net: tap: change tap_alloc_skb() to allow bigger paged allocations

tap_alloc_skb() is currently calling sock_alloc_send_pskb()
forcing order-0 page allocations.

Switch to PAGE_ALLOC_COSTLY_ORDER, to increase max size by 8x.

Also add logic to increase the linear part if needed.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tahsin Erdogan <trdgn@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230801205254.400094-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 9137fb8..01574b9 100644 (file)
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -614,8 +614,10 @@ static inline struct sk_buff *tap_alloc_skb(struct sock *sk, size_t prepad,
        if (prepad + len < PAGE_SIZE || !linear)
                linear = len;
 
+       if (len - linear > MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
+               linear = len - MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER);
        skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
-                                  err, 0);
+                                  err, PAGE_ALLOC_COSTLY_ORDER);
        if (!skb)
                return NULL;