Commit 75eaf63e authored by Alexander Lobakin's avatar Alexander Lobakin Committed by Jakub Kicinski
Browse files

net: skbuff: don't include <net/page_pool/types.h> to <linux/skbuff.h> 



Currently, touching <net/page_pool/types.h> triggers a rebuild of more
than half of the kernel. That's because it's included in
<linux/skbuff.h>. And each new include to page_pool/types.h adds more
[useless] data for the toolchain to process per each source file from
that pile.

In commit 6a5bcd84 ("page_pool: Allow drivers to hint on SKB
recycling"), Matteo included it to be able to call a couple of functions
defined there. Then, in commit 57f05bc2 ("page_pool: keep pp info as
long as page pool owns the page") one of the calls was removed, so only
one was left. It's the call to page_pool_return_skb_page() in
napi_frag_unref(). The function is external and doesn't have any
dependencies. Having very niche page_pool_types.h included only for that
looks like an overkill.

As %PP_SIGNATURE is not local to page_pool.c (was only in the
early submissions), nothing holds this function there. Teleport
page_pool_return_skb_page() to skbuff.c, just next to the main consumer,
skb_pp_recycle(), and rename it to napi_pp_put_page(), as it doesn't
work with skbs at all and the former name tells nothing. The #if guards
here are only to not compile and have it in the vmlinux when not needed
-- both call sites are already guarded.
Now, touching page_pool_types.h only triggers rebuilding of the drivers
using it and a couple of core networking files.

Suggested-by: Jakub Kicinski <kuba@kernel.org> # make skbuff.h less heavy
Suggested-by: Alexander Duyck <alexanderduyck@fb.com> # move to skbuff.c
Signed-off-by: default avatarAlexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: default avatarAlexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/20230804180529.2483231-3-aleksander.lobakin@intel.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a9ca9f9c

include/linux/skbuff.h

+3 −2
Original line number Diff line number Diff line
@@ -32,7 +32,6 @@ 
#include <linux/if_packet.h>

#include <linux/llist.h>

#include <net/flow.h>

#include <net/page_pool/types.h>

#if IS_ENABLED(CONFIG_NF_CONNTRACK)

#include <linux/netfilter/nf_conntrack_common.h>

#endif
@@ -3421,13 +3420,15 @@ static inline void skb_frag_ref(struct sk_buff *skb, int f) 
	__skb_frag_ref(&skb_shinfo(skb)->frags[f]);

}



bool napi_pp_put_page(struct page *page, bool napi_safe);



static inline void

napi_frag_unref(skb_frag_t *frag, bool recycle, bool napi_safe)

{

	struct page *page = skb_frag_page(frag);



#ifdef CONFIG_PAGE_POOL

	if (recycle && page_pool_return_skb_page(page, napi_safe))

	if (recycle && napi_pp_put_page(page, napi_safe))

		return;

#endif

	put_page(page);

include/net/page_pool/types.h

+0 −2
Original line number Diff line number Diff line
@@ -185,8 +185,6 @@ struct page_pool { 
struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);

struct page *page_pool_alloc_frag(struct page_pool *pool, unsigned int *offset,

				  unsigned int size, gfp_t gfp);

bool page_pool_return_skb_page(struct page *page, bool napi_safe);



struct page_pool *page_pool_create(const struct page_pool_params *params);



struct xdp_mem_info;

net/core/page_pool.c

+0 −39
Original line number Diff line number Diff line
@@ -935,42 +935,3 @@ void page_pool_update_nid(struct page_pool *pool, int new_nid) 
	}

}

EXPORT_SYMBOL(page_pool_update_nid);
 


bool page_pool_return_skb_page(struct page *page, bool napi_safe)

{

	struct napi_struct *napi;

	struct page_pool *pp;

	bool allow_direct;



	page = compound_head(page);



	/* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation

	 * in order to preserve any existing bits, such as bit 0 for the

	 * head page of compound page and bit 1 for pfmemalloc page, so

	 * mask those bits for freeing side when doing below checking,

	 * and page_is_pfmemalloc() is checked in __page_pool_put_page()

	 * to avoid recycling the pfmemalloc page.

	 */

	if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE))

		return false;



	pp = page->pp;



	/* Allow direct recycle if we have reasons to believe that we are

	 * in the same context as the consumer would run, so there's

	 * no possible race.

	 */

	napi = READ_ONCE(pp->p.napi);

	allow_direct = napi_safe && napi &&

		READ_ONCE(napi->list_owner) == smp_processor_id();



	/* Driver set this to memory recycling info. Reset it on recycle.

	 * This will *not* work for NIC using a split-page memory model.

	 * The page will be returned to the pool here regardless of the

	 * 'flipped' fragment being in use or not.

	 */

	page_pool_put_full_page(pp, page, allow_direct);



	return true;

}

EXPORT_SYMBOL(page_pool_return_skb_page);

net/core/skbuff.c

+43 −2
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ 
#include <net/mpls.h>

#include <net/mptcp.h>

#include <net/mctp.h>

#include <net/page_pool/types.h>

#include <net/page_pool/helpers.h>

#include <net/dropreason.h>



#include <linux/uaccess.h>
@@ -879,11 +879,52 @@ static void skb_clone_fraglist(struct sk_buff *skb) 
		skb_get(list);

}



#if IS_ENABLED(CONFIG_PAGE_POOL)

bool napi_pp_put_page(struct page *page, bool napi_safe)

{

	struct napi_struct *napi;

	struct page_pool *pp;

	bool allow_direct;



	page = compound_head(page);



	/* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation

	 * in order to preserve any existing bits, such as bit 0 for the

	 * head page of compound page and bit 1 for pfmemalloc page, so

	 * mask those bits for freeing side when doing below checking,

	 * and page_is_pfmemalloc() is checked in __page_pool_put_page()

	 * to avoid recycling the pfmemalloc page.

	 */

	if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE))

		return false;



	pp = page->pp;



	/* Allow direct recycle if we have reasons to believe that we are

	 * in the same context as the consumer would run, so there's

	 * no possible race.

	 */

	napi = READ_ONCE(pp->p.napi);

	allow_direct = napi_safe && napi &&

		READ_ONCE(napi->list_owner) == smp_processor_id();



	/* Driver set this to memory recycling info. Reset it on recycle.

	 * This will *not* work for NIC using a split-page memory model.

	 * The page will be returned to the pool here regardless of the

	 * 'flipped' fragment being in use or not.

	 */

	page_pool_put_full_page(pp, page, allow_direct);



	return true;

}

EXPORT_SYMBOL(napi_pp_put_page);

#endif



static bool skb_pp_recycle(struct sk_buff *skb, void *data, bool napi_safe)

{

	if (!IS_ENABLED(CONFIG_PAGE_POOL) || !skb->pp_recycle)

		return false;

	return page_pool_return_skb_page(virt_to_page(data), napi_safe);

	return napi_pp_put_page(virt_to_page(data), napi_safe);

}



static void skb_kfree_head(void *head, unsigned int end_offset)