diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /net/core/page_pool.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/core/page_pool.c')
-rw-r--r-- | net/core/page_pool.c | 943 |
1 files changed, 943 insertions, 0 deletions
diff --git a/net/core/page_pool.c b/net/core/page_pool.c new file mode 100644 index 0000000000..31f923e7b5 --- /dev/null +++ b/net/core/page_pool.c @@ -0,0 +1,943 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * page_pool.c + * Author: Jesper Dangaard Brouer <netoptimizer@brouer.com> + * Copyright (C) 2016 Red Hat, Inc. + */ + +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/device.h> + +#include <net/page_pool/helpers.h> +#include <net/xdp.h> + +#include <linux/dma-direction.h> +#include <linux/dma-mapping.h> +#include <linux/page-flags.h> +#include <linux/mm.h> /* for put_page() */ +#include <linux/poison.h> +#include <linux/ethtool.h> +#include <linux/netdevice.h> + +#include <trace/events/page_pool.h> + +#define DEFER_TIME (msecs_to_jiffies(1000)) +#define DEFER_WARN_INTERVAL (60 * HZ) + +#define BIAS_MAX LONG_MAX + +#ifdef CONFIG_PAGE_POOL_STATS +/* alloc_stat_inc is intended to be used in softirq context */ +#define alloc_stat_inc(pool, __stat) (pool->alloc_stats.__stat++) +/* recycle_stat_inc is safe to use when preemption is possible. */ +#define recycle_stat_inc(pool, __stat) \ + do { \ + struct page_pool_recycle_stats __percpu *s = pool->recycle_stats; \ + this_cpu_inc(s->__stat); \ + } while (0) + +#define recycle_stat_add(pool, __stat, val) \ + do { \ + struct page_pool_recycle_stats __percpu *s = pool->recycle_stats; \ + this_cpu_add(s->__stat, val); \ + } while (0) + +static const char pp_stats[][ETH_GSTRING_LEN] = { + "rx_pp_alloc_fast", + "rx_pp_alloc_slow", + "rx_pp_alloc_slow_ho", + "rx_pp_alloc_empty", + "rx_pp_alloc_refill", + "rx_pp_alloc_waive", + "rx_pp_recycle_cached", + "rx_pp_recycle_cache_full", + "rx_pp_recycle_ring", + "rx_pp_recycle_ring_full", + "rx_pp_recycle_released_ref", +}; + +/** + * page_pool_get_stats() - fetch page pool stats + * @pool: pool from which page was allocated + * @stats: struct page_pool_stats to fill in + * + * Retrieve statistics about the page_pool. This API is only available + * if the kernel has been configured with ``CONFIG_PAGE_POOL_STATS=y``. + * A pointer to a caller allocated struct page_pool_stats structure + * is passed to this API which is filled in. The caller can then report + * those stats to the user (perhaps via ethtool, debugfs, etc.). + */ +bool page_pool_get_stats(struct page_pool *pool, + struct page_pool_stats *stats) +{ + int cpu = 0; + + if (!stats) + return false; + + /* The caller is responsible to initialize stats. */ + stats->alloc_stats.fast += pool->alloc_stats.fast; + stats->alloc_stats.slow += pool->alloc_stats.slow; + stats->alloc_stats.slow_high_order += pool->alloc_stats.slow_high_order; + stats->alloc_stats.empty += pool->alloc_stats.empty; + stats->alloc_stats.refill += pool->alloc_stats.refill; + stats->alloc_stats.waive += pool->alloc_stats.waive; + + for_each_possible_cpu(cpu) { + const struct page_pool_recycle_stats *pcpu = + per_cpu_ptr(pool->recycle_stats, cpu); + + stats->recycle_stats.cached += pcpu->cached; + stats->recycle_stats.cache_full += pcpu->cache_full; + stats->recycle_stats.ring += pcpu->ring; + stats->recycle_stats.ring_full += pcpu->ring_full; + stats->recycle_stats.released_refcnt += pcpu->released_refcnt; + } + + return true; +} +EXPORT_SYMBOL(page_pool_get_stats); + +u8 *page_pool_ethtool_stats_get_strings(u8 *data) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(pp_stats); i++) { + memcpy(data, pp_stats[i], ETH_GSTRING_LEN); + data += ETH_GSTRING_LEN; + } + + return data; +} +EXPORT_SYMBOL(page_pool_ethtool_stats_get_strings); + +int