summaryrefslogtreecommitdiffstats
path: root/net/core/page_pool.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/core/page_pool.c')
-rw-r--r--net/core/page_pool.c943
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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 05:07:03 +0000