1 /* SPDX-License-Identifier: GPL-2.0 2 * 3 * page_pool.c 4 * Author: Jesper Dangaard Brouer <netoptimizer@brouer.com> 5 * Copyright (C) 2016 Red Hat, Inc. 6 */ 7 8 #include <linux/types.h> 9 #include <linux/kernel.h> 10 #include <linux/slab.h> 11 #include <linux/device.h> 12 13 #include <net/page_pool.h> 14 #include <net/xdp.h> 15 16 #include <linux/dma-direction.h> 17 #include <linux/dma-mapping.h> 18 #include <linux/page-flags.h> 19 #include <linux/mm.h> /* for __put_page() */ 20 #include <linux/poison.h> 21 22 #include <trace/events/page_pool.h> 23 24 #define DEFER_TIME (msecs_to_jiffies(1000)) 25 #define DEFER_WARN_INTERVAL (60 * HZ) 26 27 #define BIAS_MAX LONG_MAX 28 29 static int page_pool_init(struct page_pool *pool, 30 const struct page_pool_params *params) 31 { 32 unsigned int ring_qsize = 1024; /* Default */ 33 34 memcpy(&pool->p, params, sizeof(pool->p)); 35 36 /* Validate only known flags were used */ 37 if (pool->p.flags & ~(PP_FLAG_ALL)) 38 return -EINVAL; 39 40 if (pool->p.pool_size) 41 ring_qsize = pool->p.pool_size; 42 43 /* Sanity limit mem that can be pinned down */ 44 if (ring_qsize > 32768) 45 return -E2BIG; 46 47 /* DMA direction is either DMA_FROM_DEVICE or DMA_BIDIRECTIONAL. 48 * DMA_BIDIRECTIONAL is for allowing page used for DMA sending, 49 * which is the XDP_TX use-case. 50 */ 51 if (pool->p.flags & PP_FLAG_DMA_MAP) { 52 /* DMA-mapping is not supported on 32-bit systems with 53 * 64-bit DMA mapping. 54 */ 55 if (sizeof(dma_addr_t) > sizeof(unsigned long)) 56 return -EOPNOTSUPP; 57 58 if ((pool->p.dma_dir != DMA_FROM_DEVICE) && 59 (pool->p.dma_dir != DMA_BIDIRECTIONAL)) 60 return -EINVAL; 61 } 62 63 if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) { 64 /* In order to request DMA-sync-for-device the page 65 * needs to be mapped 66 */ 67 if (!(pool->p.flags & PP_FLAG_DMA_MAP)) 68 return -EINVAL; 69 70 if (!pool->p.max_len) 71 return -EINVAL; 72 73 /* pool->p.offset has to be set according to the address 74 * offset used by the DMA engine to start copying rx data 75 */ 76 } 77 78 if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0) 79 return -ENOMEM; 80 81 atomic_set(&pool->pages_state_release_cnt, 0); 82 83 /* Driver calling page_pool_create() also call page_pool_destroy() */ 84 refcount_set(&pool->user_cnt, 1); 85 86 if (pool->p.flags & PP_FLAG_DMA_MAP) 87 get_device(pool->p.dev); 88 89 return 0; 90 } 91 92 struct page_pool *page_pool_create(const struct page_pool_params *params) 93 { 94 struct page_pool *pool; 95 int err; 96 97 pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, params->nid); 98 if (!pool) 99 return ERR_PTR(-ENOMEM); 100 101 err = page_pool_init(pool, params); 102 if (err < 0) { 103 pr_warn("%s() gave up with errno %d\n", __func__, err); 104 kfree(pool); 105 return ERR_PTR(err); 106 } 107 108 return pool; 109 } 110 EXPORT_SYMBOL(page_pool_create); 111 112 static void page_pool_return_page(struct page_pool *pool, struct page *page); 113 114 noinline 115 static struct page *page_pool_refill_alloc_cache(struct page_pool *pool) 116 { 117 struct ptr_ring *r = &pool->ring; 118 struct page *page; 119 int pref_nid; /* preferred NUMA node */ 120 121 /* Quicker fallback, avoid locks when ring is empty */ 122 if (__ptr_ring_empty(r)) 123 return NULL; 124 125 /* Softirq guarantee CPU and thus NUMA node is stable. This, 126 * assumes CPU refilling driver RX-ring will also run RX-NAPI. 127 */ 128 #ifdef CONFIG_NUMA 129 pref_nid = (pool->p.nid == NUMA_NO_NODE) ? numa_mem_id() : pool->p.nid; 130 #else 131 /* Ignore pool->p.nid setting if !CONFIG_NUMA, helps compiler */ 132 pref_nid = numa_mem_id(); /* will be zero like page_to_nid() */ 133 #endif 134 135 /* Slower-path: Get pages from locked ring queue */ 136 spin_lock(&r->consumer_lock); 137 138 /* Refill alloc array, but only if NUMA match */ 139 do { 140 page = __ptr_ring_consume(r); 141 if (unlikely(!page)) 142 break; 143 144 if (likely(page_to_nid(page) == pref_nid)) { 145 pool->alloc.cache[pool->alloc.count++] = page; 146 } else { 147 /* NUMA mismatch; 148 * (1) release 1 page to page-allocator and 149 * (2) break out to fallthrough to alloc_pages_node. 150 * This limit stress on page buddy alloactor. 