From patchwork Tue May 7 12:42:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leone Fernando X-Patchwork-Id: 13656800 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-wr1-f65.google.com (mail-wr1-f65.google.com [209.85.221.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6BC04158D9C; Tue, 7 May 2024 12:44:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.65 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715085860; cv=none; b=PNxTrclI+TtC4aJ+eCqctHncLilKAILfC/lc5yq6X+yErLefMOx7al9makha2p51kGg4gsIV47AuKBT7NQR2SARaPri/F8UE3nw3SsUcFhKVXz4GOREkSzDuXrKtMJW8T4c/Nbv9o2oOnU4XGVmWz89RAHO1YBkyF3exOtpx9KQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715085860; c=relaxed/simple; bh=uM5sJnWrOplndwtlhh0T7d3Eeti4vJVik1sqvT2i43A=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=pjIUxWz7Fn7Zg0Ln+kHfWvplmCWlbl37Zam9s2swpGRqDfnzhyGo5A0KrkRN+vvMtqg7UD07MG1Mf6b/RnjhnT7p0glJydN+thhTr9TmBsgL61WKNQxXyVPADQDw9Jq+jAlFTGObkpjSdhStVbbTChgJIJoRR5tAjwFSTVNGTY8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=JV0pymax; arc=none smtp.client-ip=209.85.221.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="JV0pymax" Received: by mail-wr1-f65.google.com with SMTP id ffacd0b85a97d-34db6a29a1eso1996057f8f.1; Tue, 07 May 2024 05:44:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1715085857; x=1715690657; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=lWpqb3t6CANxEDWhaC7kiYcjYm92T0oXtF4rwdCOiDo=; b=JV0pymaxgFKwP2tlaOKWQ2DUoQ9ZW0aRvOM6w1YCEzKbI+LvZXIXf1yP8xQBIqqUZO Hj//BAwgECR3AV1xNSO9+NjLSBKooJnK099P/VTE7BDzV6gmPLT3W0Zy9z7CjWSLk9VJ DFo/Egvkqe4dLUa7KUUegz1uCQAOpxntiURYzsE/eoF1sxlWuHiXcarSQF0VPvw4kzyO x3TFsNpbxlzVxOeeaWJ+Cb/tqoeSwVqrRex36lkbS/aaaYHqDOU3sd1M/tiSShVL2efA rZ85TnVRy7UaobFQakyFPE42Lxrx2WfR8xNj8LXL4LUnF08nPv4En8SlzGRIIO7uMNVV TDZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1715085857; x=1715690657; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=lWpqb3t6CANxEDWhaC7kiYcjYm92T0oXtF4rwdCOiDo=; b=soePD6Ef5kGSQySnRNdAoV8vh4ZYOHHIkKv7A6GR+ro16LPaufpflXNQitUz6VMlal DVeCSMvP8DfCjoSocyo1he1VtBKdYqPFfUMjCJaQ92uCKP+r17fTFJlgaYH6XxUXlG6a hQRroIQCZ8C+OvnY2vipRd5VgRdHTxVnvvfN5LmoqokRp3jy0a+dxJpU/ob8snLxQBd9 /Z5Xp6EcHKoJl78I30541JSdBt5VWEy5FzWNspFCCnEIUTv7JGVEaS4XfgL/RBfU0Xtd S4Iqw/t6sQWctatsTqFCGZ1BFRmBwJc4IDMUTUOX9LWqI+XiG2OlA/p3PscR2lwKUM7d MQyw== X-Forwarded-Encrypted: i=1; AJvYcCX4tipqnd2kpUguqtQ0tukOcZs4y+HCKH+gcrmH5dxVVUQCdIPekZR4KFo5XTVzfqamu2QuJ8h9RIzEV3XUZ3FDA3i1CTxL+/H+BiWSg/HVdjbIG1/vrxvTskULyDEULjnH9FTW X-Gm-Message-State: AOJu0YyuNZhlbbKMXskwhSnzFNyl0HMvI8iwV4ZPkZSo2mUPXGKJt6PL ty7hNou0FQIt/lCDkGkj3fHcshziwQ1zXgIynqwrREAR4l0ar7Jx X-Google-Smtp-Source: AGHT+IHgawRJtasMMLApQc5OHFyDRvuX4yFM6a3R+XcG8MbgkY8XrJ4Xajdc8fdCyowexgppBftf2w== X-Received: by 2002:adf:ebd2:0:b0:34f:824:17b2 with SMTP id v18-20020adfebd2000000b0034f082417b2mr3978192wrn.65.1715085856605; Tue, 07 May 2024 05:44:16 -0700 (PDT) Received: from localhost ([45.130.85.2]) by smtp.gmail.com with ESMTPSA id n8-20020adffe08000000b0034df2d0bd71sm12864608wrr.12.2024.05.07.05.44.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 May 2024 05:44:16 -0700 (PDT) From: Leone Fernando To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, willemb@google.