| Message ID | alpine.DEB.2.02.1408250823440.31745@tomh.mtv.corp.google.com |
|---|---|
| State | Deferred, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Tom Herbert <therbert@google.com> Date: Mon, 25 Aug 2014 08:27:56 -0700 (PDT) > This patch adds netdev_tx_avail_queue and netdev_avail_queue which are > used to report number of bytes available in transmit queues per BQL. The > functions call dql_avail which returns BQL limit minus number of > inflight bytes. These functions can be called without txlock, for > instance to ascertain how much data should be dequeued from a qdisc in > a batch. When called without the tx_lock, the result is technically a > hint, subsequently when the tx_lock is done for a transmit it is > possible the availability has changed (for example a transmit > completion may have freed up more space in the queue or changed the > limit). > > Signed-off-by: Tom Herbert <therbert@google.com> Ok this looks fine, but could you please resubmit this alongside the first use case? 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
On Mon, Aug 25, 2014 at 5:33 PM, David Miller <davem@davemloft.net> wrote: > From: Tom Herbert <therbert@google.com> > Date: Mon, 25 Aug 2014 08:27:56 -0700 (PDT) > >> This patch adds netdev_tx_avail_queue and netdev_avail_queue which are >> used to report number of bytes available in transmit queues per BQL. The >> functions call dql_avail which returns BQL limit minus number of >> inflight bytes. These functions can be called without txlock, for >> instance to ascertain how much data should be dequeued from a qdisc in >> a batch. When called without the tx_lock, the result is technically a >> hint, subsequently when the tx_lock is done for a transmit it is >> possible the availability has changed (for example a transmit >> completion may have freed up more space in the queue or changed the >> limit). >> >> Signed-off-by: Tom Herbert <therbert@google.com> > > Ok this looks fine, but could you please resubmit this alongside > the first use case? > It should be called when determining the best size for a transmit batch, e.g. how many bytes to dequeue from qdisc on wakeup. > 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
On Mon, 25 Aug 2014 08:27:56 -0700 (PDT) Tom Herbert <therbert@google.com> wrote: > This patch adds netdev_tx_avail_queue and netdev_avail_queue which are > used to report number of bytes available in transmit queues per BQL. The > functions call dql_avail which returns BQL limit minus number of > inflight bytes. These functions can be called without txlock, for > instance to ascertain how much data should be dequeued from a qdisc in > a batch. When called without the tx_lock, the result is technically a > hint, subsequently when the tx_lock is done for a transmit it is > possible the availability has changed (for example a transmit > completion may have freed up more space in the queue or changed the > limit). > > Signed-off-by: Tom Herbert <therbert@google.com> > --- > include/linux/netdevice.h | 28 ++++++++++++++++++++++++++-- > 1 file changed, 26 insertions(+), 2 deletions(-) > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index 0fac884..bdf6c85 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -2544,6 +2544,30 @@ static inline void netdev_completed_queue(struct net_device *dev, > netdev_tx_completed_queue(netdev_get_tx_queue(dev, 0), pkts, bytes); > } > > +static inline int netdev_tx_avail_queue(struct netdev_queue *dev_queue) > +{ > +#ifdef CONFIG_BQL > + return dql_avail(&dev_queue->dql); > +#else > + return DQL_MAX_LIMIT; > +#endif > +} > + > +/** > + * netdev_avail_queue - report how much space is availble for xmit > + * @dev: network device > + * > + * Report the amount of space available in the TX queue in terms of > + * number of bytes. This returns the number of bytes avaiable per > + * DQL. This function may be called without taking the txlock on > + * the device, however in that case the result should be taken as > + * a (strong) hint. > + */ > +static inline int netdev_avail_queue(struct net_device *dev) > +{ > + return netdev_tx_avail_queue(netdev_get_tx_queue(dev, 0)); > +} > + How can this work, when you are always passing 0 to: netdev_get_tx_queue(dev, 0) ???
