This patch implements __netdev_alloc_pages and __netdev_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.
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@xxxxxxxxxx>
---
include/linux/skbuff.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 103fbe8..f196628 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,
}
/**
+ * __netdev_alloc_pages - allocate page for ps-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 *__netdev_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 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 *netdev_alloc_pages(unsigned int order)
+{
+ return __netdev_alloc_pages(GFP_ATOMIC, order);
+}
+
+/**
+ * __netdev_alloc_page - allocate a page for ps-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 *__netdev_alloc_page(gfp_t gfp_mask)
+{
+ return __netdev_alloc_pages(gfp_mask, 0);
+}
+
+static inline struct page *netdev_alloc_page(void)
+{
+ return __netdev_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
--
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