| /* 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> |
| |
| #include "page_pool_priv.h" |
| |
| #define DEFER_TIME (msecs_to_jiffies(1000)) |
| #define DEFER_WARN_INTERVAL (60 * HZ) |
| |
| #define BIAS_MAX (LONG_MAX >> 1) |
| |
| #ifdef CONFIG_PAGE_POOL_STATS |
| static DEFINE_PER_CPU(struct page_pool_recycle_stats, pp_system_recycle_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(const 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, const void *stats) |
| { |
| const 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, |
| int cpuid) |
| { |
| unsigned int ring_qsize = 1024; /* Default */ |
| |
| memcpy(&pool->p, ¶ms->fast, sizeof(pool->p)); |
| memcpy(&pool->slow, ¶ms->slow, sizeof(pool->slow)); |
| |
| pool->cpuid = cpuid; |
| |
| /* 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 |
| */ |
| } |
| |
| pool->has_init_callback = !!pool->slow.init_callback; |
| |
| #ifdef CONFIG_PAGE_POOL_STATS |
| if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL)) { |
| pool->recycle_stats = alloc_percpu(struct page_pool_recycle_stats); |
| if (!pool->recycle_stats) |
| return -ENOMEM; |
| } else { |
| /* For system page pool instance we use a singular stats object |
| * instead of allocating a separate percpu variable for each |
| * (also percpu) page pool instance. |
| */ |
| pool->recycle_stats = &pp_system_recycle_stats; |
| } |
| #endif |
| |
| if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0) { |
| #ifdef CONFIG_PAGE_POOL_STATS |
| if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL)) |
| 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; |
| } |
| |
| static void page_pool_uninit(struct page_pool *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 |
| if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL)) |
| free_percpu(pool->recycle_stats); |
| #endif |
| } |
| |
| /** |
| * page_pool_create_percpu() - create a page pool for a given cpu. |
| * @params: parameters, see struct page_pool_params |
| * @cpuid: cpu identifier |
| */ |
| struct page_pool * |
| page_pool_create_percpu(const struct page_pool_params *params, int cpuid) |
| { |
| 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, cpuid); |
| if (err < 0) |
| goto err_free; |
| |
| err = page_pool_list(pool); |
| if (err) |
| goto err_uninit; |
| |
| return pool; |
| |
| err_uninit: |
| page_pool_uninit(pool); |
| err_free: |
| pr_warn("%s() gave up with errno %d\n", __func__, err); |
| kfree(pool); |
| return ERR_PTR(err); |
| } |
| EXPORT_SYMBOL(page_pool_create_percpu); |
| |
| /** |
| * 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) |
| { |
| return page_pool_create_percpu(params, -1); |
| } |
| 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(const struct page_pool *pool, |
| const 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; |
| |
| if (page_pool_set_dma_addr(page, dma)) |
| goto unmap_failed; |
| |
| if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) |
| page_pool_dma_sync_for_device(pool, page, pool->p.max_len); |
| |
| return true; |
| |
| unmap_failed: |
| WARN_ON_ONCE("unexpected DMA address, please report to netdev@"); |
| 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); |
| return false; |
| } |
| |
| static void page_pool_set_pp_info(struct page_pool *pool, |
| struct page *page) |
| { |
| page->pp = pool; |
| page->pp_magic |= PP_SIGNATURE; |
| |
| /* Ensuring all pages have been split into one fragment initially: |
| * page_pool_set_pp_info() is only called once for every page when it |
| * is allocated from the page allocator and page_pool_fragment_page() |
| * is dirtying the same cache line as the page->pp_magic above, so |
| * the overhead is negligible. |
| */ |
| page_pool_fragment_page(page, 1); |
| if (pool->has_init_callback) |
| pool->slow.init_callback(page, pool->slow.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)) |
| |
| s32 page_pool_inflight(const struct page_pool *pool, bool strict) |
| { |
| 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); |
| |
| if (strict) { |
| trace_page_pool_release(pool, inflight, hold_cnt, release_cnt); |
| WARN(inflight < 0, "Negative(%d) inflight packet-pages", |
| inflight); |
| } else { |
| inflight = max(0, inflight); |
| } |
| |
| return inflight; |
| } |
| |
| static __always_inline |