On Wed, 2014-09-03 at 15:20 +0200, Jesper Dangaard Brouer wrote: > On Mon, 25 Aug 2014 08:27:56 -0700 (PDT) > Tom Herbert <therbert@google.com> wrote: > > > This patch adds netdev_tx_avail_queue and netdev_avail_queue which are > > used to report number of bytes available in transmit queues per BQL. The > > functions call dql_avail which returns BQL limit minus number of > > inflight bytes. These functions can be called without txlock, for > > instance to ascertain how much data should be dequeued from a qdisc in > > a batch. When called without the tx_lock, the result is technically a > > hint, subsequently when the tx_lock is done for a transmit it is > > possible the availability has changed (for example a transmit > > completion may have freed up more space in the queue or changed the > > limit). > > > > Signed-off-by: Tom Herbert <therbert@google.com> > > --- > > include/linux/netdevice.h | 28 ++++++++++++++++++++++++++-- > > 1 file changed, 26 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > > index 0fac884..bdf6c85 100644 > > --- a/include/linux/netdevice.h > > +++ b/include/linux/netdevice.h > > @@ -2544,6 +2544,30 @@ static inline void netdev_completed_queue(struct net_device *dev, > > netdev_tx_completed_queue(netdev_get_tx_queue(dev, 0), pkts, bytes); > > } > > > > +static inline int netdev_tx_avail_queue(struct netdev_queue *dev_queue) > > +{ > > +#ifdef CONFIG_BQL > > + return dql_avail(&dev_queue->dql); > > +#else > > + return DQL_MAX_LIMIT; > > +#endif > > +} > > + > > +/** > > + * netdev_avail_queue - report how much space is availble for xmit > > + * @dev: network device > > + * > > + * Report the amount of space available in the TX queue in terms of > > + * number of bytes. This returns the number of bytes avaiable per > > + * DQL. This function may be called without taking the txlock on > > + * the device, however in that case the result should be taken as > > + * a (strong) hint. > > + */ > > +static inline int netdev_avail_queue(struct net_device *dev) > > +{ > > + return netdev_tx_avail_queue(netdev_get_tx_queue(dev, 0)); > > +} > > + > > How can this work, when you are always passing 0 to: netdev_get_tx_queue(dev, 0) > ??? > This is the helper for drivers having a single TX queue. -- 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
On Wed, 03 Sep 2014 06:41:57 -0700 Eric Dumazet <eric.dumazet@gmail.com> wrote: > On Wed, 2014-09-03 at 15:20 +0200, Jesper Dangaard Brouer wrote: > > On Mon, 25 Aug 2014 08:27:56 -0700 (PDT) > > Tom Herbert <therbert@google.com> wrote: > > > > > This patch adds netdev_tx_avail_queue and netdev_avail_queue which are > > > used to report number of bytes available in transmit queues per BQL. The > > > functions call dql_avail which returns BQL limit minus number of > > > inflight bytes. These functions can be called without txlock, for > > > instance to ascertain how much data should be dequeued from a qdisc in > > > a batch. When called without the tx_lock, the result is technically a > > > hint, subsequently when the tx_lock is done for a transmit it is > > > possible the availability has changed (for example a transmit > > > completion may have freed up more space in the queue or changed the > > > limit). > > > > > > Signed-off-by: Tom Herbert <therbert@google.com> > > > --- > > > include/linux/netdevice.h | 28 ++++++++++++++++++++++++++-- > > > 1 file changed, 26 insertions(+), 2 deletions(-) > > > > > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > > > index 0fac884..bdf6c85 100644 > > > --- a/include/linux/netdevice.h > > > +++ b/include/linux/netdevice.h > > > @@ -2544,6 +2544,30 @@ static inline void netdev_completed_queue(struct net_device *dev, > > > netdev_tx_completed_queue(netdev_get_tx_queue(dev, 0), pkts, bytes); > > > } > > > > > > +static inline int netdev_tx_avail_queue(struct netdev_queue *dev_queue) > > > +{ > > > +#ifdef CONFIG_BQL > > > + return dql_avail(&dev_queue->dql); > > > +#else > > > + return DQL_MAX_LIMIT; > > > +#endif > > > +} > > > + > > > +/** > > > + * netdev_avail_queue - report how much space is availble for xmit > > > + * @dev: network device > > > + * > > > + * Report the amount of space available in the TX queue in terms of > > > + * number of bytes. This returns the number of bytes avaiable per > > > + * DQL. This function may be called without taking the txlock on > > > + * the device, however in that case the result should be taken as > > > + * a (strong) hint. > > > + */ > > > +static inline int netdev_avail_queue(struct net_device *dev) > > > +{ > > > + return netdev_tx_avail_queue(netdev_get_tx_queue(dev, 0)); > > > +} > > > + > > > > How can this work, when you are always passing 0 to: netdev_get_tx_queue(dev, 0) > > ??? > > > > This is the helper for drivers having a single TX queue. Okay, so I should use: bytelimit = netdev_tx_avail_queue(txq);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 0fac884..bdf6c85 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2544,6 +2544,30 @@ static inline void netdev_completed_queue(struct net_device *dev, netdev_tx_completed_queue(netdev_get_tx_queue(dev, 0), pkts, bytes); } +static inline int netdev_tx_avail_queue(struct netdev_queue *dev_queue) +{ +#ifdef CONFIG_BQL + return dql_avail(&dev_queue->dql); +#else + return DQL_MAX_LIMIT; +#endif +} + +/** + * netdev_avail_queue - report how much space is availble for xmit + * @dev: network device + * + * Report the amount of space available in the TX queue in terms of + * number of bytes. This returns the number of bytes avaiable per + * DQL. This function may be called without taking the txlock on + * the device, however in that case the result should be taken as + * a (strong) hint. + */ +static inline int netdev_avail_queue(struct net_device *dev) +{ + return netdev_tx_avail_queue(netdev_get_tx_queue(dev, 0)); +} + static inline void netdev_tx_reset_queue(struct netdev_queue *q) { #ifdef CONFIG_BQL @@ -2559,9 +2583,9 @@ static inline void netdev_tx_reset_queue(struct netdev_queue *q) * Reset the bytes and packet count of a network device and clear the * software flow control OFF bit for this network device */ -static inline void netdev_reset_queue(struct net_device *dev_queue) +static inline void netdev_reset_queue(struct net_device *dev) { - netdev_tx_reset_queue(netdev_get_tx_queue(dev_queue, 0)); + netdev_tx_reset_queue(netdev_get_tx_queue(dev, 0)); } /**
This patch adds netdev_tx_avail_queue and netdev_avail_queue which are used to report number of bytes available in transmit queues per BQL. The functions call dql_avail which returns BQL limit minus number of inflight bytes. These functions can be called without txlock, for instance to ascertain how much data should be dequeued from a qdisc in a batch. When called without the tx_lock, the result is technically a hint, subsequently when the tx_lock is done for a transmit it is possible the availability has changed (for example a transmit completion may have freed up more space in the queue or changed the limit). Signed-off-by: Tom Herbert <therbert@google.com> --- include/linux/netdevice.h | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-)