From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: iptables/tc: page allocation failures question Date: Sat, 03 Nov 2012 12:34:59 +0100 Message-ID: <1351942499.21634.1640.camel@edumazet-glaptop> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Miroslav Kratochvil Return-path: Received: from mail-ea0-f174.google.com ([209.85.215.174]:42749 "EHLO mail-ea0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751864Ab2KCLfE (ORCPT ); Sat, 3 Nov 2012 07:35:04 -0400 Received: by mail-ea0-f174.google.com with SMTP id c13so1666523eaa.19 for ; Sat, 03 Nov 2012 04:35:03 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Sat, 2012-11-03 at 11:27 +0100, Miroslav Kratochvil wrote: > Hello everyone, > > I've got several linux boxes that do mostly routing and traffic > shaping stuff. The load isn't any dramatic - it's around 100Mbit of > traffic shaping over a HFSC qdisc with ~10k classes/filters. > > Recently I started seeing messages like this in dmesg: > > iptables: page allocation failure: order:9, mode:0xc0d0 > > tc: page allocation failure (....) > > (full messages are attached below) > > I understood that it means the kernel couldn't allocate memory for > execution of given command - it is usually triggered by stuff like 'tc > class add' or 'iptables -A something'. > > The boxes, on the other hand, still have pretty much free memory > (alloc+buffers+cache fill around 400MB of 2 gigs available, swap is > empty). I guess the problem is caused by the fact that the allocation > is constrained by something (like GFP_ATOMIC, or that they can only > allocate lower memory). Is this true? If so, is there some possibility > to avoid such constraint? > > What also worries me is that when the box at some point starts to do > memory allocation failures, I've been unable to make it stop, even if > I delete all qdiscs/iptable entries, clear every cache I know about > and restart most of userspace, which should hopefully free a good > amount of memory, nothing can be added back. > > I'm attaching the dmesg of the failure below. Could anyone provide a > comment on this, or possibly point me to what can cause this behavior? > Is there any better debug output that could clarify this? > > Thanks in advance, > Mirek Kratochvil You apparently load xt_recent module with a big ip_list_tot value (default is 100), and kzalloc() wants an order-9 page (contiguous 2MB of ram), and it fails. I guess following patch should solve your problem diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index 4635c9b..ceebd8b 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -310,6 +311,14 @@ out: return ret; } +static void recent_table_free(void *addr) +{ + if (is_vmalloc_addr(addr)) + vfree(addr); + else + kfree(addr); +} + static int recent_mt_check(const struct xt_mtchk_param *par, const struct xt_recent_mtinfo_v1 *info) { @@ -322,6 +331,7 @@ static int recent_mt_check(const struct xt_mtchk_param *par, #endif unsigned int i; int ret = -EINVAL; + size_t sz; if (unlikely(!hash_rnd_inited)) { get_random_bytes(&hash_rnd, sizeof(hash_rnd)); @@ -360,8 +370,11 @@ static int recent_mt_check(const struct xt_mtchk_param *par, goto out; } - t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size, - GFP_KERNEL); + sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size; + if (sz <= PAGE_SIZE) + t = kzalloc(sz, GFP_KERNEL); + else + t = vzalloc(sz); if (t == NULL) { ret = -ENOMEM; goto out; @@ -377,14 +390,14 @@ static int recent_mt_check(const struct xt_mtchk_param *par, uid = make_kuid(&init_user_ns, ip_list_uid); gid = make_kgid(&init_user_ns, ip_list_gid); if (!uid_valid(uid) || !gid_valid(gid)) { - kfree(t); + recent_table_free(t); ret = -EINVAL; goto out; } pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent, &recent_mt_fops, t); if (pde == NULL) { - kfree(t); + recent_table_free(t); ret = -ENOMEM; goto out; } @@ -434,7 +447,7 @@ static void recent_mt_destroy(const struct xt_mtdtor_param *par) remove_proc_entry(t->name, recent_net->xt_recent); #endif recent_table_flush(t); - kfree(t); + recent_table_free(t); } mutex_unlock(&recent_mutex); }