151 */ 152 page_pool_return_page(pool, page); 153 page = NULL; 154 break; 155 } 156 } while (pool->alloc.count < PP_ALLOC_CACHE_REFILL); 157 158 /* Return last page */ 159 if (likely(pool->alloc.count > 0)) 160 page = pool->alloc.cache[--pool->alloc.count]; 161 162 spin_unlock(&r->consumer_lock); 163 return page; 164 } 165 166 /* fast path */ 167 static struct page *__page_pool_get_cached(struct page_pool *pool) 168 { 169 struct page *page; 170 171 /* Caller MUST guarantee safe non-concurrent access, e.g. softirq */ 172 if (likely(pool->alloc.count)) { 173 /* Fast-path */ 174 page = pool->alloc.cache[--pool->alloc.count]; 175 } else { 176 page = page_pool_refill_alloc_cache(pool); 177 } 178 179 return page; 180 } 181 182 static void page_pool_dma_sync_for_device(struct page_pool *pool, 183 struct page *page, 184 unsigned int dma_sync_size) 185 { 186 dma_addr_t dma_addr = page_pool_get_dma_addr(page); 187 188 dma_sync_size = min(dma_sync_size, pool->p.max_len); 189 dma_sync_single_range_for_device(pool->p.dev, dma_addr, 190 pool->p.offset, dma_sync_size, 191 pool->p.dma_dir); 192 } 193 194 static bool page_pool_dma_map(struct page_pool *pool, struct page *page) 195 { 196 dma_addr_t dma; 197 198 /* Setup DMA mapping: use 'struct page' area for storing DMA-addr 199 * since dma_addr_t can be either 32 or 64 bits and does not always fit 200 * into page private data (i.e 32bit cpu with 64bit DMA caps) 201 * This mapping is kept for lifetime of page, until leaving pool. 202 */ 203 dma = dma_map_page_attrs(pool->p.dev, page, 0, 204 (PAGE_SIZE << pool->p.order), 205 pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC); 206 if (dma_mapping_error(pool->p.dev, dma)) 207 return false; 208 209 page_pool_set_dma_addr(page, dma); 210 211 if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) 212 page_pool_dma_sync_for_device(pool, page, pool->p.max_len); 213 214 return true; 215 } 216 217 static void page_pool_set_pp_info(struct page_pool *pool, 218 struct page *page) 219 { 220 page->pp = pool; 221 page->pp_magic |= PP_SIGNATURE; 222 } 223 224 static void page_pool_clear_pp_info(struct page *page) 225 { 226 page->pp_magic = 0; 227 page->pp = NULL; 228 } 229 230 static struct page *__page_pool_alloc_page_order(struct page_pool *pool, 231 gfp_t gfp) 232 { 233 struct page *page; 234 235 gfp |= __GFP_COMP; 236 page = alloc_pages_node(pool->p.nid, gfp, pool->p.order); 237 if (unlikely(!page)) 238 return NULL; 239 240 if ((pool->p.flags & PP_FLAG_DMA_MAP) && 241 unlikely(!page_pool_dma_map(pool, page))) { 242 put_page(page); 243 return NULL; 244 } 245 246 page_pool_set_pp_info(pool, page); 247 248 /* Track how many pages are held 'in-flight' */ 249 pool->pages_state_hold_cnt++; 250 trace_page_pool_state_hold(pool, page, pool->pages_state_hold_cnt); 251 return page; 252 } 253 254 /* slow path */ 255 noinline 256 static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool, 257 gfp_t gfp) 258 { 259 const int bulk = PP_ALLOC_CACHE_REFILL; 260 unsigned int pp_flags = pool->p.flags; 261 unsigned int pp_order = pool->p.order; 262 struct page *page; 263 int i, nr_pages; 264 265 /* Don't support bulk alloc for high-order pages */ 266 if (unlikely(pp_order)) 267 return __page_pool_alloc_page_order(pool, gfp); 268 269 /* Unnecessary as alloc cache is empty, but guarantees zero count */ 270 if (unlikely(pool->alloc.count > 0)) 271 return pool->alloc.cache[--pool->alloc.count]; 272 273 /* Mark empty alloc.cache slots "empty" for alloc_pages_bulk_array */ 274 memset(&pool->alloc.cache, 0, sizeof(void *) * bulk); 275 276 nr_pages = alloc_pages_bulk_array(gfp, bulk, pool->alloc.cache); 277 if (unlikely(!nr_pages)) 278 return NULL; 279 280 /* Pages have been filled into alloc.cache array, but count is zero and 281 * page element have not been (possibly) DMA mapped. 