Messages in this thread | | | Date | Wed, 19 Jun 2013 21:07:09 +0300 | From | "Michael S. Tsirkin" <> | Subject | Re: [net-next rfc 1/3] net: avoid high order memory allocation for queues by using flex array |
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On Wed, Jun 19, 2013 at 08:58:31AM -0700, Eric Dumazet wrote: > On Wed, 2013-06-19 at 18:40 +0300, Michael S. Tsirkin wrote: > > > That's a good trick too - vmalloc memory is a bit slower > > on x86 since it's not using a huge page, but that's only > > when we have lots of CPUs/queues... > > > > Short term - how about switching to vmalloc if > 32 queues? > > You do not have to switch "if > 32 queues" > > diff --git a/net/core/dev.c b/net/core/dev.c > index fa007db..473cc9e 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -130,6 +130,7 @@ > #include <linux/cpu_rmap.h> > #include <linux/static_key.h> > #include <linux/hashtable.h> > +#include <linux/vmalloc.h> > > #include "net-sysfs.h" > > @@ -5253,6 +5254,14 @@ static void netdev_init_one_queue(struct net_device *dev, > #endif > } > > +static void netif_free_tx_queues(struct net_device *dev) > +{ > + if (is_vmalloc_addr(dev->_tx)) > + vfree(dev->_tx); > + else > + kfree(dev->_tx); > +} > + > static int netif_alloc_netdev_queues(struct net_device *dev) > { > unsigned int count = dev->num_tx_queues; > @@ -5261,9 +5270,11 @@ static int netif_alloc_netdev_queues(struct net_device *dev) > BUG_ON(count < 1); > > tx = kcalloc(count, sizeof(struct netdev_queue), GFP_KERNEL);
As we have explicit code to recover, maybe set __GFP_NOWARN? If we are out of memory, vzalloc will warn too, we don't need two warnings.
> - if (!tx) > - return -ENOMEM; > - > + if (!tx) { > + tx = vzalloc(count * sizeof(struct netdev_queue)); > + if (!tx) > + return -ENOMEM; > + } > dev->_tx = tx; > > netdev_for_each_tx_queue(dev, netdev_init_one_queue, NULL); > @@ -5811,7 +5822,7 @@ free_all: > > free_pcpu: > free_percpu(dev->pcpu_refcnt); > - kfree(dev->_tx); > + netif_free_tx_queues(dev); > #ifdef CONFIG_RPS > kfree(dev->_rx); > #endif > @@ -5836,7 +5847,7 @@ void free_netdev(struct net_device *dev) > > release_net(dev_net(dev)); > > - kfree(dev->_tx); > + netif_free_tx_queues(dev); > #ifdef CONFIG_RPS > kfree(dev->_rx); > #endif >
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