From patchwork Tue Feb 13 06:16:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Damato X-Patchwork-Id: 13554464 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-pf1-f181.google.com (mail-pf1-f181.google.com [209.85.210.181]) (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 492E7134C9 for ; Tue, 13 Feb 2024 06:17:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707805022; cv=none; b=B109HVuAxC1Rp7TPR7rGSpQenEb/WOfaYuMHPlOMj7p1JX9pIRJ0f/WpT2yMQhzH0CleufgMNsoJmKfpl5EiS7rXLwoWCV5fC6cz4HIsxDvG1sdi0v8BZcDmCgGXWYIQbj99nJOGIe2YPRgjWzNrV2J03XeqAtCaffwLKiv17zg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707805022; c=relaxed/simple; bh=+BdDiZtulZrbvLpADjlE62DUPuOp3KejqJWNkuE2SMM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Fin1XgL+vNM4IL/LgFC/Ova5XBKIv8uqBYectv//OBF7dNbzpjvSign0UX22bmCSxQaskvXWD+VIgUV0epEVWrJHgooH3O0zFozHZOBINx22qWEgY2V32gkuJU9RaYRtZPJCt3NlivW306HBLt1uT/5eHk22n0xkd0c/m94faV8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com; spf=pass smtp.mailfrom=fastly.com; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b=V4tUlKDt; arc=none smtp.client-ip=209.85.210.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fastly.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b="V4tUlKDt" Received: by mail-pf1-f181.google.com with SMTP id d2e1a72fcca58-6e0a37751cbso1750445b3a.2 for ; Mon, 12 Feb 2024 22:17:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastly.com; s=google; t=1707805020; x=1708409820; 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=TWK7Tcl4v78WKhBmDih4hp4aKoxAkEp5jIDo2VrMgEA=; b=V4tUlKDtNG5nDcAVYnEBlnYWOg1iCN64lyuhme3cICIR1UcXjoVt/fCCOWn9ZkKsrM +OXcUk7ZlLq4QByOlywAFy5AvXdM/mr+I/R5IZg6BkhvtHOrt4fhVOPrI9+ehJQumqOk K3C173ell5/3VM6iH+r5fFz65o1kDHq4l3w8g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707805020; x=1708409820; 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=TWK7Tcl4v78WKhBmDih4hp4aKoxAkEp5jIDo2VrMgEA=; b=Fr5FqeTQ+i/07SZ8+0R75u/rgs/wlUSFjxRgM+hdfWfnB/X1JSkkxy76wFW5WfXY63 DG5JmMixuLC+uqywaodzwqxFx4hhjT06CePIRIZJSmwa/R0zb4wNhD5aBuhvE+pX8qrX xrBcfXcK+gt7j5cceukHgJv0TTCpcdmXHZn9AOgd3P5xMt26xknIvQ9NHWNWHv1y+InY 8lGvpEoxkiyP+8YuJa5V/jAlkNYBj5waRJXELMyzo3byijgqZsYPxsROwmP6G+o/I2AI T0xJEe5civ9UI996yIaNBBGpylT2Bh8iPgXl+I3UVF8+GfyVa2oOBBVga/lIkG9Crkgf SUzA== X-Forwarded-Encrypted: i=1; AJvYcCXW5PFl44d5mbHB4+2s9em9fwLHufAlkvrn5zn1p1PRiiyYi6H8Z+BoOu+tBHI8HW39VhbQ9DISq7EGl8RVGPApwYnAS+Oa X-Gm-Message-State: AOJu0YySifxJx2QQtf11rbnTmhwA4/Ka5GcdvCuG4srXkkk86ZZXW363 4m+S2I+PNY+yCyz65719J0hrCt1ZkMsjm0PepEzuXgrBzJZPLnICIfXw9y1alh4= X-Google-Smtp-Source: AGHT+IFA7EAAn3meKC9yNTCZGB0U0AKSVSGB9K2EIMouJRX02mBckAKZdErIH3xk401Zifh9l4gNXg== X-Received: by 2002:a05:6a00:bc6:b0:6e0:99d6:490 with SMTP id x6-20020a056a000bc600b006e099d60490mr7327725pfu.21.1707805020617; Mon, 12 Feb 2024 22:17:00 -0800 (PST) X-Forwarded-Encrypted: i=1; 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 Received: from localhost.localdomain ([2620:11a:c018:0:ea8:be91:8d1:f59b]) by smtp.gmail.com with ESMTPSA id n19-20020a638f13000000b005dc87f5dfcfsm342936pgd.78.2024.02.12.22.16.