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Leone Fernando Subject: [PATCH net-next v2 2/4] net: dst_cache: add input_dst_cache API Date: Tue, 7 May 2024 14:42:27 +0200 Message-Id: <20240507124229.446802-3-leone4fernando@gmail.com> In-Reply-To: <20240507124229.446802-1-leone4fernando@gmail.com> References: <20240507124229.446802-1-leone4fernando@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org The input_dst_cache allows fast lookup of frequently encountered dsts. In order to provide stable results, I implemented a simple linear hashtable with each bucket containing a constant amount of entries (DST_CACHE_INPUT_BUCKET_SIZE). Similarly to how the route hint is used, I defined the hashtable key to contain the daddr and the tos of the IP header. Lookup is performed in a straightforward manner: start at the bucket head corresponding the hashed key and search the following DST_CACHE_INPUT_BUCKET_SIZE entries of the array for a matching key. When inserting a new dst to the cache, if all the bucket entries are full, the oldest one is deleted to make room for the new dst. Signed-off-by: Leone Fernando --- include/net/dst_cache.h | 68 +++++++++++++++++++++ net/core/dst_cache.c | 132 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 200 insertions(+) diff --git a/include/net/dst_cache.h b/include/net/dst_cache.h index df6622a5fe98..b6f012ffeb86 100644 --- a/include/net/dst_cache.h +++ b/include/net/dst_cache.h @@ -7,12 +7,40 @@ #if IS_ENABLED(CONFIG_IPV6) #include #endif +#include + +#define DST_CACHE_INPUT_SHIFT (9) +#define DST_CACHE_INPUT_SIZE (1 << DST_CACHE_INPUT_SHIFT) +#define DST_CACHE_INPUT_BUCKET_SIZE (4) +#define DST_CACHE_INPUT_HASH_MASK (~(DST_CACHE_INPUT_BUCKET_SIZE - 1)) +#define INVALID_DST_CACHE_INPUT_KEY (~(u64)(0)) struct dst_cache { struct dst_cache_pcpu __percpu *cache; unsigned long reset_ts; }; +extern unsigned int dst_cache_net_id __read_mostly; + +/** + * idst_for_each_in_bucket - iterate over a dst cache bucket + * @pos: the type * to use as a loop cursor + * @head: the head of the cpu dst cache. + * @hash: the hash of the bucket + */ +#define idst_for_each_in_bucket(pos, head, hash) \ + for (pos = &head[hash]; \ + pos < &head[hash + DST_CACHE_INPUT_BUCKET_SIZE]; \ + pos++) + +/** + * idst_for_each_in_cache - iterate over the dst cache + * @pos: the type * to use as a loop cursor + * @head: the head of the cpu dst cache. + */ +#define idst_for_each_in_cache(pos, head) \ + for (pos = head; pos < head + DST_CACHE_INPUT_SIZE; pos++) + /** * dst_cache_get - perform cache lookup * @dst_cache: the cache @@ -106,4 +134,44 @@ int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp); */ void dst_cache_destroy(struct dst_cache *dst_cache); +/** + * dst_cache_input_get_noref - perform lookup in the input cache, + * return a noref dst + * @dst_cache: the input cache + * @skb: the packet according to which the dst entry will be searched + * local BH must be disabled. + */ +struct dst_entry *dst_cache_input_get_noref(struct dst_cache *dst_cache, + struct sk_buff *skb); + +/** + * dst_cache_input_add - add the dst of the given skb to the input cache. + * + * in case the cache bucket is full, the oldest entry will be deleted + * and replaced with the new one. + * @dst_cache: the input cache + * @skb: The packet according to which the dst entry will be searched + * + * local BH must be disabled. + */ +void dst_cache_input_add(struct dst_cache *dst_cache, + const struct sk_buff *skb); + +/** + * dst_cache_input_init - initialize the input cache, + * allocating the required storage + */ +int __init dst_cache_input_init(void); + +static inline u64 create_dst_cache_key_ip4(const struct sk_buff *skb) +{ + struct iphdr *iphdr = ip_hdr(skb); + + return (((u64)ntohl(iphdr->daddr)) << 8) | iphdr->tos; +} + +static inline u32 hash_dst_cache_key(u64 key) +{ + return hash_64(key, DST_CACHE_INPUT_SHIFT) & DST_CACHE_INPUT_HASH_MASK; +} #endif diff --git a/net/core/dst_cache.c b/net/core/dst_cache.c index 0c0bdb058c5b..843da4679488 100644 --- a/net/core/dst_cache.c +++ b/net/core/dst_cache.c @@ -13,6 +13,7 @@ #include #endif #include +#include struct dst_cache_pcpu { unsigned long refresh_ts; @@ -21,9 +22,12 @@ struct dst_cache_pcpu { union { struct in_addr in_saddr; struct in6_addr in6_saddr; + u64 key; }; }; +unsigned int dst_cache_net_id __read_mostly; + static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache, struct dst_entry *dst, u32 cookie) { @@ -181,3 +185,131 @@ void dst_cache_reset_now(struct dst_cache *dst_cache) } } EXPORT_SYMBOL_GPL(dst_cache_reset_now); + +static void dst_cache_input_set(struct dst_cache_pcpu *idst, + struct dst_entry *dst, u64 key) +{ + dst_cache_per_cpu_dst_set(idst, dst, 0); + idst->key = key; + idst->refresh_ts = jiffies; +} + +static struct dst_entry *__dst_cache_input_get_noref(struct dst_cache_pcpu *idst) +{ + struct dst_entry *dst = idst->dst; + + if (unlikely(dst->obsolete && !dst->ops->check(dst, idst->cookie))) { + dst_cache_input_set(idst, NULL, INVALID_DST_CACHE_INPUT_KEY); + goto fail; + } + + idst->refresh_ts = jiffies; + return dst; + +fail: + return NULL; +} + +struct dst_entry *dst_cache_input_get_noref(struct dst_cache *dst_cache, + struct sk_buff *skb) +{ + struct dst_entry *out_dst = NULL; + struct dst_cache_pcpu *pcpu_cache; + struct dst_cache_pcpu *idst; + u32 hash; + u64 key; + + pcpu_cache = this_cpu_ptr(dst_cache->cache); + key = create_dst_cache_key_ip4(skb); + hash = hash_dst_cache_key(key); + idst_for_each_in_bucket(idst, pcpu_cache, hash) { + if (key == idst->key) { + out_dst = __dst_cache_input_get_noref(idst); + goto out; + } + } +out: + return out_dst; +} + +static void dst_cache_input_reset_now(struct dst_cache *dst_cache) +{ + struct dst_cache_pcpu *caches; + struct dst_cache_pcpu *idst; + struct dst_entry *dst; + int i; + + for_each_possible_cpu(i) { + caches = per_cpu_ptr(dst_cache->cache, i); + idst_for_each_in_cache(idst, caches) { + idst->key = INVALID_DST_CACHE_INPUT_KEY; + dst = idst->dst; + if (dst) + dst_release(dst); + } + } +} + +static int __net_init dst_cache_input_net_init(struct net *net) +{ + struct dst_cache *dst_cache = net_generic(net, dst_cache_net_id); + + dst_cache->cache = (struct dst_cache_pcpu __percpu *)alloc_percpu_gfp(struct dst_cache_pcpu[DST_CACHE_INPUT_SIZE], + GFP_KERNEL | __GFP_ZERO); + if (!dst_cache->cache) + return -ENOMEM; + + dst_cache_input_reset_now(dst_cache); + return 0; +} + +static void __net_exit dst_cache_input_net_exit(struct net *net) +{ + struct dst_cache *dst_cache = net_generic(net, dst_cache_net_id); + + dst_cache_input_reset_now(dst_cache); + free_percpu(dst_cache->cache); + dst_cache->cache = NULL; +} + +static bool idst_empty(struct dst_cache_pcpu *idst) +{ + return idst->key == INVALID_DST_CACHE_INPUT_KEY; +} + +void dst_cache_input_add(struct dst_cache *dst_cache, const struct sk_buff *skb) +{ + struct dst_cache_pcpu *entry = NULL; + struct dst_cache_pcpu *pcpu_cache; + struct dst_cache_pcpu *idst; + u32 hash; + u64 key; + + pcpu_cache = this_cpu_ptr(dst_cache->cache); + key = create_dst_cache_key_ip4(skb); + hash = hash_dst_cache_key(key); + idst_for_each_in_bucket(idst, pcpu_cache, hash) { + if (idst_empty(idst)) { + entry = idst; + goto add_to_cache; + } + if (!entry || time_before(idst->refresh_ts, entry->refresh_ts)) + entry = idst; + } + +add_to_cache: + dst_cache_input_set(entry, skb_dst(skb), key); +} + +static struct pernet_operations dst_cache_input_ops __net_initdata = { + .init = dst_cache_input_net_init, + .exit = dst_cache_input_net_exit, + .id = &dst_cache_net_id, + .size = sizeof(struct dst_cache), +}; + +int __init dst_cache_input_init(void) +{ + return register_pernet_subsys(&dst_cache_input_ops); +} +subsys_initcall(dst_cache_input_init);