[RFC v4 05/18] page_pool: use netmem alloc/put APIs in __page_pool_alloc_pages_slow()

Byungchul Park
2025-06-04T02:53:04Z

Use netmem alloc/put APIs instead of page alloc/put APIs in
__page_pool_alloc_pages_slow().

While at it, improved some comments.

Signed-off-by: Byungchul Park <byungchul@sk.com>
Reviewed-by: Mina Almasry <almasrymina@google.com>
---
net/core/page_pool.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index ff3d0d31263c..e80a637f0fa4 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -551,7 +551,7 @@ static noinline netmem_ref __page_pool_alloc_pages_slow(struct page_pool *pool,
unsigned int pp_order = pool->p.order;
bool dma_map = pool->dma_map;
netmem_ref netmem;
- int i, nr_pages;
+ int i, nr_netmems;

/* Don't support bulk alloc for high-order pages */
if (unlikely(pp_order))
@@ -561,21 +561,21 @@ static noinline netmem_ref __page_pool_alloc_pages_slow(struct page_pool *pool,
if (unlikely(pool->alloc.count > 0))
return pool->alloc.cache[--pool->alloc.count];

- /* Mark empty alloc.cache slots "empty" for alloc_pages_bulk */
+ /* Mark empty alloc.cache slots "empty" for alloc_netmems_bulk_node() */
memset(&pool->alloc.cache, 0, sizeof(void *) * bulk);

- nr_pages = alloc_pages_bulk_node(gfp, pool->p.nid, bulk,
- (struct page **)pool->alloc.cache);
- if (unlikely(!nr_pages))
+ nr_netmems = alloc_netmems_bulk_node(gfp, pool->p.nid, bulk,
+ pool->alloc.cache);
+ if (unlikely(!nr_netmems))
return 0;

- /* Pages have been filled into alloc.cache array, but count is zero and
- * page element have not been (possibly) DMA mapped.
+ /* Netmems have been filled into alloc.cache array, but count is
+ * zero and elements have not been (possibly) DMA mapped.
*/
- for (i = 0; i < nr_pages; i++) {
+ for (i = 0; i < nr_netmems; i++) {
netmem = pool->alloc.cache[i];
if (dma_map && unlikely(!page_pool_dma_map(pool, netmem, gfp))) {
- put_page(netmem_to_page(netmem));
+ put_netmem(netmem);
continue;
}

@@ -587,7 +587,7 @@ static noinline netmem_ref __page_pool_alloc_pages_slow(struct page_pool *pool,
pool->pages_state_hold_cnt);
}

- /* Return last page */
+ /* Return the last netmem */
if (likely(pool->alloc.count > 0)) {
netmem = pool->alloc.cache[--pool->alloc.count];
alloc_stat_inc(pool, slow);
@@ -595,7 +595,9 @@ static noinline netmem_ref __page_pool_alloc_pages_slow(struct page_pool *pool,
netmem = 0;
}

- /* When page just alloc'ed is should/must have refcnt 1. */
+ /* When a netmem has been just allocated, it should/must have
+ * refcnt 1.
+ */
return netmem;
}

--
2.17.1