From: "Michael S. Tsirkin" <mst@redhat•com>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: Jason Wang <jasowang@redhat•com>,
davem@davemloft•net, hkchu@google•com,
netdev <netdev@vger•kernel.org>,
dwmw2@infradead•org
Subject: Re: [PATCH net-next] net: allow large number of tx queues
Date: Thu, 20 Jun 2013 11:35:30 +0300 [thread overview]
Message-ID: <20130620083530.GA23909@redhat.com> (raw)
In-Reply-To: <1371716151.3252.390.camel@edumazet-glaptop>
On Thu, Jun 20, 2013 at 01:15:51AM -0700, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google•com>
>
> On Wed, 2013-06-19 at 21:07 +0300, Michael S. Tsirkin wrote:
>
> > 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.
>
> Yes, that's absolutely the right thing to do.
>
> Its yet not clear this patch is really needed, but here it is.
>
> Thanks
>
> [PATCH net-next] net: allow large number of tx queues
>
> netif_alloc_netdev_queues() uses kcalloc() to allocate memory
> for the "struct netdev_queue *_tx" array.
>
> For large number of tx queues, kcalloc() might fail, so this
> patch does a fallback to vzalloc().
>
> As vmalloc() adds overhead on a critical network path, add __GFP_REPEAT
> to kzalloc() flags to do this fallback only when really needed.
>
> Signed-off-by: Eric Dumazet <edumazet@google•com>
FWIW
Acked-by: Michael S. Tsirkin <mst@redhat•com>
This makes it possible to go up to 1K queues which should
be enough, so we can revert the first chunk in
edfb6a148ce62e5e19354a1dcd9a34e00815c2a1.
> ---
> net/core/dev.c | 26 +++++++++++++++++++-------
> 1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index fa007db..722f633 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"
>
> @@ -5253,17 +5254,28 @@ 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;
> struct netdev_queue *tx;
> + size_t sz = count * sizeof(*tx);
>
> - BUG_ON(count < 1);
> -
> - tx = kcalloc(count, sizeof(struct netdev_queue), GFP_KERNEL);
> - if (!tx)
> - return -ENOMEM;
> + BUG_ON(count < 1 || count > 0xffff);
>
> + tx = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
> + if (!tx) {
> + tx = vzalloc(sz);
> + if (!tx)
> + return -ENOMEM;
> + }
> dev->_tx = tx;
>
> netdev_for_each_tx_queue(dev, netdev_init_one_queue, NULL);
> @@ -5811,7 +5823,7 @@ 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 +5848,7 @@ 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
>
next prev parent reply other threads:[~2013-06-20 8:35 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-19 5:40 [net-next rfc 0/3] increase the limit of tuntap queues Jason Wang
2013-06-19 5:40 ` [net-next rfc 1/3] net: avoid high order memory allocation for queues by using flex array Jason Wang
2013-06-19 6:31 ` Eric Dumazet
2013-06-19 7:14 ` Jason Wang
2013-06-19 9:11 ` Michael S. Tsirkin
2013-06-19 9:56 ` Eric Dumazet
2013-06-19 12:22 ` Michael S. Tsirkin
2013-06-19 15:40 ` Michael S. Tsirkin
2013-06-19 15:58 ` Eric Dumazet
2013-06-19 16:06 ` David Laight
2013-06-19 16:28 ` Eric Dumazet
2013-06-19 18:07 ` Michael S. Tsirkin
2013-06-20 8:15 ` [PATCH net-next] net: allow large number of tx queues Eric Dumazet
2013-06-20 8:35 ` Michael S. Tsirkin [this message]
2013-06-21 6:41 ` Jason Wang
2013-06-21 7:12 ` Eric Dumazet
2013-06-23 10:29 ` Michael S. Tsirkin
2013-06-24 6:57 ` David Miller
2013-06-20 5:14 ` [net-next rfc 1/3] net: avoid high order memory allocation for queues by using flex array Jason Wang
2013-06-20 6:05 ` Eric Dumazet
2013-06-19 5:40 ` [net-next rfc 2/3] tuntap: reduce the size of tun_struct " Jason Wang
2013-06-19 5:40 ` [net-next rfc 3/3] tuntap: increase the max queues to 16 Jason Wang
2013-06-19 6:34 ` Eric Dumazet
2013-06-19 7:15 ` Jason Wang
2013-06-19 19:16 ` Jerry Chu
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