On Tue, Jul 04, 2023 at 10:56:08AM +1000, NeilBrown wrote:
> On Tue, 04 Jul 2023, Chuck Lever wrote:
> > From: Chuck Lever <chuck.lever@xxxxxxxxxx>
> >
> > Consumers of sp_lock now all run in process context. We can avoid
> > the overhead of disabling bottom halves when taking this lock.
>
> "now" suggests that something has recently changed so that sp_lock isn't
> taken in bh context. What was that change - I don't see it.
>
> I think svc_data_ready() is called in bh, and that calls
> svc_xprt_enqueue() which take sp_lock to add the xprt to ->sp_sockets.
>
> Is that not still the case?
Darn, I forgot about that one. I'll drop this patch.
> NeilBrown
>
>
> >
> > Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> > ---
> > net/sunrpc/svc_xprt.c | 14 +++++++-------
> > 1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> > index ecbccf0d89b9..8ced7591ce07 100644
> > --- a/net/sunrpc/svc_xprt.c
> > +++ b/net/sunrpc/svc_xprt.c
> > @@ -472,9 +472,9 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
> > pool = svc_pool_for_cpu(xprt->xpt_server);
> >
> > percpu_counter_inc(&pool->sp_sockets_queued);
> > - spin_lock_bh(&pool->sp_lock);
> > + spin_lock(&pool->sp_lock);
> > list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
> > - spin_unlock_bh(&pool->sp_lock);
> > + spin_unlock(&pool->sp_lock);
> >
> > rqstp = svc_pool_wake_idle_thread(xprt->xpt_server, pool);
> > if (!rqstp) {
> > @@ -496,14 +496,14 @@ static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
> > if (list_empty(&pool->sp_sockets))
> > goto out;
> >
> > - spin_lock_bh(&pool->sp_lock);
> > + spin_lock(&pool->sp_lock);
> > if (likely(!list_empty(&pool->sp_sockets))) {
> > xprt = list_first_entry(&pool->sp_sockets,
> > struct svc_xprt, xpt_ready);
> > list_del_init(&xprt->xpt_ready);
> > svc_xprt_get(xprt);
> > }
> > - spin_unlock_bh(&pool->sp_lock);
> > + spin_unlock(&pool->sp_lock);
> > out:
> > return xprt;
> > }
> > @@ -1116,15 +1116,15 @@ static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
> > for (i = 0; i < serv->sv_nrpools; i++) {
> > pool = &serv->sv_pools[i];
> >
> > - spin_lock_bh(&pool->sp_lock);
> > + spin_lock(&pool->sp_lock);
> > list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
> > if (xprt->xpt_net != net)
> > continue;
> > list_del_init(&xprt->xpt_ready);
> > - spin_unlock_bh(&pool->sp_lock);
> > + spin_unlock(&pool->sp_lock);
> > return xprt;
> > }
> > - spin_unlock_bh(&pool->sp_lock);
> > + spin_unlock(&pool->sp_lock);
> > }
> > return NULL;
> > }
> >
> >
> >
>
