From 71dfda58aaaf4bf6b1bc59f9d8afa635fa1337d4 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Tue, 11 Nov 2014 09:26:34 -0800 Subject: [PATCH] net: Add device Rx page allocation function This patch implements __dev_alloc_pages and __dev_alloc_page. These are meant to replace the __skb_alloc_pages and __skb_alloc_page functions. The reason for doing this is that it occurred to me that __skb_alloc_page is supposed to be passed an sk_buff pointer, but it is NULL in all cases where it is used. Worse is that in the case of ixgbe it is passed NULL via the sk_buff pointer in the rx_buffer info structure which means the compiler is not correctly stripping it out. The naming for these functions is based on dev_alloc_skb and __dev_alloc_skb. There was originally a netdev_alloc_page, however that was passed a net_device pointer and this function is not so I thought it best to follow that naming scheme since that is the same difference between dev_alloc_skb and netdev_alloc_skb. In the case of anything greater than order 0 it is assumed that we want a compound page so __GFP_COMP is set for all allocations as we expect a compound page when assigning a page frag. The other change in this patch is to exploit the behaviors of the page allocator in how it handles flags. So for example we can always set __GFP_COMP and __GFP_MEMALLOC since they are ignored if they are not applicable or are overridden by another flag. Signed-off-by: Alexander Duyck Signed-off-by: David S. Miller --- include/linux/skbuff.h | 48 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 103fbe8113f8..2e5221f1ec72 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2184,6 +2184,54 @@ static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev, return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC); } +/** + * __dev_alloc_pages - allocate page for network Rx + * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx + * @order: size of the allocation + * + * Allocate a new page. + * + * %NULL is returned if there is no free memory. +*/ +static inline struct page *__dev_alloc_pages(gfp_t gfp_mask, + unsigned int order) +{ + /* This piece of code contains several assumptions. + * 1. This is for device Rx, therefor a cold page is preferred. + * 2. The expectation is the user wants a compound page. + * 3. If requesting a order 0 page it will not be compound + * due to the check to see if order has a value in prep_new_page + * 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to + * code in gfp_to_alloc_flags that should be enforcing this. + */ + gfp_mask |= __GFP_COLD | __GFP_COMP | __GFP_MEMALLOC; + + return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order); +} + +static inline struct page *dev_alloc_pages(unsigned int order) +{ + return __dev_alloc_pages(GFP_ATOMIC, order); +} + +/** + * __dev_alloc_page - allocate a page for network Rx + * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx + * + * Allocate a new page. + * + * %NULL is returned if there is no free memory. + */ +static inline struct page *__dev_alloc_page(gfp_t gfp_mask) +{ + return __dev_alloc_pages(gfp_mask, 0); +} + +static inline struct page *dev_alloc_page(void) +{ + return __dev_alloc_page(GFP_ATOMIC); +} + /** * __skb_alloc_pages - allocate pages for ps-rx on a skb and preserve pfmemalloc data * @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX -- 2.20.1