diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/skbuff.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 506f678..8b6d38f 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -296,9 +296,12 @@ EXPORT_SYMBOL(build_skb); 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 @@ -317,17 +320,26 @@ void *netdev_alloc_frag(unsigned int fragsz) 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; } |