From patchwork Tue Jan 18 20:46:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 12716882 X-Patchwork-Delegate: kuba@kernel.org 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 42D00C433EF for ; Tue, 18 Jan 2022 20:46:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245114AbiARUqz (ORCPT ); Tue, 18 Jan 2022 15:46:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233264AbiARUqy (ORCPT ); Tue, 18 Jan 2022 15:46:54 -0500 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69E30C061574 for ; Tue, 18 Jan 2022 12:46:54 -0800 (PST) Received: by mail-pf1-x429.google.com with SMTP id i17so415884pfk.11 for ; Tue, 18 Jan 2022 12:46:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VdJo11ympIHswpxStbh7x3K+g2KKhczLwPvc0Taj6fI=; b=i7EFSxHkm/heHuY5j54deWHh4AxnOsiUtFqPxc2dWRd1BKAi7FZ8LnAXnOTNTbaz6L h5meq95yG5o6al5kzCn5MeHDFO8qzz/mxrDuW+TK5PZow7JdO2Dp4nA1GJKl/rQ7N928 aclAFPdHV8uivL+mUPwp890nzmVrhwVz/gQKeZZlTBLw2M2LSjYoV/D4r9QOKnl6Mj0R srVjIVli9kYz2nvO4SBhi/L+IZ8busvZ1yaaexA/alt/iCEGak+a24vWpXcCnIpVg63t JZ1XQCsoDYEE3lt8M5xEsHOGokVVILTR73kws5j4EXbWCIxcL8PKSaLiCBgS2ZyLHpEw ygfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=VdJo11ympIHswpxStbh7x3K+g2KKhczLwPvc0Taj6fI=; b=BXgIai/PfIbvGyJjFLfJgP0leTymqqsWZK2IH6cgoiKpYBc8FJtm+2+Z+GaI36rSA/ mVsGzNdiLlPPZLV5PWTuqkct6W6Y90TxI6KGFzQueM3ztp+/505cGKZqwsyi8S0E/grg rky7C0+q3KqX00BGqvgwQqeR5BhkRLejr+IBRJGn+FHWFADBi3sDFW+XNA4ofBls6ZzC y2Y7cPuOyevH4UMa3h7pYM+64OnAt/Vh6nzvVjKlyaE8MpMFMvY6yDVwk7aAGs1kHb6k UIumwnUkJ6zrz0MMXwRwa4mJgew1dkrNjIOII3xdyr5ju60tFvgP7jBrtqd9o9ciBuP0 yn5Q== X-Gm-Message-State: AOAM532K9TQpB4L1ubNlLK+YxmzW+3+fnlo7BFOER3XitA9pQvAVWjwc lwJMmMGcPlnSX8NHzLCHvqU= X-Google-Smtp-Source: ABdhPJxMTE6ll5Sz8lRvXG/k1O3S8v2ttFavA6H6KFc9YwZTCa7swsYc8xS6krvsWNKrF36GRPR00Q== X-Received: by 2002:a63:6909:: with SMTP id e9mr13527776pgc.240.1642538813962; Tue, 18 Jan 2022 12:46:53 -0800 (PST) Received: from edumazet1.svl.corp.google.com ([2620:15c:2c4:201:a634:e286:f865:178a]) by smtp.gmail.com with ESMTPSA id x29sm18908915pfh.175.2022.01.18.12.46.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Jan 2022 12:46:53 -0800 (PST) From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski Cc: David Ahern , netdev , Eric Dumazet , Eric Dumazet Subject: [PATCH net 2/2] ipv4: add net_hash_mix() dispersion to fib_info_laddrhash keys Date: Tue, 18 Jan 2022 12:46:46 -0800 Message-Id: <20220118204646.3977185-3-eric.dumazet@gmail.com> X-Mailer: git-send-email 2.34.1.703.g22d0c6ccf7-goog In-Reply-To: <20220118204646.3977185-1-eric.dumazet@gmail.com> References: <20220118204646.3977185-1-eric.dumazet@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Eric Dumazet net/ipv4/fib_semantics.c uses a hash table (fib_info_laddrhash) in which fib_sync_down_addr() can locate fib_info based on IPv4 local address. This hash table is resized based on total number of hashed fib_info, but the hash function is only using the local address. For hosts having many active network namespaces, all fib_info for loopback devices (IPv4 address 127.0.0.1) are hashed into a single bucket, making netns dismantles very slow. Signed-off-by: Eric Dumazet --- net/ipv4/fib_semantics.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index 9813949da10493de36b9db797b6a5d94fd9bd3b1..7971889fc0fe3690e47931c39e6a8f8e0fb1d31f 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -52,6 +52,7 @@ static DEFINE_SPINLOCK(fib_info_lock); static struct hlist_head *fib_info_hash; static struct hlist_head *fib_info_laddrhash; static unsigned int fib_info_hash_size; +static unsigned int fib_info_hash_bits; static unsigned int fib_info_cnt; #define DEVINDEX_HASHBITS 8 @@ -1247,13 +1248,9 @@ int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, return err; } -static inline unsigned int fib_laddr_hashfn(__be32 val) +static inline unsigned int fib_laddr_hashfn(const struct net *net, __be32 val) { - unsigned int mask = (fib_info_hash_size - 1); - - return ((__force u32)val ^ - ((__force u32)val >> 7) ^ - ((__force u32)val >> 14)) & mask; + return hash_32(net_hash_mix(net) ^ (__force u32)val, fib_info_hash_bits); } static struct hlist_head *fib_info_hash_alloc(int bytes) @@ -1289,6 +1286,7 @@ static void fib_info_hash_move(struct hlist_head *new_info_hash, old_info_hash = fib_info_hash; old_laddrhash = fib_info_laddrhash; fib_info_hash_size = new_size; + fib_info_hash_bits = ilog2(new_size); for (i = 0; i < old_size; i++) { struct hlist_head *head = &fib_info_hash[i]; @@ -1315,7 +1313,7 @@ static void fib_info_hash_move(struct hlist_head *new_info_hash, struct hlist_head *ldest; unsigned int new_hash; - new_hash = fib_laddr_hashfn(fi->fib_prefsrc); + new_hash = fib_laddr_hashfn(fi->fib_net, fi->fib_prefsrc); ldest = &new_laddrhash[new_hash]; hlist_add_head(&fi->fib_lhash, ldest); } @@ -1605,7 +1603,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg, if (fi->fib_prefsrc) { struct hlist_head *head; - head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; + head = &fib_info_laddrhash[fib_laddr_hashfn(net, fi->fib_prefsrc)]; hlist_add_head(&fi->fib_lhash, head); } if (fi->nh) { @@ -1877,16 +1875,16 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, */ int fib_sync_down_addr(struct net_device *dev, __be32 local) { - int ret = 0; - unsigned int hash = fib_laddr_hashfn(local); - struct hlist_head *head = &fib_info_laddrhash[hash]; int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; struct net *net = dev_net(dev); + struct hlist_head *head; struct fib_info *fi; + int ret = 0; if (!fib_info_laddrhash || local == 0) return 0; + head = &fib_info_laddrhash[fib_laddr_hashfn(net, local)]; hlist_for_each_entry(fi, head, fib_lhash) { if (!net_eq(fi->fib_net, net) || fi->fib_tb_id != tb_id)