Re: bug in 2.1.89 include/net/sock.h?

Linus Torvalds (torvalds@transmeta.com)
Sun, 22 Mar 1998 15:16:03 -0800 (PST)

On Sun, 22 Mar 1998, David S. Miller wrote:
>
> Something like
>
> /* Wake up only if we have more than half the wspace free: */
> if (atomic_read(sk->wmem_alloc)*2 <= sk->sndbuf)) {
> ... wake_up() ..
> }
>
> should get rid of some unnecessary wake-ups, whether they are due
> to ACK's or not. There's no point in having the writer trickle the
> write data in small chunks anyway.
>
> Sounds good. As Alexey mentioned, this was exactly what the code used
> to do a long time ago, but the conditional disappeared early in the
> 2.1.x series.

Yes, I think I may have been responsible for that code in 2.0.x.. I was
surprised that it looked like it did in 2.1.x when I checked.

> Outside of the ACK cases, the other bogus case as I mentioned is for
> clones of real outgoing data packets, used for transmission, the SOCK
> gets charged again for the entire data area when in reality only
> sizeof(struct sk_buff) more memory is being tied up due to the clone.

I think this is bogus. I have a strong memory of _not_ updating the socket
counters at all for cloned skb's, exactly because that would have gotten
the counts wrong. The thing used to set "skb->truesize" to zero for this
reason.

I think. It's been a long time since I worked on that code, I have to
admit.

Linus

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu