From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2BCC13FE0; Sat, 13 Jan 2024 09:55:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HkjeP15D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CB0CC433F1; Sat, 13 Jan 2024 09:55:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705139718; bh=EyHr8a1oqK9hMs+vfXx/V541EepNpwnz33AuGxer/8E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HkjeP15Dt7SQ5C4BxL3wranxg2DjcMpxlQjbkJOU51qAUnAalZuAMR7eDJwKdkdoB Dxknmc3gTWClPJhDEJYq66VK321sC4vvfumn4GhW0+bFL9UmNiqXoeMcyAm5IYj6hU j3D46ASDMRpwJ/Ki98t8d78feBMwSmUluqH+k9PE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andrea Mayer , Jon Maxwell , David Ahern , Jakub Kicinski , Suraj Jitindar Singh Subject: [PATCH 4.19 25/25] ipv6: remove max_size check inline with ipv4 Date: Sat, 13 Jan 2024 10:50:06 +0100 Message-ID: <20240113094205.833099566@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240113094205.025407355@linuxfoundation.org> References: <20240113094205.025407355@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jon Maxwell commit af6d10345ca76670c1b7c37799f0d5576ccef277 upstream. In ip6_dst_gc() replace: if (entries > gc_thresh) With: if (entries > ops->gc_thresh) Sending Ipv6 packets in a loop via a raw socket triggers an issue where a route is cloned by ip6_rt_cache_alloc() for each packet sent. This quickly consumes the Ipv6 max_size threshold which defaults to 4096 resulting in these warnings: [1] 99.187805] dst_alloc: 7728 callbacks suppressed [2] Route cache is full: consider increasing sysctl net.ipv6.route.max_size. . . [300] Route cache is full: consider increasing sysctl net.ipv6.route.max_size. When this happens the packet is dropped and sendto() gets a network is unreachable error: remaining pkt 200557 errno 101 remaining pkt 196462 errno 101 . . remaining pkt 126821 errno 101 Implement David Aherns suggestion to remove max_size check seeing that Ipv6 has a GC to manage memory usage. Ipv4 already does not check max_size. Here are some memory comparisons for Ipv4 vs Ipv6 with the patch: Test by running 5 instances of a program that sends UDP packets to a raw socket 5000000 times. Compare Ipv4 and Ipv6 performance with a similar program. Ipv4: Before test: MemFree: 29427108 kB Slab: 237612 kB ip6_dst_cache 1912 2528 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 2881 3990 192 42 2 : tunables 0 0 0 During test: MemFree: 29417608 kB Slab: 247712 kB ip6_dst_cache 1912 2528 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 44394 44394 192 42 2 : tunables 0 0 0 After test: MemFree: 29422308 kB Slab: 238104 kB ip6_dst_cache 1912 2528 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 3048 4116 192 42 2 : tunables 0 0 0 Ipv6 with patch: Errno 101 errors are not observed anymore with the patch. Before test: MemFree: 29422308 kB Slab: 238104 kB ip6_dst_cache 1912 2528 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 3048 4116 192 42 2 : tunables 0 0 0 During Test: MemFree: 29431516 kB Slab: 240940 kB ip6_dst_cache 11980 12064 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 3048 4116 192 42 2 : tunables 0 0 0 After Test: MemFree: 29441816 kB Slab: 238132 kB ip6_dst_cache 1902 2432 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 3048 4116 192 42 2 : tunables 0 0 0 Tested-by: Andrea Mayer Signed-off-by: Jon Maxwell Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230112012532.311021-1-jmaxwell37@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Suraj Jitindar Singh Cc: # 4.19.x Signed-off-by: Greg Kroah-Hartman --- include/net/dst_ops.h | 2 +- net/core/dst.c | 8 ++------ net/ipv6/route.c | 13 +++++-------- 3 files changed, 8 insertions(+), 15 deletions(-) --- a/include/net/dst_ops.h +++ b/include/net/dst_ops.h @@ -16,7 +16,7 @@ struct dst_ops { unsigned short family; unsigned int gc_thresh; - int (*gc)(struct dst_ops *ops); + void (*gc)(struct dst_ops *ops); struct dst_entry * (*check)(struct dst_entry *, __u32 cookie); unsigned int (*default_advmss)(const struct dst_entry *); unsigned int (*mtu)(const struct dst_entry *); --- a/net/core/dst.c +++ b/net/core/dst.c @@ -99,12 +99,8 @@ void *dst_alloc(struct dst_ops *ops, str if (ops->gc && !(flags & DST_NOCOUNT) && - dst_entries_get_fast(ops) > ops->gc_thresh) { - if (ops->gc(ops)) { - pr_notice_ratelimited("Route cache is full: consider increasing sysctl net.ipv6.route.max_size.\n"); - return NULL; - } - } + dst_entries_get_fast(ops) > ops->gc_thresh) + ops->gc(ops); dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC); if (!dst) --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -92,7 +92,7 @@ static struct dst_entry *ip6_negative_ad static void ip6_dst_destroy(struct dst_entry *); static void ip6_dst_ifdown(struct dst_entry *, struct net_device *dev, int how); -static int ip6_dst_gc(struct dst_ops *ops); +static void ip6_dst_gc(struct dst_ops *ops); static int ip6_pkt_discard(struct sk_buff *skb); static int ip6_pkt_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb); @@ -2767,11 +2767,10 @@ out: return dst; } -static int ip6_dst_gc(struct dst_ops *ops) +static void ip6_dst_gc(struct dst_ops *ops) { struct net *net = container_of(ops, struct net, ipv6.ip6_dst_ops); int rt_min_interval = net->ipv6.sysctl.ip6_rt_gc_min_interval; - int rt_max_size = net->ipv6.sysctl.ip6_rt_max_size; int rt_elasticity = net->ipv6.sysctl.ip6_rt_gc_elasticity; int rt_gc_timeout = net->ipv6.sysctl.ip6_rt_gc_timeout; unsigned long rt_last_gc = net->ipv6.ip6_rt_last_gc; @@ -2779,11 +2778,10 @@ static int ip6_dst_gc(struct dst_ops *op int entries; entries = dst_entries_get_fast(ops); - if (entries > rt_max_size) + if (entries > ops->gc_thresh) entries = dst_entries_get_slow(ops); - if (time_after(rt_last_gc + rt_min_interval, jiffies) && - entries <= rt_max_size) + if (time_after(rt_last_gc + rt_min_interval, jiffies)) goto out; fib6_run_gc(atomic_inc_return(&net->ipv6.ip6_rt_gc_expire), net, true); @@ -2793,7 +2791,6 @@ static int ip6_dst_gc(struct dst_ops *op out: val = atomic_read(&net->ipv6.ip6_rt_gc_expire); atomic_set(&net->ipv6.ip6_rt_gc_expire, val - (val >> rt_elasticity)); - return entries > rt_max_size; } static int ip6_convert_metrics(struct net *net, struct fib6_info *rt, @@ -5336,7 +5333,7 @@ static int __net_init ip6_route_net_init #endif net->ipv6.sysctl.flush_delay = 0; - net->ipv6.sysctl.ip6_rt_max_size = 4096; + net->ipv6.sysctl.ip6_rt_max_size = INT_MAX; net->ipv6.sysctl.ip6_rt_gc_min_interval = HZ / 2; net->ipv6.sysctl.ip6_rt_gc_timeout = 60*HZ; net->ipv6.sysctl.ip6_rt_gc_interval = 30*HZ;