Messages in this thread Patch in this message | | | From | Mihai Maruseac <> | Subject | [PATCH] dev: use ifindex hash for dev_seq_ops | Date | Fri, 14 Oct 2011 12:53:37 +0300 |
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Instead of using the dev->next chain and trying to resync at each call to dev_seq_start, use the ifindex, keeping the last index in seq->private field.
Tests revealed the following results for ifconfig > /dev/null * 1000 interfaces: * 0.114s without patch * 0.089s with patch * 3000 interfaces: * 0.489s without patch * 0.110s with patch * 5000 interfaces: * 1.363s without patch * 0.250s with patch * 128000 interfaces (other setup): * ~100s without patch * ~30s with patch
Signed-off-by: Mihai Maruseac <mmaruseac@ixiacom.com> --- net/core/dev.c | 55 ++++++++++++++++++++++++++++++++++--------------------- 1 files changed, 34 insertions(+), 21 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c index 70ecb86..ea24445 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4041,6 +4041,37 @@ static int dev_ifconf(struct net *net, char __user *arg) } #ifdef CONFIG_PROC_FS + +struct dev_iter_state { + struct seq_net_private p; + int ifindex; +}; + +static struct net_device *__dev_seq_next(struct seq_file *seq, loff_t *pos) +{ + struct dev_iter_state *state = seq->private; + struct net *net = seq_file_net(seq); + struct net_device *dev; + loff_t off; + + dev = dev_get_by_index_rcu(net, state->ifindex); + if (likely(dev)) + goto found; + + off = 0; + for_each_netdev_rcu(net, dev) + if (off++ == *pos) { + state->ifindex = dev->ifindex; + goto found; + } + + return NULL; +found: + state->ifindex++; + ++*pos; + return dev; +} + /* * This is invoked by the /proc filesystem handler to display a device * in detail. @@ -4048,33 +4079,15 @@ static int dev_ifconf(struct net *net, char __user *arg) void *dev_seq_start(struct seq_file *seq, loff_t *pos) __acquires(RCU) { - struct net *net = seq_file_net(seq); - loff_t off; - struct net_device *dev; - rcu_read_lock(); if (!*pos) return SEQ_START_TOKEN; - - off = 1; - for_each_netdev_rcu(net, dev) - if (off++ == *pos) - return dev; - - return NULL; + return __dev_seq_next(seq, pos); } void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos) { - struct net_device *dev = v; - - if (v == SEQ_START_TOKEN) - dev = first_net_device_rcu(seq_file_net(seq)); - else - dev = next_net_device_rcu(dev); - - ++*pos; - return dev; + return __dev_seq_next(seq, pos); } void dev_seq_stop(struct seq_file *seq, void *v) @@ -4173,7 +4186,7 @@ static const struct seq_operations dev_seq_ops = { static int dev_seq_open(struct inode *inode, struct file *file) { return seq_open_net(inode, file, &dev_seq_ops, - sizeof(struct seq_net_private)); + sizeof(struct dev_iter_state)); } static const struct file_operations dev_seq_fops = { -- 1.7.4.1
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