On 6/28/24 18:06, Willem de Bruijn wrote:
Pavel Begunkov wrote:
Instead of accounting every page range against the socket separately, do
it in batch based on the change in skb->truesize. It's also moved into
__zerocopy_sg_from_iter(), so that zerocopy_fill_skb_from_iter() is
simpler and responsible for setting frags but not the accounting.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Thanks for reviews!
---
net/core/datagram.c | 31 ++++++++++++++++++-------------
1 file changed, 18 insertions(+), 13 deletions(-)
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 7f7d5da2e406..2b24d69b1e94 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -610,7 +610,7 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
}
EXPORT_SYMBOL(skb_copy_datagram_from_iter);
-static int zerocopy_fill_skb_from_iter(struct sock *sk, struct sk_buff *skb,
+static int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
struct iov_iter *from, size_t length)
{
int frag = skb_shinfo(skb)->nr_frags;
@@ -621,7 +621,6 @@ static int zerocopy_fill_skb_from_iter(struct sock *sk, struct sk_buff *skb,
int refs, order, n = 0;
size_t start;
ssize_t copied;
- unsigned long truesize;
if (frag == MAX_SKB_FRAGS)
return -EMSGSIZE;
Does the existing code then incorrectly not unwind sk_wmem_queued_add
and sk_mem_charge if returning with error from the second or later
loop..
As long as ->truesize matches what's accounted to the socket,
kfree_skb() -> sock_wfree()/->destructor() should take care of it.
With sk_mem_charge() I assume __zerocopy_sg_from_iter -> ___pskb_trim()
should do it, need to look it up, but if not, it sounds like a temporary
over estimation until the skb is put down. I don't see anything
concerning. Is that the scenario you're worried about?
--
Pavel Begunkov
