Re: [RFC PATCH net-next v7 06/14] page_pool: convert to use netmem
On Tue, Mar 26, 2024 at 3:51 PM Mina Almasry wrote:
>
> Abstrace the memory type from the page_pool so we can later add support
> for new memory types. Convert the page_pool to use the new netmem type
> abstraction, rather than use struct page directly.
>
> As of this patch the netmem type is a no-op abstraction: it's always a
> struct page underneath. All the page pool internals are converted to
> use struct netmem instead of struct page, and the page pool now exports
> 2 APIs:
>
> 1. The existing struct page API.
> 2. The new struct netmem API.
>
> Keeping the existing API is transitional; we do not want to refactor all
> the current drivers using the page pool at once.
>
> The netmem abstraction is currently a no-op. The page_pool uses
> page_to_netmem() to convert allocated pages to netmem, and uses
> netmem_to_page() to convert the netmem back to pages to pass to mm APIs,
>
> Follow up patches to this series add non-paged netmem support to the
> page_pool. This change is factored out on its own to limit the code
> churn to this 1 patch, for ease of code review.
>
> Signed-off-by: Mina Almasry
>
> ---
>
> v6:
>
> - Rebased on top of the merged netmem_ref type.
>
> To: linux...@kvack.org
It looks like this tag to add linux-mm did not work as intended. CCing
linux-mm manually.
> Cc: Matthew Wilcox
>
> ---
> include/linux/skbuff.h | 4 +-
> include/net/netmem.h | 15 ++
> include/net/page_pool/helpers.h | 122 +
> include/net/page_pool/types.h| 17 +-
> include/trace/events/page_pool.h | 29 +--
> net/bpf/test_run.c | 5 +-
> net/core/page_pool.c | 303 +--
> net/core/skbuff.c| 7 +-
> 8 files changed, 302 insertions(+), 200 deletions(-)
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index b945af8a6208..78659c8efa4e 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -3521,7 +3521,7 @@ int skb_pp_cow_data(struct page_pool *pool, struct
> sk_buff **pskb,
> unsigned int headroom);
> int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
> struct bpf_prog *prog);
> -bool napi_pp_put_page(struct page *page, bool napi_safe);
> +bool napi_pp_put_page(netmem_ref netmem, bool napi_safe);
>
> static inline void
> skb_page_unref(const struct sk_buff *skb, struct page *page, bool napi_safe)
> @@ -3539,7 +3539,7 @@ 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 && napi_pp_put_page(page, napi_safe))
> + if (recycle && napi_pp_put_page(page_to_netmem(page), napi_safe))
> return;
> #endif
> put_page(page);
> diff --git a/include/net/netmem.h b/include/net/netmem.h
> index ca17ea1d33f8..21f53b29e5fe 100644
> --- a/include/net/netmem.h
> +++ b/include/net/netmem.h
> @@ -88,4 +88,19 @@ static inline netmem_ref page_to_netmem(struct page *page)
> return (__force netmem_ref)page;
> }
>
> +static inline int netmem_ref_count(netmem_ref netmem)
> +{
> + return page_ref_count(netmem_to_page(netmem));
> +}
> +
> +static inline unsigned long netmem_to_pfn(netmem_ref netmem)
> +{
> + return page_to_pfn(netmem_to_page(netmem));
> +}
> +
> +static inline netmem_ref netmem_compound_head(netmem_ref netmem)
> +{
> + return page_to_netmem(compound_head(netmem_to_page(netmem)));
> +}
> +
> #endif /* _NET_NETMEM_H */
> diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h
> index 1d397c1a0043..61814f91a458 100644
> --- a/include/net/page_pool/helpers.h
> +++ b/include/net/page_pool/helpers.h
> @@ -53,6 +53,8 @@
> #define _NET_PAGE_POOL_HELPERS_H
>
> #include
> +#include
> +#include
>
> #ifdef CONFIG_PAGE_POOL_STATS
> /* Deprecated driver-facing API, use netlink instead */
> @@ -101,7 +103,7 @@ static inline struct page
> *page_pool_dev_alloc_pages(struct page_pool *pool)
> * Get a page fragment from the page allocator or page_pool caches.
> *
> * Return:
> - * Return allocated page fragment, otherwise return NULL.
> + * Return allocated page fragment, otherwise return 0.
> */
> static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
> unsigned int *offset,
> @@ -112,22 +114,22 @@ static inline struct page
> *page_pool_dev_alloc_frag(struct page_pool *pool,
> return page_pool_alloc_frag(pool, offset, size, gfp);
> }
>
> -static inline struct page *page_pool_alloc(struct page_pool *pool,
> - unsigned int *offset,
> - unsigned int *size, gfp_t gfp)
> +static inline netmem_ref page_pool_alloc(struct page_pool *pool,
> +unsigned int *offset,
> +unsigned int *
[RFC PATCH net-next v7 06/14] page_pool: convert to use netmem
Abstrace the memory type from the page_pool so we can later add support
for new memory types. Convert the page_pool to use the new netmem type
abstraction, rather than use struct page directly.
