From ad6fa1e1ab1b8164f1ba296b1b4dc556a483bcad Mon Sep 17 00:00:00 2001 From: Joe Damato Date: Tue, 1 Mar 2022 23:55:48 -0800 Subject: [PATCH 2/3] page_pool: Add recycle stats Add per-cpu stats tracking page pool recycling events: - cached: recycling placed page in the page pool cache - cache_full: page pool cache was full - ring: page placed into the ptr ring - ring_full: page released from page pool because the ptr ring was full - released_refcnt: page released (and not recycled) because refcnt > 1 Signed-off-by: Joe Damato Acked-by: Jesper Dangaard Brouer Reviewed-by: Ilias Apalodimas Signed-off-by: David S. Miller --- include/net/page_pool.h | 16 ++++++++++++++++ net/core/page_pool.c | 30 ++++++++++++++++++++++++++++-- 2 files changed, 44 insertions(+), 2 deletions(-) --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -93,6 +93,18 @@ struct page_pool_alloc_stats { u64 refill; /* allocations via successful refill */ u64 waive; /* failed refills due to numa zone mismatch */ }; + +struct page_pool_recycle_stats { + u64 cached; /* recycling placed page in the cache. */ + u64 cache_full; /* cache was full */ + u64 ring; /* recycling placed page back into ptr ring */ + u64 ring_full; /* page was released from page-pool because + * PTR ring was full. + */ + u64 released_refcnt; /* page released because of elevated + * refcnt + */ +}; #endif struct page_pool { @@ -136,6 +148,10 @@ struct page_pool { */ struct ptr_ring ring; +#ifdef CONFIG_PAGE_POOL_STATS + /* recycle stats are per-cpu to avoid locking */ + struct page_pool_recycle_stats __percpu *recycle_stats; +#endif atomic_t pages_state_release_cnt; /* A page_pool is strictly tied to a single RX-queue being --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -29,8 +29,15 @@ #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) #else #define alloc_stat_inc(pool, __stat) +#define recycle_stat_inc(pool, __stat) #endif static int page_pool_init(struct page_pool *pool, @@ -80,6 +87,12 @@ static int page_pool_init(struct page_po 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) return -ENOMEM; @@ -412,7 +425,12 @@ static bool page_pool_recycle_in_ring(st else ret = ptr_ring_produce_bh(&pool->ring, page); - return (ret == 0) ? true : false; + if (!ret) { + recycle_stat_inc(pool, ring); + return true; + } + + return false; } /* Only allow direct recycling in special circumstances, into the @@ -423,11 +441,14 @@ static bool page_pool_recycle_in_ring(st static bool page_pool_recycle_in_cache(struct page *page, struct page_pool *pool) { - if (unlikely(pool->alloc.count == PP_ALLOC_CACHE_SIZE)) + 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; } @@ -482,6 +503,7 @@ __page_pool_put_page(struct page_pool *p * doing refcnt based recycle tricks, meaning another process * will be invoking put_page. */ + recycle_stat_inc(pool, released_refcnt); /* Do not replace this with page_pool_return_page() */ page_pool_release_page(pool, page); put_page(page); @@ -495,6 +517,7 @@ void page_pool_put_page(struct page_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); } } @@ -641,6 +664,9 @@ static void page_pool_free(struct page_p 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); }