On 24 Apr 2024, at 6:41, Chen Hanxiao wrote:
> add an empty list check, so we can get rid of some useless
> list iterate or spin locks.
>
> Signed-off-by: Chen Hanxiao <chenhx.fnst@xxxxxxxxxxx>
> ---
> net/sunrpc/clnt.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index 28f3749f6dc6..749317587bb3 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -3345,8 +3345,13 @@ void rpc_show_tasks(struct net *net)
> int header = 0;
> struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
>
> + if (list_empty(&sn->all_clients))
> + return;
> +
> spin_lock(&sn->rpc_client_lock);
> list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
> + if (list_empty(&clnt->cl_tasks))
> + continue;
> spin_lock(&clnt->cl_lock);
> list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
> if (!header) {
> --
> 2.39.1
Why optimize this? Can you show the locks are contended? Its probably
fine, but using list_empty outside of the lock has a bad smell to me.
Ben