282 */ 283 for (i = 0; i < nr_pages; i++) { 284 page = pool->alloc.cache[i]; 285 if ((pp_flags & PP_FLAG_DMA_MAP) && 286 unlikely(!page_pool_dma_map(pool, page))) { 287 put_page(page); 288 continue; 289 } 290 291 page_pool_set_pp_info(pool, page); 292 pool->alloc.cache[pool->alloc.count++] = page; 293 /* Track how many pages are held 'in-flight' */ 294 pool->pages_state_hold_cnt++; 295 trace_page_pool_state_hold(pool, page, 296 pool->pages_state_hold_cnt); 297 } 298 299 /* Return last page */ 300 if (likely(pool->alloc.count > 0)) 301 page = pool->alloc.cache[--pool->alloc.count]; 302 else 303 page = NULL; 304 305 /* When page just alloc'ed is should/must have refcnt 1. */ 306 return page; 307 } 308 309 /* For using page_pool replace: alloc_pages() API calls, but provide 310 * synchronization guarantee for allocation side. 311 */ 312 struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp) 313 { 314 struct page *page; 315 316 /* Fast-path: Get a page from cache */ 317 page = __page_pool_get_cached(pool); 318 if (page) 319 return page; 320 321 /* Slow-path: cache empty, do real allocation */ 322 page = __page_pool_alloc_pages_slow(pool, gfp); 323 return page; 324 } 325 EXPORT_SYMBOL(page_pool_alloc_pages); 326 327 /* Calculate distance between two u32 values, valid if distance is below 2^(31) 328 * https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution 329 */ 330 #define _distance(a, b) (s32)((a) - (b)) 331 332 static s32 page_pool_inflight(struct page_pool *pool) 333 { 334 u32 release_cnt = atomic_read(&pool->pages_state_release_cnt); 335 u32 hold_cnt = READ_ONCE(pool->pages_state_hold_cnt); 336 s32 inflight; 337 338 inflight = _distance(hold_cnt, release_cnt); 339 340 trace_page_pool_release(pool, inflight, hold_cnt, release_cnt); 341 WARN(inflight < 0, "Negative(%d) inflight packet-pages", inflight); 342 343 return inflight; 344 } 345 346 /* Disconnects a page (from a page_pool). API users can have a need 347 * to disconnect a page (from a page_pool), to allow it to be used as 348 * a regular page (that will eventually be returned to the normal 349 * page-allocator via put_page). 350 */ 351 void page_pool_release_page(struct page_pool *pool, struct page *page) 352 { 353 dma_addr_t dma; 354 int count; 355 356 if (!(pool->p.flags & PP_FLAG_DMA_MAP)) 357 /* Always account for inflight pages, even if we didn't 358 * map them 359 */ 360 goto skip_dma_unmap; 361 362 dma = page_pool_get_dma_addr(page); 363 364 /* When page is unmapped, it cannot be returned to our pool */ 365 dma_unmap_page_attrs(pool->p.dev, dma, 366 PAGE_SIZE << pool->p.order, pool->p.dma_dir, 367 DMA_ATTR_SKIP_CPU_SYNC); 368 page_pool_set_dma_addr(page, 0); 369 skip_dma_unmap: 370 page_pool_clear_pp_info(page); 371 372 /* This may be the last page returned, releasing the pool, so 373 * it is not safe to reference pool afterwards. 374 */ 375 count = atomic_inc_return_relaxed(&pool->pages_state_release_cnt); 376 trace_page_pool_state_release(pool, page, count); 377 } 378 EXPORT_SYMBOL(page_pool_release_page); 379 380 /* Return a page to the page allocator, cleaning up our state */ 381 static void page_pool_return_page(struct page_pool *pool, struct page *page) 382 { 383 page_pool_release_page(pool, page); 384 385 put_page(page); 386 /* An optimization would be to call __free_pages(page, pool->p.order) 387 * knowing page is not part of page-cache (thus avoiding a 388 * __page_cache_release() call). 