As of this patch the netmem type is a no-op abstraction: it's always a
struct page underneath. All the page pool internals are converted to
use struct netmem instead of struct page, and the page pool now exports
2 APIs:
1. The existing struct page API.
2. The new struct netmem API.
Keeping the existing API is transitional; we do not want to refactor all
the current drivers using the page pool at once.
The netmem abstraction is currently a no-op. The page_pool uses
page_to_netmem() to convert allocated pages to netmem, and uses
netmem_to_page() to convert the netmem back to pages to pass to mm APIs,
Follow up patches to this series add non-paged netmem support to the
page_pool. This change is factored out on its own to limit the code
churn to this 1 patch, for ease of code review.
Signed-off-by: Mina Almasry
---
v6:
- Rebased on top of the merged netmem_ref type.
To: linux...@kvack.org
Cc: Matthew Wilcox
---
include/linux/skbuff.h | 4 +-
include/net/netmem.h | 15 ++
include/net/page_pool/helpers.h | 122 +
include/net/page_pool/types.h| 17 +-
include/trace/events/page_pool.h | 29 +--
net/bpf/test_run.c | 5 +-
net/core/page_pool.c | 303 +--
net/core/skbuff.c| 7 +-
8 files changed, 302 insertions(+), 200 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b945af8a6208..78659c8efa4e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3521,7 +3521,7 @@ int skb_pp_cow_data(struct page_pool *pool, struct
sk_buff **pskb,
unsigned int headroom);
int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
struct bpf_prog *prog);
-bool napi_pp_put_page(struct page *page, bool napi_safe);
+bool napi_pp_put_page(netmem_ref netmem, bool napi_safe);
static inline void
skb_page_unref(const struct sk_buff *skb, struct page *page, bool napi_safe)
@@ -3539,7 +3539,7 @@ 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 && napi_pp_put_page(page, napi_safe))
+ if (recycle && napi_pp_put_page(page_to_netmem(page), napi_safe))
return;
#endif
put_page(page);
diff --git a/include/net/netmem.h b/include/net/netmem.h
index ca17ea1d33f8..21f53b29e5fe 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -88,4 +88,19 @@ static inline netmem_ref page_to_netmem(struct page *page)
return (__force netmem_ref)page;
}
+static inline int netmem_ref_count(netmem_ref netmem)
+{
+ return page_ref_count(netmem_to_page(netmem));
+}
+
+static inline unsigned long netmem_to_pfn(netmem_ref netmem)
+{
+ return page_to_pfn(netmem_to_page(netmem));
+}
+
+static inline netmem_ref netmem_compound_head(netmem_ref netmem)
+{
+ return page_to_netmem(compound_head(netmem_to_page(netmem)));
+}
+
#endif /* _NET_NETMEM_H */
diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h
index 1d397c1a0043..61814f91a458 100644
--- a/include/net/page_pool/helpers.h
+++ b/include/net/page_pool/helpers.h
@@ -53,6 +53,8 @@
#define _NET_PAGE_POOL_HELPERS_H
#include
+#include
+#include
#ifdef CONFIG_PAGE_POOL_STATS
/* Deprecated driver-facing API, use netlink instead */
@@ -101,7 +103,7 @@ static inline struct page *page_pool_dev_alloc_pages(struct
page_pool *pool)
* Get a page fragment from the page allocator or page_pool caches.
*
* Return:
- * Return allocated page fragment, otherwise return NULL.
+ * Return allocated page fragment, otherwise return 0.
*/
static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
unsigned int *offset,
@@ -112,22 +114,22 @@ static inline struct page
*page_pool_dev_alloc_frag(struct page_pool *pool,
return page_pool_alloc_frag(pool, offset, size, gfp);
}
-static inline struct page *page_pool_alloc(struct page_pool *pool,
- unsigned int *offset,
- unsigned int *size, gfp_t gfp)
+static inline netmem_ref page_pool_alloc(struct page_pool *pool,
+unsigned int *offset,
+unsigned int *size, gfp_t gfp)
{
unsigned int max_size = PAGE_SIZE << pool->p.order;
- struct page *page;
+ netmem_ref netmem;
if ((*size << 1) > max_size) {
*size = max_size;
*offset = 0;
- return page_pool_alloc_pages(pool, gfp);
+ return page_pool_alloc_netmem(pool, gfp);
}
- page
