Re: [PATCH v2 02/16] netmem: introduce netmem alloc APIs to wrap page alloc APIs

On Tue, May 27, 2025 at 08:11:58PM -0700, Mina Almasry wrote:

On Tue, May 27, 2025 at 7:29 PM Byungchul Park [off-list ref] wrote:

quoted

To eliminate the use of struct page in page pool, the page pool code
should use netmem descriptor and APIs instead.

As part of the work, introduce netmem alloc APIs allowing the code to
use them rather than the existing APIs for struct page.

Signed-off-by: Byungchul Park <byungchul@sk.com>
---
 include/net/netmem.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/net/netmem.h b/include/net/netmem.h
index a721f9e060a2..37d0e0e002c2 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h

@@ -177,6 +177,19 @@ static inline netmem_ref page_to_netmem(struct page *page)
        return (__force netmem_ref)page;
 }

+static inline netmem_ref alloc_netmems_node(int nid, gfp_t gfp_mask,
+               unsigned int order)
+{
+       return page_to_netmem(alloc_pages_node(nid, gfp_mask, order));
+}
+
+static inline unsigned long alloc_netmems_bulk_node(gfp_t gfp, int nid,
+               unsigned long nr_netmems, netmem_ref *netmem_array)
+{
+       return alloc_pages_bulk_node(gfp, nid, nr_netmems,
+                       (struct page **)netmem_array);
+}
+
 /**
  * virt_to_netmem - convert virtual memory pointer to a netmem reference
  * @data: host memory pointer to convert

Code looks fine to me, but I'm not sure we want to export these
helpers in include/net where they're available to the entire kernel
and net stack. Can we put these helpers in net/core/page_pool.c or at
least net/core/netmem_priv.h?

Thanks.  I will.

Also maybe the helpers aren't needed anyway. AFAICT there is only 1
call site in page_pool.c for each, so maybe we can implement this
inline.

Sure.

	Byungchul

-- 
Thanks,
Mina