389 */ 390 } 391 392 static bool page_pool_recycle_in_ring(struct page_pool *pool, struct page *page) 393 { 394 int ret; 395 /* BH protection not needed if current is serving softirq */ 396 if (in_serving_softirq()) 397 ret = ptr_ring_produce(&pool->ring, page); 398 else 399 ret = ptr_ring_produce_bh(&pool->ring, page); 400 401 return (ret == 0) ? true : false; 402 } 403 404 /* Only allow direct recycling in special circumstances, into the 405 * alloc side cache. E.g. during RX-NAPI processing for XDP_DROP use-case. 406 * 407 * Caller must provide appropriate safe context. 408 */ 409 static bool page_pool_recycle_in_cache(struct page *page, 410 struct page_pool *pool) 411 { 412 if (unlikely(pool->alloc.count == PP_ALLOC_CACHE_SIZE)) 413 return false; 414 415 /* Caller MUST have verified/know (page_ref_count(page) == 1) */ 416 pool->alloc.cache[pool->alloc.count++] = page; 417 return true; 418 } 419 420 /* If the page refcnt == 1, this will try to recycle the page. 421 * if PP_FLAG_DMA_SYNC_DEV is set, we'll try to sync the DMA area for 422 * the configured size min(dma_sync_size, pool->max_len). 423 * If the page refcnt != 1, then the page will be returned to memory 424 * subsystem. 425 */ 426 static __always_inline struct page * 427 __page_pool_put_page(struct page_pool *pool, struct page *page, 428 unsigned int dma_sync_size, bool allow_direct) 429 { 430 /* It is not the last user for the page frag case */ 431 if (pool->p.flags & PP_FLAG_PAGE_FRAG && 432 page_pool_atomic_sub_frag_count_return(page, 1)) 433 return NULL; 434 435 /* This allocator is optimized for the XDP mode that uses 436 * one-frame-per-page, but have fallbacks that act like the 437 * regular page allocator APIs. 438 * 439 * refcnt == 1 means page_pool owns page, and can recycle it. 440 * 441 * page is NOT reusable when allocated when system is under 442 * some pressure. (page_is_pfmemalloc) 443 */ 444 if (likely(page_ref_count(page) == 1 && !page_is_pfmemalloc(page))) { 445 /* Read barrier done in page_ref_count / READ_ONCE */ 446 447 if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) 448 page_pool_dma_sync_for_device(pool, page, 449 dma_sync_size); 450 451 if (allow_direct && in_serving_softirq() && 452 page_pool_recycle_in_cache(page, pool)) 453 return NULL; 454 455 /* Page found as candidate for recycling */ 456 return page; 457 } 458 /* Fallback/non-XDP mode: API user have elevated refcnt. 459 * 460 * Many drivers split up the page into fragments, and some 461 * want to keep doing this to save memory and do refcnt based 462 * recycling. Support this use case too, to ease drivers 463 * switching between XDP/non-XDP. 464 * 465 * In-case page_pool maintains the DMA mapping, API user must 466 * call page_pool_put_page once. In this elevated refcnt 467 * case, the DMA is unmapped/released, as driver is likely 468 * doing refcnt based recycle tricks, meaning another process 469 * will be invoking put_page. 470 */ 471 /* Do not replace this with page_pool_return_page() */ 472 page_pool_release_page(pool, page); 473 put_page(page); 474 475 return NULL; 476 } 477 478 void page_pool_put_page(struct page_pool *pool, struct page *page, 479 unsigned int dma_sync_size, bool allow_direct) 480 { 481 page = __page_pool_put_page(pool, page, dma_sync_size, allow_direct); 482 if (page && !page_pool_recycle_in_ring(pool, page)) { 483 /* Cache full, fallback to free pages */ 484 page_pool_return_page(pool, page); 485 } 486 } 487 EXPORT_SYMBOL(page_pool_put_page); 488 489 /* Caller must not use data area after call, as