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| author | Jason Wang <jasowang@redhat.com> | 2013-01-23 03:59:12 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-01-23 13:47:06 -0500 |
| commit | edfb6a148ce62e5e19354a1dcd9a34e00815c2a1 (patch) | |
| tree | 839be5ca970b47e5b5fa38c9df3e672732ef6987 /drivers/net/tun.c | |
| parent | 844e88f04410cc4e85615db519c1d44089333c4f (diff) | |
| download | linux-edfb6a148ce62e5e19354a1dcd9a34e00815c2a1.tar.gz linux-edfb6a148ce62e5e19354a1dcd9a34e00815c2a1.tar.bz2 linux-edfb6a148ce62e5e19354a1dcd9a34e00815c2a1.zip | |
tuntap: reduce memory using of queues
A MAX_TAP_QUEUES(1024) queues of tuntap device is always allocated
unconditionally even userspace only requires a single queue device. This is
unnecessary and will lead a very high order of page allocation when has a high
possibility to fail. Solving this by creating a one queue net device when
userspace only use one queue and also reduce MAX_TAP_QUEUES to
DEFAULT_MAX_NUM_RSS_QUEUES which can guarantee the success of
the allocation.
Reported-by: Dirk Hohndel <dirk@hohndel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index c81680dc10eb..8939d2117de2 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -109,11 +109,10 @@ struct tap_filter { unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN]; }; -/* 1024 is probably a high enough limit: modern hypervisors seem to support on - * the order of 100-200 CPUs so this leaves us some breathing space if we want - * to match a queue per guest CPU. - */ -#define MAX_TAP_QUEUES 1024 +/* DEFAULT_MAX_NUM_RSS_QUEUES were choosed to let the rx/tx queues allocated for + * the netdevice to be fit in one page. So we can make sure the success of + * memory allocation. TODO: increase the limit. */ +#define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES #define TUN_FLOW_EXPIRE (3 * HZ) @@ -1583,6 +1582,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) else { char *name; unsigned long flags = 0; + int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? + MAX_TAP_QUEUES : 1; if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; @@ -1606,8 +1607,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) name = ifr->ifr_name; dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, - tun_setup, - MAX_TAP_QUEUES, MAX_TAP_QUEUES); + tun_setup, queues, queues); + if (!dev) return -ENOMEM; |