| void __page_pool_release_page_dma(struct page_pool *pool, struct page *page) |
| { |
| dma_addr_t dma; |
| |
| if (!(pool->p.flags & PP_FLAG_DMA_MAP)) |
| /* Always account for inflight pages, even if we didn't |
| * map them |
| */ |
| return; |
| |
| 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); |
| } |
| |
| /* 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). |
| */ |
| void page_pool_return_page(struct page_pool *pool, struct page *page) |
| { |
| int count; |
| |
| __page_pool_release_page_dma(pool, page); |
| |
| 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; |
| } |
| |
| static bool __page_pool_page_can_be_recycled(const struct page *page) |
| { |
| return page_ref_count(page) == 1 && !page_is_pfmemalloc(page); |
| } |
| |
| /* 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_pool_page_can_be_recycled(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 && 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; |
| } |
| |
| static bool page_pool_napi_local(const struct page_pool *pool) |
| { |
| const struct napi_struct *napi; |
| u32 cpuid; |
| |
| if (unlikely(!in_softirq())) |
| return false; |
| |
| /* Allow direct recycle if we have reasons to believe that we are |
| * in the same context as the consumer would run, so there's |
| * no possible race. |
| * __page_pool_put_page() makes sure we're not in hardirq context |
| * and interrupts are enabled prior to accessing the cache. |
| */ |
| cpuid = smp_processor_id(); |
| if (READ_ONCE(pool->cpuid) == cpuid) |
| return true; |
| |
| napi = READ_ONCE(pool->p.napi); |
| |
| return napi && READ_ONCE(napi->list_owner) == cpuid; |
| } |
| |
| void page_pool_put_unrefed_page(struct page_pool *pool, struct page *page, |
| unsigned int dma_sync_size, bool allow_direct) |
| { |
| if (!allow_direct) |
| allow_direct = page_pool_napi_local(pool); |
| |
| 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_unrefed_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 allow_direct; |
| bool in_softirq; |
| |
| allow_direct = page_pool_napi_local(pool); |
| |
| 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_ref(page)) |
| continue; |
| |
| page = __page_pool_put_page(pool, page, -1, allow_direct); |
| /* Approved for bulk recycling in ptr_ring cache */ |
| if (page) |
| data[bulk_len++] = page; |
| } |
| |
| if (!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_unref_page(page, drain_count))) |
| return NULL; |
| |
| if (__page_pool_page_can_be_recycled(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_unref_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(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_destroy(struct page_pool *pool) |
| { |
| if (pool->disconnect) |
| pool->disconnect(pool); |
| |
| page_pool_unlist(pool); |
| page_pool_uninit(pool); |
| 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, true); |
| if (!inflight) |
| __page_pool_destroy(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); |
| void *netdev; |
| int inflight; |
| |
| inflight = page_pool_release(pool); |
| if (!inflight) |
| return; |
| |
| /* Periodic warning for page pools the user can't see */ |
| netdev = READ_ONCE(pool->slow.netdev); |
| if (time_after_eq(jiffies, pool->defer_warn) && |
| (!netdev || netdev == NET_PTR_POISON)) { |
| int sec = (s32)((u32)jiffies - (u32)pool->defer_start) / HZ; |
| |
| pr_warn("%s() stalled pool shutdown: id %u, %d inflight %d sec\n", |
| __func__, pool->user.id, 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 *), |
| const struct xdp_mem_info *mem) |
| { |
| refcount_inc(&pool->user_cnt); |
| pool->disconnect = disconnect; |
| pool->xdp_mem_id = mem->id; |
| } |
| |
| static void page_pool_disable_direct_recycling(struct page_pool *pool) |
| { |
| /* Disable direct recycling based on pool->cpuid. |
| * Paired with READ_ONCE() in page_pool_napi_local(). |
| */ |
| WRITE_ONCE(pool->cpuid, -1); |
| |
| 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); |
| } |
| |
| void page_pool_destroy(struct page_pool *pool) |
| { |
| if (!pool) |
| return; |
| |
| if (!page_pool_put(pool)) |
| return; |
| |
| page_pool_disable_direct_recycling(pool); |
| page_pool_free_frag(pool); |
| |
| if (!page_pool_release(pool)) |
| return; |
| |
| page_pool_detached(pool); |
| 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); |