Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 71dfda58 authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

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: default avatarAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6c91023d

include/linux/skbuff.h

+48 −0
Original line number Diff line number Diff line
@@ -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