Re: [PATCH] rxrpc_find_service_conn_rcu: use read_seqbegin() rather than read_seqbegin_or_lock()

From: Oleg Nesterov
Date: Wed Nov 01 2023 - 18:17:56 EST


On 11/01, David Howells wrote:
>
> However, I think just changing all of these to always-lockless isn't
> necessarily the most optimal way.

Yes, but so far I am trying to change the users which never take the
lock for writing, so this patch doesn't change the current behaviour.

> I wonder if struct seqlock would make more sense with an rwlock rather than a
> spinlock. As it is, it does an exclusive spinlock for the readpath which is
> kind of overkill.

Heh. Please see

[PATCH 4/5] seqlock: introduce read_seqcount_begin_or_lock() and friends
https://lore.kernel.org/all/20230913155005.GA26252@xxxxxxxxxx/

I am going to return to this later.

Oleg.