| Message ID | 1421337658.11734.76.camel@edumazet-glaptop2.roam.corp.google.com |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thursday, 15. January 2015 08:00:58 Eric Dumazet wrote: > Please apply this patch, and try to lower > /proc/sys/net/core/gro_max_frags and see if this makes a difference > (leaving GRO enabled) > > (start with 7 and increase it, limit being 17) Patch applied to 3.19-rc4+. Results: 7: hang 8: hang 9: hang 10: hang 11: hang 12: hang 13: hang 14: hang 15: hang 16: hang 17: hang for the sake of completeness: 1: hang 2: hang 3: hang 4: hang 5: hang 6: hang Regarding the test procedure: I stopped the download script on the client, changed gro_max_frags and started the download again. No cable unplugging / reboot of the box in between. Just mentioning it to make sure it somehow does not affect what we actually wanted to test. Additional tests have been done with gro_max_frags 1, 7 and 17: - stop networking + unload e1000e -> restart -> download: hang One thing I can say from the testing: The more I increase gro_max_frags, the longer it takes to trigger it. I tried each setting below three times. A value of 17 is really noticeable. 1: 3-8 seconds till hang 7: 7-10 seconds till hang 17: 23-26 seconds till hang Thomas -- 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
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 642d426a668f8ac94daf334c00117f96789f3990..817aee05a1b0623e5752beb0952a6fe6d66e583f 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3400,6 +3400,7 @@ extern int netdev_max_backlog; extern int netdev_tstamp_prequeue; extern int weight_p; extern int bpf_jit_enable; +extern int sysctl_gro_max_frags; bool netdev_has_upper_dev(struct net_device *dev, struct net_device *upper_dev); struct net_device *netdev_upper_get_next_dev_rcu(struct net_device *dev, diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 56db472e9b864e805e0ab36dd73a0404d2fc66d5..c2c2e7e53014617c5da574f2eb8a2889ed743719 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3197,6 +3197,8 @@ err: } EXPORT_SYMBOL_GPL(skb_segment); +int sysctl_gro_max_frags = MAX_SKB_FRAGS; + int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) { struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb); @@ -3219,8 +3221,8 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) int i = skbinfo->nr_frags; int nr_frags = pinfo->nr_frags + i; - if (nr_frags > MAX_SKB_FRAGS) - goto merge; + if (nr_frags > sysctl_gro_max_frags) + return -E2BIG; offset -= headlen; pinfo->nr_frags = nr_frags; @@ -3252,8 +3254,8 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) unsigned int first_size = headlen - offset; unsigned int first_offset; - if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS) - goto merge; + if (nr_frags + 1 + skbinfo->nr_frags > sysctl_gro_max_frags) + return -E2BIG; first_offset = skb->data - (unsigned char *)page_address(page) + diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 31baba2a71ce15e49450f69dae81e7d3be1ff3f2..de73d51381bf8acd0aedeb859ed961468441014a 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -278,6 +278,13 @@ static struct ctl_table net_core_table[] = { .proc_handler = proc_dointvec }, { + .procname = "gro_max_frags", + .data = &sysctl_gro_max_frags, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec + }, + { .procname = "netdev_rss_key", .data = &netdev_rss_key, .maxlen = sizeof(int),