diff options
| -rw-r--r-- | net/core/skbuff.c | 72 |
1 files changed, 67 insertions, 5 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index c1232837cd0c..bdb1e015e32b 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -89,6 +89,34 @@ static struct kmem_cache *skbuff_fclone_cache __ro_after_init; #ifdef CONFIG_SKB_EXTENSIONS static struct kmem_cache *skbuff_ext_cache __ro_after_init; #endif + +/* skb_small_head_cache and related code is only supported + * for CONFIG_SLAB and CONFIG_SLUB. + * As soon as SLOB is removed from the kernel, we can clean up this. + */ +#if !defined(CONFIG_SLOB) +# define HAVE_SKB_SMALL_HEAD_CACHE 1 +#endif + +#ifdef HAVE_SKB_SMALL_HEAD_CACHE +static struct kmem_cache *skb_small_head_cache __ro_after_init; + +#define SKB_SMALL_HEAD_SIZE SKB_HEAD_ALIGN(MAX_TCP_HEADER) + +/* We want SKB_SMALL_HEAD_CACHE_SIZE to not be a power of two. + * This should ensure that SKB_SMALL_HEAD_HEADROOM is a unique + * size, and we can differentiate heads from skb_small_head_cache + * vs system slabs by looking at their size (skb_end_offset()). + */ +#define SKB_SMALL_HEAD_CACHE_SIZE \ + (is_power_of_2(SKB_SMALL_HEAD_SIZE) ? \ + (SKB_SMALL_HEAD_SIZE + L1_CACHE_BYTES) : \ + SKB_SMALL_HEAD_SIZE) + +#define SKB_SMALL_HEAD_HEADROOM \ + SKB_WITH_OVERHEAD(SKB_SMALL_HEAD_CACHE_SIZE) +#endif /* HAVE_SKB_SMALL_HEAD_CACHE */ + int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS; EXPORT_SYMBOL(sysctl_max_skb_frags); @@ -486,6 +514,23 @@ static void *kmalloc_reserve(unsigned int *size, gfp_t flags, int node, void *obj; obj_size = SKB_HEAD_ALIGN(*size); +#ifdef HAVE_SKB_SMALL_HEAD_CACHE + if (obj_size <= SKB_SMALL_HEAD_CACHE_SIZE && + !(flags & KMALLOC_NOT_NORMAL_BITS)) { + + /* skb_small_head_cache has non power of two size, + * likely forcing SLUB to use order-3 pages. + * We deliberately attempt a NOMEMALLOC allocation only. + */ + obj = kmem_cache_alloc_node(skb_small_head_cache, + flags | __GFP_NOMEMALLOC | __GFP_NOWARN, + node); + if (obj) { + *size = SKB_SMALL_HEAD_CACHE_SIZE; + goto out; + } + } +#endif *size = obj_size = kmalloc_size_roundup(obj_size); /* * Try a regular allocation, when that fails and we're not entitled @@ -805,6 +850,16 @@ static bool skb_pp_recycle(struct sk_buff *skb, void *data) return page_pool_return_skb_page(virt_to_page(data)); } +static void skb_kfree_head(void *head, unsigned int end_offset) +{ +#ifdef HAVE_SKB_SMALL_HEAD_CACHE + if (end_offset == SKB_SMALL_HEAD_HEADROOM) + kmem_cache_free(skb_small_head_cache, head); + else +#endif + kfree(head); +} + static void skb_free_head(struct sk_buff *skb) { unsigned char *head = skb->head; @@ -814,7 +869,7 @@ static void skb_free_head(struct sk_buff *skb) return; skb_free_frag(head); } else { - kfree(head); + skb_kfree_head(head, skb_end_offset(skb)); } } @@ -1997,7 +2052,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, return 0; nofrags: - kfree(data); + skb_kfree_head(data, size); nodata: return -ENOMEM; } @@ -4634,6 +4689,13 @@ void __init skb_init(void) 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); +#ifdef HAVE_SKB_SMALL_HEAD_CACHE + skb_small_head_cache = kmem_cache_create("skbuff_small_head", + SKB_SMALL_HEAD_CACHE_SIZE, + 0, + SLAB_HWCACHE_ALIGN | SLAB_PANIC, + NULL); +#endif skb_extensions_init(); } @@ -6298,7 +6360,7 @@ static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off, if (skb_cloned(skb)) { /* drop the old head gracefully */ if (skb_orphan_frags(skb, gfp_mask)) { - kfree(data); + skb_kfree_head(data, size); return -ENOMEM; } for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) @@ -6406,7 +6468,7 @@ static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off, memcpy((struct skb_shared_info *)(data + size), skb_shinfo(skb), offsetof(struct skb_shared_info, frags[0])); if (skb_orphan_frags(skb, gfp_mask)) { - kfree(data); + skb_kfree_head(data, size); return -ENOMEM; } shinfo = (struct skb_shared_info *)(data + size); @@ -6442,7 +6504,7 @@ static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off, /* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */ if (skb_has_frag_list(skb)) kfree_skb_list(skb_shinfo(skb)->frag_list); - kfree(data); + skb_kfree_head(data, size); return -ENOMEM; } skb_release_data(skb, SKB_CONSUMED); |