this function overwrites it */ 490 void page_pool_put_page_bulk(struct page_pool *pool, void **data, 491 int count) 492 { 493 int i, bulk_len = 0; 494 495 for (i = 0; i < count; i++) { 496 struct page *page = virt_to_head_page(data[i]); 497 498 page = __page_pool_put_page(pool, page, -1, false); 499 /* Approved for bulk recycling in ptr_ring cache */ 500 if (page) 501 data[bulk_len++] = page; 502 } 503 504 if (unlikely(!bulk_len)) 505 return; 506 507 /* Bulk producer into ptr_ring page_pool cache */ 508 page_pool_ring_lock(pool); 509 for (i = 0; i < bulk_len; i++) { 510 if (__ptr_ring_produce(&pool->ring, data[i])) 511 break; /* ring full */ 512 } 513 page_pool_ring_unlock(pool); 514 515 /* Hopefully all pages was return into ptr_ring */ 516 if (likely(i == bulk_len)) 517 return; 518 519 /* ptr_ring cache full, free remaining pages outside producer lock 520 * since put_page() with refcnt == 1 can be an expensive operation 521 */ 522 for (; i < bulk_len; i++) 523 page_pool_return_page(pool, data[i]); 524 } 525 EXPORT_SYMBOL(page_pool_put_page_bulk); 526 527 static struct page *page_pool_drain_frag(struct page_pool *pool, 528 struct page *page) 529 { 530 long drain_count = BIAS_MAX - pool->frag_users; 531 532 /* Some user is still using the page frag */ 533 if (likely(page_pool_atomic_sub_frag_count_return(page, 534 drain_count))) 535 return NULL; 536 537 if (page_ref_count(page) == 1 && !page_is_pfmemalloc(page)) { 538 if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) 539 page_pool_dma_sync_for_device(pool, page, -1); 540 541 return page; 542 } 543 544 page_pool_return_page(pool, page); 545 return NULL; 546 } 547 548 static void page_pool_free_frag(struct page_pool *pool) 549 { 550 long drain_count = BIAS_MAX - pool->frag_users; 551 struct page *page = pool->frag_page; 552 553 pool->frag_page = NULL; 554 555 if (!page || 556 page_pool_atomic_sub_frag_count_return(page, drain_count)) 557 return; 558 559 page_pool_return_page(pool, page); 560 } 561 562 struct page *page_pool_alloc_frag(struct page_pool *pool, 563 unsigned int *offset, 564 unsigned int size, gfp_t gfp) 565 { 566 unsigned int max_size = PAGE_SIZE << pool->p.order; 567 struct page *page = pool->frag_page; 568 569 if (WARN_ON(!(pool->p.flags & PP_FLAG_PAGE_FRAG) || 570 size > max_size)) 571 return NULL; 572 573 size = ALIGN(size, dma_get_cache_alignment()); 574 *offset = pool->frag_offset; 575 576 if (page && *offset + size > max_size) { 577 page = page_pool_drain_frag(pool, page); 578 if (page) 579 goto frag_reset; 580 } 581 582 if (!page) { 583 page = page_pool_alloc_pages(pool, gfp); 584 if (unlikely(!page)) { 585 pool->frag_page = NULL; 586 return NULL; 587 } 588 589 pool->frag_page = page; 590 591 frag_reset: 592 pool->frag_users = 1; 593 *offset = 0; 594 pool->frag_offset = size; 595 page_pool_set_frag_count(page, BIAS_MAX); 596 return page; 597 } 598 599 pool->frag_users++; 600 pool->frag_offset = *offset + size; 601 return page; 602 } 603 EXPORT_SYMBOL(page_pool_alloc_frag); 604 605 static void page_pool_empty_ring(struct page_pool *pool) 606 { 607 struct page *page; 608 609 /* Empty recycle ring */ 610 while ((page = ptr_ring_consume_bh(&pool->ring))) { 611 /* Verify the refcnt invariant of cached pages */ 612 if (!(page_ref_count(page) == 1)) 613 pr_crit("%s() page_pool refcnt %d violation\n", 614 __func__, page_ref_count(page)); 615 616 page_pool_return_page(pool, page); 617 } 618 } 619 620 static void page_pool_free(struct page_pool *pool) 621 { 622 if (pool->disconnect) 623 pool->disconnect(pool); 624 625 ptr_ring_cleanup(&pool->ring, NULL); 626 627 if (pool->p.flags & PP_FLAG_DMA_MAP) 628 put_device(pool->p.dev); 629 630 kfree(pool); 631 } 632 633 static void page_pool_empty_alloc_cache_once(struct page_pool *pool) 634 { 635 struct page *page; 636 637 if (pool->destroy_cnt) 638 return; 639 640 /* Empty alloc cache, assume caller made sure this is 641 * no-longer in use, and page_pool_alloc_pages() cannot be 642 * call concurrently. 