From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C9CEC77B6F for ; Thu, 13 Apr 2023 12:01:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229854AbjDMMBj (ORCPT ); Thu, 13 Apr 2023 08:01:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229480AbjDMMBf (ORCPT ); Thu, 13 Apr 2023 08:01:35 -0400 Received: from mg.ssi.bg (mg.ssi.bg [193.238.174.37]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3A98E0; Thu, 13 Apr 2023 05:01:33 -0700 (PDT) Received: from mg.ssi.bg (localhost [127.0.0.1]) by mg.bb.i.ssi.bg (Proxmox) with ESMTP id 15BDAD636; Thu, 13 Apr 2023 14:49:22 +0300 (EEST) Received: from ink.ssi.bg (ink.ssi.bg [193.238.174.40]) by mg.bb.i.ssi.bg (Proxmox) with ESMTPS id F37ABD632; Thu, 13 Apr 2023 14:49:21 +0300 (EEST) Received: from ja.ssi.bg (unknown [178.16.129.10]) by ink.ssi.bg (Postfix) with ESMTPS id 8D15F3C0322; Thu, 13 Apr 2023 14:49:14 +0300 (EEST) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by ja.ssi.bg (8.17.1/8.16.1) with ESMTP id 33DBnCGp027072; Thu, 13 Apr 2023 14:49:13 +0300 Date: Thu, 13 Apr 2023 14:49:12 +0300 (EEST) From: Julian Anastasov To: Abhijeet Rastogi cc: Simon Horman , Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, lvs-devel@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ipvs: change ip_vs_conn_tab_bits range to [8,31] In-Reply-To: <20230412-increase_ipvs_conn_tab_bits-v1-1-60a4f9f4c8f2@gmail.com> Message-ID: References: <20230412-increase_ipvs_conn_tab_bits-v1-1-60a4f9f4c8f2@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Wed, 12 Apr 2023, Abhijeet Rastogi via B4 Relay wrote: > From: Abhijeet Rastogi > > Current range [8, 20] is set purely due to historical reasons > because at the time, ~1M (2^20) was considered sufficient. > > Previous change regarding this limit is here. > > Link: https://lore.kernel.org/all/86eabeb9dd62aebf1e2533926fdd13fed48bab1f.1631289960.git.aclaudi@redhat.com/T/#u > > Signed-off-by: Abhijeet Rastogi > --- > The conversation for this started at: > > https://www.spinics.net/lists/netfilter/msg60995.html > > The upper limit for algo is any bit size less than 32, so this > change will allow us to set bit size > 20. Today, it is common to have > RAM available to handle greater than 2^20 connections per-host. This is not a limit of number of connections. I prefer not to allow value above 24 without adding checks for the available memory, this more concern for 32-bit. Blindly allocating 2^20 (1048576 pointers which is 8MB) should not cause OOM but selecting large value and then using this kernel on boxes with less memory is dangerous. > Distros like RHEL already have higher limits set. > --- > net/netfilter/ipvs/Kconfig | 4 ++-- > net/netfilter/ipvs/ip_vs_conn.c | 4 ++-- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig > index 271da8447b29..3e3371f8c0f9 100644 > --- a/net/netfilter/ipvs/Kconfig > +++ b/net/netfilter/ipvs/Kconfig > @@ -44,7 +44,7 @@ config IP_VS_DEBUG > > config IP_VS_TAB_BITS > int "IPVS connection table size (the Nth power of 2)" > - range 8 20 > + range 8 31 > default 12 > help > The IPVS connection hash table uses the chaining scheme to handle > @@ -54,7 +54,7 @@ config IP_VS_TAB_BITS > > Note the table size must be power of 2. The table size will be the > value of 2 to the your input number power. The number to choose is > - from 8 to 20, the default number is 12, which means the table size > + from 8 to 31, the default number is 12, which means the table size > is 4096. Don't input the number too small, otherwise you will lose > performance on it. You can adapt the table size yourself, according > to your virtual server application. It is good to set the table size > diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c > index 13534e02346c..bc0fe1a698d4 100644 > --- a/net/netfilter/ipvs/ip_vs_conn.c > +++ b/net/netfilter/ipvs/ip_vs_conn.c > @@ -1484,8 +1484,8 @@ int __init ip_vs_conn_init(void) > int idx; > > /* Compute size and mask */ > - if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 20) { > - pr_info("conn_tab_bits not in [8, 20]. Using default value\n"); > + if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 31) { > + pr_info("conn_tab_bits not in [8, 31]. Using default value\n"); > ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS; > } > ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits; > > --- > base-commit: 09a9639e56c01c7a00d6c0ca63f4c7c41abe075d > change-id: 20230412-increase_ipvs_conn_tab_bits-4322c90da216 > > Best regards, > -- > Abhijeet Rastogi Regards -- Julian Anastasov