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authorAlexander Duyck <alexander.h.duyck@redhat.com>2014-11-11 09:26:34 -0800
committerDavid S. Miller <davem@davemloft.net>2014-11-12 00:00:13 -0500
commit71dfda58aaaf4bf6b1bc59f9d8afa635fa1337d4 (patch)
treefd74fc18415b7269e1a1f0f078bc77093c40e74a
parent6c91023dc35c88d5e6aebe4bfe6f1ed5ec2b84be (diff)
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 <alexander.h.duyck@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/skbuff.h48
1 files changed, 48 insertions, 0 deletions
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
@@ -2185,6 +2185,54 @@ static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
}
/**
+ * __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
* @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used