643 */ 644 while (pool->alloc.count) { 645 page = pool->alloc.cache[--pool->alloc.count]; 646 page_pool_return_page(pool, page); 647 } 648 } 649 650 static void page_pool_scrub(struct page_pool *pool) 651 { 652 page_pool_empty_alloc_cache_once(pool); 653 pool->destroy_cnt++; 654 655 /* No more consumers should exist, but producers could still 656 * be in-flight. 657 */ 658 page_pool_empty_ring(pool); 659 } 660 661 static int page_pool_release(struct page_pool *pool) 662 { 663 int inflight; 664 665 page_pool_scrub(pool); 666 inflight = page_pool_inflight(pool); 667 if (!inflight) 668 page_pool_free(pool); 669 670 return inflight; 671 } 672 673 static void page_pool_release_retry(struct work_struct *wq) 674 { 675 struct delayed_work *dwq = to_delayed_work(wq); 676 struct page_pool *pool = container_of(dwq, typeof(*pool), release_dw); 677 int inflight; 678 679 inflight = page_pool_release(pool); 680 if (!inflight) 681 return; 682 683 /* Periodic warning */ 684 if (time_after_eq(jiffies, pool->defer_warn)) { 685 int sec = (s32)((u32)jiffies - (u32)pool->defer_start) / HZ; 686 687 pr_warn("%s() stalled pool shutdown %d inflight %d sec\n", 688 __func__, inflight, sec); 689 pool->defer_warn = jiffies + DEFER_WARN_INTERVAL; 690 } 691 692 /* Still not ready to be disconnected, retry later */ 693 schedule_delayed_work(&pool->release_dw, DEFER_TIME); 694 } 695 696 void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *)) 697 { 698 refcount_inc(&pool->user_cnt); 699 pool->disconnect = disconnect; 700 } 701 702 void page_pool_destroy(struct page_pool *pool) 703 { 704 if (!pool) 705 return; 706 707 if (!page_pool_put(pool)) 708 return; 709 710 page_pool_free_frag(pool); 711 712 if (!page_pool_release(pool)) 713 return; 714 715 pool->defer_start = jiffies; 716 pool->defer_warn = jiffies + DEFER_WARN_INTERVAL; 717 718 INIT_DELAYED_WORK(&pool->release_dw, page_pool_release_retry); 719 schedule_delayed_work(&pool->release_dw, DEFER_TIME); 720 } 721 EXPORT_SYMBOL(page_pool_destroy); 722 723 /* Caller must provide appropriate safe context, e.g. NAPI. */ 724 void page_pool_update_nid(struct page_pool *pool, int new_nid) 725 { 726 struct page *page; 727 728 trace_page_pool_update_nid(pool, new_nid); 729 pool->p.nid = new_nid; 730 731 /* Flush pool alloc cache, as refill will check NUMA node */ 732 while (pool->alloc.count) { 733 page = pool->alloc.cache[--pool->alloc.count]; 734 page_pool_return_page(pool, page); 735 } 736 } 737 EXPORT_SYMBOL(page_pool_update_nid); 738 739 bool page_pool_return_skb_page(struct page *page) 740 { 741 struct page_pool *pp; 742 743 page = compound_head(page); 744 745 /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation 746 * in order to preserve any existing bits, such as bit 0 for the 747 * head page of compound page and bit 1 for pfmemalloc page, so 748 * mask those bits for freeing side when doing below checking, 749 * and page_is_pfmemalloc() is checked in __page_pool_put_page() 750 * to avoid recycling the pfmemalloc page. 751 */ 752 if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE)) 753 return false; 754 755 pp = page->pp; 756 757 /* Driver set this to memory recycling info. Reset it on recycle. 758 * This will *not* work for NIC using a split-page memory model. 759 * The page will be returned to the pool here regardless of the 760 * 'flipped' fragment being in use or not. 761 */ 762 page_pool_put_full_page(pp, page, false); 763 764 return true; 765 } 766 EXPORT_SYMBOL(page_pool_return_skb_page); 767