From patchwork Tue Jul 2 14:24:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leone Fernando X-Patchwork-Id: 13719819 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-wm1-f65.google.com (mail-wm1-f65.google.com [209.85.128.65]) (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 842201BA09E; Tue, 2 Jul 2024 14:26:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.65 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719930377; cv=none; b=C/T7V2/DDtGlu6xS/BIi/Kt6fuafcuZWi2Md2PjFRQ4Mi8zUWNxdl2IAwqtQg4iOQ2RJFhMOeZsxzRCtp5TnEiUyqzguVolq2FqfBYrux0qFfIDVHYrBYDOil6ebq/2hnA/0Ai+HnrrXf/9Dj0Yk8i0MNe8Ub3MSc5dZGkoMW0I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719930377; c=relaxed/simple; bh=KHCrWkl9Se/TbfbJJGjjfw7jH7ZiLIy1EKVjnOWIHYI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=A7BHGyRuKdrDfWb9zZbbWCw+OHo4PEsqC28IkKo0RkTOaBqW2kQkrIdpC0JdMLwok4DkwDZNAXS0jhHu6Yt/z5arS6WRkQeoqGg/hV7c07PIlisZ5m4WXUas1j+64kObBWEHZIPpN7rFlsFZ7zPbBp6ZUZcZ4DSYM1VAcWY3fYQ= 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=NGPOrTsH; arc=none smtp.client-ip=209.85.128.65 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="NGPOrTsH" Received: by mail-wm1-f65.google.com with SMTP id 5b1f17b1804b1-425680b1d3aso29693455e9.2; Tue, 02 Jul 2024 07:26:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1719930374; x=1720535174; 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=fQPrrltauyj4cq2R5p8oo5i6avmreGA0Gnt1HK9Fs3o=; b=NGPOrTsHSHiGJtV8fybzP84w+ggoVubvyJH8C9uGw15Wbx4UnkMUgvQXLHW3M5NVqo DP3H9X4EnkMt//BYss4x58MmYqLReUPbnIRQ74zy7x8bd8gpiVEAFsmRAIXPVCKn3Odz V9exDQn+eldRaI+lOywU/Q94fzRe1bo9yelhCwkBvxsx0CYvJTIK8QZuRiTn9RikyxQL JA3QGZXHxFVWjDzS+rAXX9HgO0NdRqEKq64vLz1VBypehb57CY0r0ReQE6svSx562llk bkLNGjKLWv6CyHOCgWTZytrfsHQJR3xRHHJSqHbNZIMpJ2Lm19+E458eUhbV4vIy77Io N+4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719930374; x=1720535174; 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=fQPrrltauyj4cq2R5p8oo5i6avmreGA0Gnt1HK9Fs3o=; b=KSE02q6jUAbV5cuoySk7ek+ySRqOGm05lluISRglCdzI7Vtof/bBzi/EfRLXZMJ7U+ Bs7SKtEgDXYW/9znjBINy2mHi9aadzdhi+C0vxttqh9YMicLATlio3pqYiWVOmGBIuAC 5r8rg5JsjzsUBCq5CZ3+U7hMlQojD4LR68QP/WjzMmvRvAmChIe1U+Ivxs0x1BUS9GHJ si+H/BHTYWdGZJHzSCBx/QxfBqLalF4RsYKY3N1NpLFblUyWf0xlHxs9Yo+DsaHgDDsQ dj1tD2sWSjRHxU514TFVI5jdEvyUT5bI5VP5koERIaSjFtODt01dYb45cfLermT0KdrF BBPw== X-Forwarded-Encrypted: i=1; AJvYcCUlcqWlstfM7sXK2IdnZunepIPdJ8Trt+mpobB6mIB2FfMnT1YZ5jPAiSxvMG+e3o74QRuL3/TNi4FeyFwhMIWIFfxQm9Db0KIEoYJGX13jOfQb6Nzh9w2aX/YA2EHKKH+Tbg+r X-Gm-Message-State: AOJu0Ywm4a2hesEma7krc/e5/0f7hN4YTaYIKm/8V3tm0FuhCq1HZiKK SX92QCl7wm/kPcxwTw3/XyoRyiCiXjLtuZC1ob3Q8b1BxDCn/sxT X-Google-Smtp-Source: AGHT+IFSNK2gBuL1gmt/Jpoyd+WxHJjZK7yJyQGrccllLCNNbRljlwpZH9aeQSKFQVfkUomEdhEy8w== X-Received: by 2002:a05:600c:4792:b0:425:6207:12b4 with SMTP id 5b1f17b1804b1-4257a03c80emr70301695e9.24.1719930373805; Tue, 02 Jul 2024 07:26:13 -0700 (PDT) Received: from localhost ([45.130.85.5]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4256af5b66csm196719445e9.18.2024.07.02.07.26.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jul 2024 07:26:13 -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, 2 Jul 2024 16:24:04 +0200 Message-Id: <20240702142406.465415-3-leone4fernando@gmail.com> In-Reply-To: <20240702142406.465415-1-leone4fernando@gmail.com> References: <20240702142406.465415-1-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 b4a55d2d5e71..97500536c421 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 70c634b9e7b0..435fd5595fe2 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) { @@ -184,3 +188,131 @@ 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);