to doing this is that an atomic_read is
240 * generally a much cheaper operation than an atomic update,
241 * especially when dealing with a page that may be partitioned
242 * into only 2 or 3 pieces.
243 */
244 if (atomic_long_read(&page->pp_frag_count) == nr)
245 return 0;
246
247 ret = atomic_long_sub_return(nr, &page->pp_frag_count);
248 WARN_ON(ret < 0);
249 return ret;
250}
251
252static inline bool page_pool_is_last_frag(struct page_pool *pool,
253 struct page *page)
254{
255 /* If fragments aren't enabled or count is 0 we were the last user */
256 return !(pool->p.flags & PP_FLAG_PAGE_FRAG) ||
257 (page_pool_defrag_page(page, 1) == 0);
258}
259
260static inline void page_pool_put_page(struct page_pool *pool,
261 struct page *page,
262 unsigned int dma_sync_size,
263 bool allow_direct)
ff7d6b27 264{
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265 /* When page_pool isn't compiled-in, net/core/xdp.c doesn't
266 * allow registering MEM_TYPE_PAGE_POOL, but shield linker.
267 */
268#ifdef CONFIG_PAGE_POOL
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269 if (!page_pool_is_last_frag(pool, page))
270 return;
271
272 page_pool_put_defragged_page(pool, page, dma_sync_size, allow_direct);
57d0a1c1 273#endif
ff7d6b27 274}
458de8a9 275
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276/* Same as above but will try to sync the entire area pool->max_len */
277static inline void page_pool_put_full_page(struct page_pool *pool,
278 struct page *page, bool allow_direct)
279{
280 page_pool_put_page(pool, page, -1, allow_direct);
281}
282
458de8a9 283/* Same as above but the caller must guarantee safe context. e.g NAPI */
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284static inline void page_pool_recycle_direct(struct page_pool *pool,
285 struct page *page)
286{
458de8a9 287 page_pool_put_full_page(pool, page, true);
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288}
289
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290#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \
291 (sizeof(dma_addr_t) > sizeof(unsigned long))
292
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293static inline dma_addr_t page_pool_get_dma_addr(struct page *page)
294{
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295 dma_addr_t ret = page->dma_addr;
296
297 if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
298 ret |= (dma_addr_t)page->dma_addr_upper << 16 << 16;
299
300 return ret;
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301}
302
303static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr)
304{
0e9d2a0a 305 page->dma_addr = addr;
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306 if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
307 page->dma_addr_upper = upper_32_bits(addr);
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308}
309
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310static inline bool is_page_pool_compiled_in(void)
311{
312#ifdef CONFIG_PAGE_POOL
313 return true;
314#else
315 return false;
316#endif
317}
318
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319static inline bool page_pool_put(struct page_pool *pool)
320{
321 return refcount_dec_and_test(&pool->user_cnt);
322}
323
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324/* Caller must provide appropriate safe context, e.g. NAPI. */
325void page_pool_update_nid(struct page_pool *pool, int new_nid);
326static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid)
327{
328 if (unlikely(pool->p.nid != new_nid))
329 page_pool_update_nid(pool, new_nid);
330}
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331
332static inline void page_pool_ring_lock(struct page_pool *pool)
333 __acquires(&pool->ring.producer_lock)
334{
335 if (in_serving_softirq())
336 spin_lock(&pool->ring.producer_lock);
337 else
338 spin_lock_bh(&pool->ring.producer_lock);
339}
340
341static inline void page_pool_ring_unlock(struct page_pool *pool)
342 __releases(&pool->ring.producer_lock)
343{
344 if (in_serving_softirq())
345 spin_unlock(&pool->ring.producer_lock);
346 else
347 spin_unlock_bh(&pool->ring.producer_lock);
348}
349
ff7d6b27 350#endif /* _NET_PAGE_POOL_H */