| Message ID | 20100607132738.GB2730@psychotron.lab.eng.brq.redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, 7 Jun 2010 15:27:39 +0200, Jiri Pirko <jpirko@redhat.com> wrote: > Use call_rcu rather than synchronize_rcu. > > Signed-off-by: Jiri Pirko <jpirko@redhat.com> This looks fine to me, but what is the goal here? The RCU documentation seems to imply that synchronize_rcu() is preferable over call_rcu() when at all possible.
Le lundi 07 juin 2010 à 15:43 +0200, Rémi Denis-Courmont a écrit : > On Mon, 7 Jun 2010 15:27:39 +0200, Jiri Pirko <jpirko@redhat.com> wrote: > > Use call_rcu rather than synchronize_rcu. > > > > Signed-off-by: Jiri Pirko <jpirko@redhat.com> > > This looks fine to me, but what is the goal here? The RCU documentation > seems to imply that synchronize_rcu() is preferable over call_rcu() when at > all possible. > Thats not exactly that. synchronize_rcu() is easier, in respect of memory use. But its drawback is current thread is blocked for several milli seconds. In the end, call_rcu() is more scalable. Acked-by: Eric Dumazet <eric.dumazet@gmail.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Mon, 07 Jun 2010 15:49:43 +0200 > Le lundi 07 juin 2010 à 15:43 +0200, Rémi Denis-Courmont a écrit : >> On Mon, 7 Jun 2010 15:27:39 +0200, Jiri Pirko <jpirko@redhat.com> wrote: >> > Use call_rcu rather than synchronize_rcu. >> > >> > Signed-off-by: Jiri Pirko <jpirko@redhat.com> >> >> This looks fine to me, but what is the goal here? The RCU documentation >> seems to imply that synchronize_rcu() is preferable over call_rcu() when at >> all possible. >> > > Thats not exactly that. > > synchronize_rcu() is easier, in respect of memory use. > But its drawback is current thread is blocked for several milli seconds. > > In the end, call_rcu() is more scalable. > > Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/net/phonet/pn_dev.h b/include/net/phonet/pn_dev.h index d7b989c..2d16783 100644 --- a/include/net/phonet/pn_dev.h +++ b/include/net/phonet/pn_dev.h @@ -34,6 +34,7 @@ struct phonet_device { struct list_head list; struct net_device *netdev; DECLARE_BITMAP(addrs, 64); + struct rcu_head rcu; }; int phonet_device_init(void); diff --git a/net/phonet/pn_dev.c b/net/phonet/pn_dev.c index c33da65..b18e48f 100644 --- a/net/phonet/pn_dev.c +++ b/net/phonet/pn_dev.c @@ -162,6 +162,14 @@ int phonet_address_add(struct net_device *dev, u8 addr) return err; } +static void phonet_device_rcu_free(struct rcu_head *head) +{ + struct phonet_device *pnd; + + pnd = container_of(head, struct phonet_device, rcu); + kfree(pnd); +} + int phonet_address_del(struct net_device *dev, u8 addr) { struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev)); @@ -179,10 +187,9 @@ int phonet_address_del(struct net_device *dev, u8 addr) pnd = NULL; mutex_unlock(&pndevs->lock); - if (pnd) { - synchronize_rcu(); - kfree(pnd); - } + if (pnd) + call_rcu(&pnd->rcu, phonet_device_rcu_free); + return err; }
Use call_rcu rather than synchronize_rcu. Signed-off-by: Jiri Pirko <jpirko@redhat.com> --- include/net/phonet/pn_dev.h | 1 + net/phonet/pn_dev.c | 15 +++++++++++---- 2 files changed, 12 insertions(+), 4 deletions(-)