page_pool_ethtool_stats_get_count(void) +{ + return ARRAY_SIZE(pp_stats); +} +EXPORT_SYMBOL(page_pool_ethtool_stats_get_count); + +u64 *page_pool_ethtool_stats_get(u64 *data, void *stats) +{ + struct page_pool_stats *pool_stats = stats; + + *data++ = pool_stats->alloc_stats.fast; + *data++ = pool_stats->alloc_stats.slow; + *data++ = pool_stats->alloc_stats.slow_high_order; + *data++ = pool_stats->alloc_stats.empty; + *data++ = pool_stats->alloc_stats.refill; + *data++ = pool_stats->alloc_stats.waive; + *data++ = pool_stats->recycle_stats.cached; + *data++ = pool_stats->recycle_stats.cache_full; + *data++ = pool_stats->recycle_stats.ring; + *data++ = pool_stats->recycle_stats.ring_full; + *data++ = pool_stats->recycle_stats.released_refcnt; + + return data; +} +EXPORT_SYMBOL(page_pool_ethtool_stats_get); + +#else +#define alloc_stat_inc(pool, __stat) +#define recycle_stat_inc(pool, __stat) +#define recycle_stat_add(pool, __stat, val) +#endif + +static bool page_pool_producer_lock(struct page_pool *pool) + __acquires(&pool->ring.producer_lock) +{ + bool in_softirq = in_softirq(); + + if (in_softirq) + spin_lock(&pool->ring.producer_lock); + else + spin_lock_bh(&pool->ring.producer_lock); + + return in_softirq; +} + +static void page_pool_producer_unlock(struct page_pool *pool, + bool in_softirq) + __releases(&pool->ring.producer_lock) +{ + if (in_softirq) + spin_unlock(&pool->ring.producer_lock); + else + spin_unlock_bh(&pool->ring.producer_lock); +} + +static int page_pool_init(struct page_pool *pool, + const struct page_pool_params *params) +{ + unsigned int ring_qsize = 1024; /* Default */ + + memcpy(&pool->p, params, sizeof(pool->p)); + + /* Validate only known flags were used */ + if (pool->p.flags & ~(PP_FLAG_ALL)) + return -EINVAL; + + if (pool->p.pool_size) + ring_qsize = pool->p.pool_size; + + /* Sanity limit mem that can be pinned down */ + if (ring_qsize > 32768) + return -E2BIG; + + /* DMA direction is either DMA_FROM_DEVICE or DMA_BIDIRECTIONAL. + * DMA_BIDIRECTIONAL is for allowing page used for DMA sending, + * which is the XDP_TX use-case. + */ + if (pool->p.flags & PP_FLAG_DMA_MAP) { + if ((pool->p.dma_dir != DMA_FROM_DEVICE) && + (pool->p.dma_dir != DMA_BIDIRECTIONAL)) + return -EINVAL; + } + + if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) { + /* In order to request DMA-sync-for-device the page + * needs to be mapped + */ + if (!(pool->p.flags & PP_FLAG_DMA_MAP)) + return -EINVAL; + + if (!pool->p.max_len) + return -EINVAL; + + /* pool->p.offset has to be set according to the address + * offset used by the DMA engine to start copying rx data + */ + } + + if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT && + pool->p.flags & PP_FLAG_PAGE_FRAG) + return -EINVAL; + +#ifdef CONFIG_PAGE_POOL_STATS + pool->recycle_stats = alloc_percpu(struct page_pool_recycle_stats); + if (!pool->recycle_stats) + return -ENOMEM; +#endif + + if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0) { +#ifdef CONFIG_PAGE_POOL_STATS + free_percpu(pool->recycle_stats); +#endif + return -ENOMEM; + } + + atomic_set(&pool->pages_state_release_cnt, 0); + + /* Driver calling page_pool_create() also call page_pool_destroy() */ + refcount_set(&pool->user_cnt, 1); + + if (pool->p.flags & PP_FLAG_DMA_MAP) + get_device(pool->p.dev); + + return 0; +} + +/** + * page_pool_create() - create a page pool. + * @params: parameters, see struct page_pool_params + */ +struct page_pool *page_pool_create(const struct page_pool_params *params) +{ + struct page_pool *pool; + int err; + + pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, params->nid); + if (!pool) + return ERR_PTR(-ENOMEM); + + err = page_pool_init(pool, params); + if (err < 0) { + pr_warn("%s() gave up with errno %d\n", __func__, err); + kfree(pool); + return ERR_PTR(err); + } + + return pool; +} +EXPORT_SYMBOL(page_pool_create); + +static void page_pool_return_page(struct page_pool *pool, struct page *page); + +noinline +static struct page *page_pool_refill_alloc_cache(struct page_pool *pool) +{ + struct ptr_ring *r = &pool->ring; + struct page *page; + int pref_nid; /* preferred NUMA node */ + + /* Quicker fallback, avoid locks when ring is empty */ + if (__ptr_ring_empty(r)) { + alloc_stat_inc(pool, empty); + return NULL; + } + + /* Softirq guarantee CPU and thus NUMA node is stable. This, + * assumes CPU refilling driver RX-ring will also run RX-NAPI. + */ +#ifdef CONFIG_NUMA + pref_nid = (pool->p.nid == NUMA_NO_NODE) ? numa_mem_id() : pool->p.nid; +#else + /* Ignore pool->p.nid setting if !CONFIG_NUMA, helps compiler */ + pref_nid = numa_mem_id(); /* will be zero like page_to_nid() */ +#endif + + /* Refill alloc array, but only if NUMA match */ + do { + page = __ptr_ring_consume(r); + if (unlikely(!page)) + break; + + if (likely(page_to_nid(page) == pref_nid)) { + pool->alloc.cache[pool->alloc.count++] = page; + } else { + /* NUMA mismatch; + * (1) release 1 page to page-allocator and + * (2) break out to fallthrough to alloc_pages_node. + * This limit stress on page buddy alloactor. + */ + page_pool_return_page(pool, page); + alloc_stat_inc(pool, waive); + page = NULL; + break; + } + } while (pool->alloc.count < PP_ALLOC_CACHE_REFILL); + + /* Return last page */ + if (likely(pool->alloc.count > 0)) { + page = pool->alloc.cache[--pool->alloc.count]; + alloc_stat_inc(pool, refill); + } + + return page; +} + +/* fast path */ +static struct page *__page_pool_get_cached(struct page_pool *pool) +{ + struct page *page; + + /* Caller MUST guarantee safe non-concurrent access, e.g. softirq */ + if (likely(pool->alloc.count)) { + /* Fast-path */ + page = pool->alloc.cache[--pool->alloc.count]; + alloc_stat_inc(pool, fast); + } else { + page = page_pool_refill_alloc_cache(pool); + } + + return page; +} + +static void page_pool_dma_sync_for_device(struct page_pool *pool, + struct page *page, + unsigned int dma_sync_size) +{ + dma_addr_t dma_addr = page_pool_get_dma_addr(page); + + dma_sync_size = min(dma_sync_size, pool->p.max_len); + dma_sync_single_range_for_device(pool->p.dev, dma_addr, + pool->p.offset, dma_sync_size, + pool->p.dma_dir); +} + +static bool page_pool_dma_map(struct page_pool *pool, struct page *page) +{ + dma_addr_t dma; + + /* Setup DMA mapping: use 'struct page' area for storing DMA-addr + * since dma_addr_t can be either 32 or 64 bits and does not always fit + * into page private data (i.e 32bit cpu with 64bit DMA caps) + * This mapping is kept for lifetime of page, until leaving pool. + */ + dma = dma_map_page_attrs(pool->p.dev, page, 0, + (PAGE_SIZE << pool->p.order), + pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC | + DMA_ATTR_WEAK_ORDERING); + if (dma_mapping_error(pool->p.dev, dma)) + return false; + + page_pool_set_dma_addr(page, dma); + + if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) + page_pool_dma_sync_for_device(pool, page, pool->p.max_len); + + return true; +} + +static void page_pool_set_pp_info(struct page_pool *pool, + struct page *page) +{ + page->pp = pool; + page->pp_magic |= PP_SIGNATURE; + if (pool->p.init_callback) + pool->p.init_callback(page, pool->p.init_arg); +} + +static void page_pool_clear_pp_info(struct page *page) +{ + page->pp_magic = 0; + page->pp = NULL; +} + +static struct page *__page_pool_alloc_page_order(struct page_pool *pool, + gfp_t gfp) +{ + struct page *page; + + gfp |= __GFP_COMP; + page = alloc_pages_node(pool->p.nid, gfp, pool->p.order); + if (unlikely(!page)) + return NULL; + + if ((pool->p.flags & PP_FLAG_DMA_MAP) && + unlikely(!page_pool_dma_map(pool, page))) { + put_page(page); + return NULL; + } + + alloc_stat_inc(pool, slow_high_order); + page_pool_set_pp_info(pool, page); + + /* Track how many pages are held 'in-flight' */ + pool->pages_state_hold_cnt++; + trace_page_pool_state_hold(pool, page, pool->pages_state_hold_cnt); + return page; +} + +/* slow path */ +noinline +static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool, + gfp_t gfp) +{ + const int bulk = PP_ALLOC_CACHE_REFILL; + unsigned int pp_flags = pool->p.flags; + unsigned int pp_order = pool->p.order; + struct page *page; + int i, nr_pages; + + /* Don't support bulk alloc for high-order pages */ + if (unlikely(pp_order)) + return __page_pool_alloc_page_order(pool, gfp); + + /* Unnecessary as alloc cache is empty, but guarantees zero count */ + if (unlikely(pool->alloc.count > 0)) + return pool->alloc.cache[--pool->alloc.count]; + + /* Mark empty alloc.cache slots "empty" for alloc_pages_bulk_array */ + memset(&pool->alloc.cache, 0, sizeof(void *) * bulk); + + nr_pages = alloc_pages_bulk_array_node(gfp, pool->p.nid, bulk, + pool->alloc.cache); + if (unlikely(!nr_pages)) + return NULL; + + /* Pages have been filled into alloc.cache array, but count is zero and + * page element have not been (possibly) DMA mapped. + */ + for (i = 0; i < nr_pages; i++) { + page = pool->alloc.cache[i]; + if ((pp_flags & PP_FLAG_DMA_MAP) && + unlikely(!page_pool_dma_map(pool, page))) { + put_page(page); + continue; + } + + page_pool_set_pp_info(pool, page); + pool->alloc.cache[pool->alloc.count++] = page; + /* Track how many pages are held 'in-flight' */ + pool->pages_state_hold_cnt++; + trace_page_pool_state_hold(pool, page, + pool->pages_state_hold_cnt); + } + + /* Return last page */ + if (likely(pool->alloc.count > 0)) { + page = pool->alloc.cache[--pool->alloc.count]; + alloc_stat_inc(pool, slow); + } else { + page = NULL; + } + + /* When page just alloc'ed is should/must have refcnt 1. */ + return page; +} + +/* For using page_pool replace: alloc_pages() API calls, but provide + * synchronization guarantee for allocation side. + */ +struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp) +{ + struct page *page; + + /* Fast-path: Get a page from cache */ + page = __page_pool_get_cached(pool); + if (page) + return page; + + /* Slow-path: cache empty, do real allocation */ + page = __page_pool_alloc_pages_slow(pool, gfp); + return page; +} +EXPORT_SYMBOL(page_pool_alloc_pages); + +/* Calculate distance between two u32 values, valid if distance is below 2^(31) + * https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution + */ +#define _distance(a, b) (s32)((a) - (b)) + +static s32 page_pool_inflight(struct page_pool *pool) +{ + u32 release_cnt = atomic_read(&pool->pages_state_release_cnt); + u32 hold_cnt = READ_ONCE(pool->pages_state_hold_cnt); + s32 inflight; + + inflight = _distance(hold_cnt, release_cnt); + + trace_page_pool_release(pool, inflight, hold_cnt, release_cnt); + WARN(inflight < 0, "Negative(%d) inflight packet-pages", inflight); + + return inflight; +} + +/* Disconnects a page (from a page_pool). API users can have a need + * to disconnect a page (from a page_pool), to allow it to be used as + * a regular page (that will eventually be returned to the normal + * page-allocator via put_page). + */ +static void page_pool_return_page(struct page_pool *pool, struct page *page) +{ + dma_addr_t dma; + int count; + + if (!