* @node: numa node to allocate memory on
*
* Allocate a new &sk_buff. The returned buffer has no headroom and a
- * tail room of size bytes. The object has a reference count of one.
- * The return is the buffer. On a failure the return is %NULL.
+ * tail room of at least size bytes. The object has a reference count
+ * of one. The return is the buffer. On a failure the return is %NULL.
*
* Buffers may only be allocated from interrupts using a @gfp_mask of
* %GFP_ATOMIC.
struct netdev_alloc_cache {
struct page *page;
unsigned int offset;
+ unsigned int pagecnt_bias;
};
static DEFINE_PER_CPU(struct netdev_alloc_cache, netdev_alloc_cache);
+#define NETDEV_PAGECNT_BIAS (PAGE_SIZE / SMP_CACHE_BYTES)
+
/**
* netdev_alloc_frag - allocate a page fragment
* @fragsz: fragment size
if (unlikely(!nc->page)) {
refill:
nc->page = alloc_page(GFP_ATOMIC | __GFP_COLD);
+ if (unlikely(!nc->page))
+ goto end;
+recycle:
+ atomic_set(&nc->page->_count, NETDEV_PAGECNT_BIAS);
+ nc->pagecnt_bias = NETDEV_PAGECNT_BIAS;
nc->offset = 0;
}
- if (likely(nc->page)) {
- if (nc->offset + fragsz > PAGE_SIZE) {
- put_page(nc->page);
- goto refill;
- }
- data = page_address(nc->page) + nc->offset;
- nc->offset += fragsz;
- get_page(nc->page);
+
+ if (nc->offset + fragsz > PAGE_SIZE) {
+ /* avoid unnecessary locked operations if possible */
+ if ((atomic_read(&nc->page->_count) == nc->pagecnt_bias) ||
+ atomic_sub_and_test(nc->pagecnt_bias, &nc->page->_count))
+ goto recycle;
+ goto refill;
}
+
+ data = page_address(nc->page) + nc->offset;
+ nc->offset += fragsz;
+ nc->pagecnt_bias--;
+end:
local_irq_restore(flags);
return data;
}
}
EXPORT_SYMBOL_GPL(skb_morph);
-/* skb_copy_ubufs - copy userspace skb frags buffers to kernel
+/**
+ * skb_copy_ubufs - copy userspace skb frags buffers to kernel
* @skb: the skb to modify
* @gfp_mask: allocation priority
*
struct splice_pipe_desc spd = {
.pages = pages,
.partial = partial,
+ .nr_pages_max = MAX_SKB_FRAGS,
.flags = flags,
.ops = &sock_pipe_buf_ops,
.spd_release = sock_spd_release,
EXPORT_SYMBOL(skb_find_text);
/**
- * skb_append_datato_frags: - append the user data to a skb
+ * skb_append_datato_frags - append the user data to a skb
* @sk: sock structure
* @skb: skb structure to be appened with user data.
* @getfrag: call back function to be used for getting the user data