On Thu, 2018-02-01 at 20:34 +0800, Tonghao Zhang wrote:
> Hi Eric
> One question for you, In the patch ef547f2ac16 ("tcp: remove
> max_qlen_log"), why we compared the length of req sock queue with
> sk_max_ack_backlog. If we remove the max_qlen_log, we should check the
> length of req sock queue with tcp_max_syn_backlog, right ?
>
> With this patch, the option "/proc/sys/net/ipv4/tcp_max_syn_backlog"
> will be unsed anymore, right ?
Not right.
Please "git grep -n sysctl_max_syn_backlog" to convince it is still
used.
>
> I hope we should
> 1. Add a variate in sock struct, such as sk_max_syn_backlog. Then req
> sock queue and accept sock queue can control their max value. When we
> create the sock, we can store the tcp_max_syn_backlog value to
> sk_max_syn_backlog.
>
There is a single /proc/sys/net/ipv4/tcp_max_syn_backlog value shared
by all sockets of a given network namespace.
But you can have thousands of TCP listeners, each of them having a
distinct listen() backlog
> 2. Update the backlog, we can update it via ioctl.
No need to add an ugly ioctl.
Simply call listen() again with another backlog value.