(pool->p.flags & PP_FLAG_DMA_MAP)) + /* Always account for inflight pages, even if we didn't + * map them + */ + goto skip_dma_unmap; + + dma = page_pool_get_dma_addr(page); + + /* When page is unmapped, it cannot be returned to our pool */ + dma_unmap_page_attrs(pool->p.dev, dma, + PAGE_SIZE << pool->p.order, pool->p.dma_dir, + DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING); + page_pool_set_dma_addr(page, 0); +skip_dma_unmap: + page_pool_clear_pp_info(page); + + /* This may be the last page returned, releasing the pool, so + * it is not safe to reference pool afterwards. + */ + count = atomic_inc_return_relaxed(&pool->pages_state_release_cnt); + trace_page_pool_state_release(pool, page, count); + + put_page(page); + /* An optimization would be to call __free_pages(page, pool->p.order) + * knowing page is not part of page-cache (thus avoiding a + * __page_cache_release() call). + */ +} + +static bool page_pool_recycle_in_ring(struct page_pool *pool, struct page *page) +{ + int ret; + /* BH protection not needed if current is softirq */ + if (in_softirq()) + ret = ptr_ring_produce(&pool->ring, page); + else + ret = ptr_ring_produce_bh(&pool->ring, page); + + if (!ret) { + recycle_stat_inc(pool, ring); + return true; + } + + return false; +} + +/* Only allow direct recycling in special circumstances, into the + * alloc side cache. E.g. during RX-NAPI processing for XDP_DROP use-case. + * + * Caller must provide appropriate safe context. + */ +static bool page_pool_recycle_in_cache(struct page *page, + struct page_pool *pool) +{ + if (unlikely(pool->alloc.count == PP_ALLOC_CACHE_SIZE)) { + recycle_stat_inc(pool, cache_full); + return false; + } + + /* Caller MUST have verified/know (page_ref_count(page) == 1) */ + pool->alloc.cache[pool->alloc.count++] = page; + recycle_stat_inc(pool, cached); + return true; +} + +/* If the page refcnt == 1, this will try to recycle the page. + * if PP_FLAG_DMA_SYNC_DEV is set, we'll try to sync the DMA area for + * the configured size min(dma_sync_size, pool->max_len). + * If the page refcnt != 1, then the page will be returned to memory + * subsystem. + */ +static __always_inline struct page * +__page_pool_put_page(struct page_pool *pool, struct page *page, + unsigned int dma_sync_size, bool allow_direct) +{ + lockdep_assert_no_hardirq(); + + /* This allocator is optimized for the XDP mode that uses + * one-frame-per-page, but have fallbacks that act like the + * regular page allocator APIs. + * + * refcnt == 1 means page_pool owns page, and can recycle it. + * + * page is NOT reusable when allocated when system is under + * some pressure. (page_is_pfmemalloc) + */ + if (likely(page_ref_count(page) == 1 && !page_is_pfmemalloc(page))) { + /* Read barrier done in page_ref_count / READ_ONCE */ + + if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) + page_pool_dma_sync_for_device(pool, page, + dma_sync_size); + + if (allow_direct && in_softirq() && + page_pool_recycle_in_cache(page, pool)) + return NULL; + + /* Page found as candidate for recycling */ + return page; + } + /* Fallback/non-XDP mode: API user have elevated refcnt. + * + * Many drivers split up the page into fragments, and some + * want to keep doing this to save memory and do refcnt based + * recycling. Support this use case too, to ease drivers + * switching between XDP/non-XDP. + * + * In-case page_pool maintains the DMA mapping, API user must + * call page_pool_put_page once. In this elevated refcnt + * case, the DMA is unmapped/released, as driver is likely + * doing refcnt based recycle tricks, meaning another process + * will be invoking put_page. + */ + recycle_stat_inc(pool, released_refcnt); + page_pool_return_page(pool, page); + + return NULL; +} + +void page_pool_put_defragged_page(struct page_pool *pool, struct page *page, + unsigned int dma_sync_size, bool allow_direct) +{ + page = __page_pool_put_page(pool, page, dma_sync_size, allow_direct); + if (page && !page_pool_recycle_in_ring(pool, page)) { + /* Cache full, fallback to free pages */ + recycle_stat_inc(pool, ring_full); + page_pool_return_page(pool, page); + } +} +EXPORT_SYMBOL(page_pool_put_defragged_page); + +/** + * page_pool_put_page_bulk() - release references on multiple pages + * @pool: pool from which pages were allocated + * @data: array holding page pointers + * @count: number of pages in @data + * + * Tries to refill a number of pages into the ptr_ring cache holding ptr_ring + * producer lock. If the ptr_ring is full, page_pool_put_page_bulk() + * will release leftover pages to the page allocator. + * page_pool_put_page_bulk() is suitable to be run inside the driver NAPI tx + * completion loop for the XDP_REDIRECT use case. + * + * Please note the caller must not use data area after running + * page_pool_put_page_bulk(), as this function overwrites it. + */ +void page_pool_put_page_bulk(struct page_pool *pool, void **data, + int count) +{ + int i, bulk_len = 0; + bool in_softirq; + + for (i = 0; i < count; i++) { + struct page *page = virt_to_head_page(data[i]); + + /* It is not the last user for the page frag case */ + if (!page_pool_is_last_frag(pool, page)) + continue; + + page = __page_pool_put_page(pool, page, -1, false); + /* Approved for bulk recycling in ptr_ring cache */ + if (page) + data[bulk_len++] = page; + } + + if (unlikely(!bulk_len)) + return; + + /* Bulk producer into ptr_ring page_pool cache */ + in_softirq = page_pool_producer_lock(pool); + for (i = 0; i < bulk_len; i++) { + if (__ptr_ring_produce(&pool->ring, data[i])) { + /* ring full */ + recycle_stat_inc(pool, ring_full); + break; + } + } + recycle_stat_add(pool, ring, i); + page_pool_producer_unlock(pool, in_softirq); + + /* Hopefully all pages was return into ptr_ring */ + if (likely(i == bulk_len)) + return; + + /* ptr_ring cache full, free remaining pages outside producer lock + * since put_page() with refcnt == 1 can be an expensive operation + */ + for (; i < bulk_len; i++) + page_pool_return_page(pool, data[i]); +} +EXPORT_SYMBOL(page_pool_put_page_bulk); + +static struct page *page_pool_drain_frag(struct page_pool *pool, + struct page *page) +{ + long drain_count = BIAS_MAX - pool->frag_users; + + /* Some user is still using the page frag */ + if (likely(page_pool_defrag_page(page, drain_count))) + return NULL; + + if (page_ref_count(page) == 1 && !page_is_pfmemalloc(page)) { + if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) + page_pool_dma_sync_for_device(pool, page, -1); + + return page; + } + + page_pool_return_page(pool, page); + return NULL; +} + +static void page_pool_free_frag(struct page_pool *pool) +{ + long drain_count = BIAS_MAX - pool->frag_users; + struct page *page = pool->frag_page; + + pool->frag_page = NULL; + + if (!page || page_pool_defrag_page(page, drain_count)) + return; + + page_pool_return_page(pool, page); +} + +struct page *page_pool_alloc_frag(struct page_pool *pool, + unsigned int *offset, + unsigned int size, gfp_t gfp) +{ + unsigned int max_size = PAGE_SIZE << pool->p.order; + struct page *page = pool->frag_page; + + if (WARN_ON(!(pool->p.flags & PP_FLAG_PAGE_FRAG) || + size > max_size)) + return NULL; + + size = ALIGN(size, dma_get_cache_alignment()); + *offset = pool->frag_offset; + + if (page && *offset + size > max_size) { + page = page_pool_drain_frag(pool, page); + if (page) { + alloc_stat_inc(pool, fast); + goto frag_reset; + } + } + + if (!page) { + page = page_pool_alloc_pages(pool, gfp); + if (unlikely(!page)) { + pool->frag_page = NULL; + return NULL; + } + + pool->frag_page = page; + +frag_reset: + pool->frag_users = 1; + *offset = 0; + pool->frag_offset = size; + page_pool_fragment_page(page, BIAS_MAX); + return page; + } + + pool->frag_users++; + pool->frag_offset = *offset + size; + alloc_stat_inc(pool, fast); + return page; +} +EXPORT_SYMBOL(page_pool_alloc_frag); + +static void page_pool_empty_ring(struct page_pool *pool) +{ + struct page *page; + + /* Empty recycle ring */ + while ((page = ptr_ring_consume_bh(&pool->ring))) { + /* Verify the refcnt invariant of cached pages */ + if (!(page_ref_count(page) == 1)) + pr_crit("%s() page_pool refcnt %d violation\n", + __func__, page_ref_count(page)); + + page_pool_return_page(pool, page); + } +} + +static void page_pool_free(struct page_pool *pool) +{ + if (pool->disconnect) + pool->disconnect(pool); + + ptr_ring_cleanup(&pool->ring, NULL); + + if (pool->p.flags & PP_FLAG_DMA_MAP) + put_device(pool->p.dev); + +#ifdef CONFIG_PAGE_POOL_STATS + free_percpu(pool->recycle_stats); +#endif + kfree(pool); +} + +static void page_pool_empty_alloc_cache_once(struct page_pool *pool) +{ + struct page *page; + + if (pool->destroy_cnt) + return; + + /* Empty alloc cache, assume caller made sure this is + * no-longer in use, and page_pool_alloc_pages() cannot be + * call concurrently. + */ + while (pool->alloc.count) { + page = pool->alloc.cache[--pool->alloc.count]; + page_pool_return_page(pool, page); + } +} + +static void page_pool_scrub(struct page_pool *pool) +{ + page_pool_empty_alloc_cache_once(pool); + pool->destroy_cnt++; + + /* No more consumers should exist, but producers could still + * be in-flight. + */ + page_pool_empty_ring(pool); +} + +static int page_pool_release(struct page_pool *pool) +{ + int inflight; + + page_pool_scrub(pool); + inflight = page_pool_inflight(pool); + if (!inflight) + page_pool_free(pool); + + return inflight; +} + +static void page_pool_release_retry(struct work_struct *wq) +{ + struct delayed_work *dwq = to_delayed_work(wq); + struct page_pool *pool = container_of(dwq, typeof(*pool), release_dw); + int inflight; + + inflight = page_pool_release(pool); + if (!inflight) + return; + + /* Periodic warning */ + if (time_after_eq(jiffies, pool->defer_warn)) { + int sec = (s32)((u32)jiffies - (u32)pool->defer_start) / HZ; + + pr_warn("%s() stalled pool shutdown %d inflight %d sec\n", + __func__, inflight, sec); + pool->defer_warn = jiffies + DEFER_WARN_INTERVAL; + } + + /* Still not ready to be disconnected, retry later */ + schedule_delayed_work(&pool->release_dw, DEFER_TIME); +} + +void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *), + struct xdp_mem_info *mem) +{ + refcount_inc(&pool->user_cnt); + pool->disconnect = disconnect; + pool->xdp_mem_id = mem->id; +} + +void page_pool_unlink_napi(struct page_pool *pool) +{ + if (!pool->p.napi) + return; + + /* To avoid races with recycling and additional barriers make sure + * pool and NAPI are unlinked when NAPI is disabled. + */ + WARN_ON(!test_bit(NAPI_STATE_SCHED, &pool->p.napi->state) || + READ_ONCE(pool->p.napi->list_owner) != -1); + + WRITE_ONCE(pool->p.napi, NULL); +} +EXPORT_SYMBOL(page_pool_unlink_napi); + +void page_pool_destroy(struct page_pool *pool) +{ + if (!pool) + return; + + if (!page_pool_put(pool)) + return; + + page_pool_unlink_napi(pool); + page_pool_free_frag(pool); + + if (!page_pool_release(pool)) + return; + + pool->defer_start = jiffies; + pool->defer_warn = jiffies + DEFER_WARN_INTERVAL; + + INIT_DELAYED_WORK(&pool->release_dw, page_pool_release_retry); + schedule_delayed_work(&pool->release_dw, DEFER_TIME); +} +EXPORT_SYMBOL(page_pool_destroy); + +/* Caller must provide appropriate safe context, e.g. NAPI. */ +void page_pool_update_nid(struct page_pool *pool, int new_nid) +{ + struct page *page; + + trace_page_pool_update_nid(pool, new_nid); + pool->p.nid = new_nid; + + /* Flush pool alloc cache, as refill will check NUMA node */ + while (pool->alloc.count) { + page = pool->alloc.cache[--pool->alloc.count]; + page_pool_return_page(pool, page); + } +} +EXPORT_SYMBOL(page_pool_update_nid); |