On Sun, May 05, 2019 at 10:04:21AM -0700, David Miller wrote:
> From: Al Viro <v...@zeniv.linux.org.uk>
> Date: Thu, 2 May 2019 17:32:23 +0100
>
> > it appears that we might take freeing the socket itself to the
> > RCU-delayed part, along with socket->wq. And doing that has
> > an interesting benefit - the only reason to do two separate
> > allocation disappears.
>
> I'm pretty sure we looked into RCU freeing the socket in the
> past but ended up not doing so.
>
> I think it had to do with the latency in releasing sock related
> objects.
>
> However, I might be confusing "struct socket" with "struct sock"
Erm... the only object with changed release time is the memory
occupied by struct sock_alloc. Currently:
final iput of socket
schedule RCU-delayed kfree() of socket->wq
kfree() of socket
With this change:
final iput of socket
schedule RCU-delayed kfree() of coallocated socket and socket->wq
So it would have to be a workload where tons of sockets are created and
torn down, where RCU-delayed freeing of socket_wq is an inevitable evil,
but freeing struct socket_alloc itself must be done immediately, to
reduce the memory pressure. Or am I misreading you?