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Feb 2024 22:17:00 -0800 (PST) From: Joe Damato To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: chuck.lever@oracle.com, jlayton@kernel.org, linux-api@vger.kernel.org, brauner@kernel.org, edumazet@google.com, davem@davemloft.net, alexander.duyck@gmail.com, sridhar.samudrala@intel.com, kuba@kernel.org, willemdebruijn.kernel@gmail.com, weiwan@google.com, David.Laight@ACULAB.COM, arnd@arndb.de, sdf@google.com, amritha.nambiar@intel.com, Joe Damato , Alexander Viro , Jan Kara , linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)) Subject: [PATCH net-next v8 1/4] eventpoll: support busy poll per epoll instance Date: Tue, 13 Feb 2024 06:16:42 +0000 Message-Id: <20240213061652.6342-2-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240213061652.6342-1-jdamato@fastly.com> References: <20240213061652.6342-1-jdamato@fastly.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 Allow busy polling on a per-epoll context basis. The per-epoll context usec timeout value is preferred, but the pre-existing system wide sysctl value is still supported if it specified. busy_poll_usecs is a u32, but in a follow up patch the ioctl provided to the user only allows setting a value from 0 to S32_MAX. Signed-off-by: Joe Damato Acked-by: Stanislav Fomichev Reviewed-by: Eric Dumazet --- fs/eventpoll.c | 44 +++++++++++++++++++++++++++++++++++++++----- 1 file changed, 39 insertions(+), 5 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 3534d36a1474..401f865eced9 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -227,6 +227,8 @@ struct eventpoll { #ifdef CONFIG_NET_RX_BUSY_POLL /* used to track busy poll napi_id */ unsigned int napi_id; + /* busy poll timeout */ + u32 busy_poll_usecs; #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -387,11 +389,41 @@ static inline int ep_events_available(struct eventpoll *ep) } #ifdef CONFIG_NET_RX_BUSY_POLL +/** + * busy_loop_ep_timeout - check if busy poll has timed out. The timeout value + * from the epoll instance ep is preferred, but if it is not set fallback to + * the system-wide global via busy_loop_timeout. + * + * @start_time: The start time used to compute the remaining time until timeout. + * @ep: Pointer to the eventpoll context. + * + * Return: true if the timeout has expired, false otherwise. + */ +static bool busy_loop_ep_timeout(unsigned long start_time, + struct eventpoll *ep) +{ + unsigned long bp_usec = READ_ONCE(ep->busy_poll_usecs); + + if (bp_usec) { + unsigned long end_time = start_time + bp_usec; + unsigned long now = busy_loop_current_time(); + + return time_after(now, end_time); + } else { + return busy_loop_timeout(start_time); + } +} + +static bool ep_busy_loop_on(struct eventpoll *ep) +{ + return !!ep->busy_poll_usecs || net_busy_loop_on(); +} + static bool ep_busy_loop_end(void *p, unsigned long start_time) { struct eventpoll *ep = p; - return ep_events_available(ep) || busy_loop_timeout(start_time); + return ep_events_available(ep) || busy_loop_ep_timeout(start_time, ep); } /* @@ -404,7 +436,7 @@ static bool ep_busy_loop(struct eventpoll *ep, int nonblock) { unsigned int napi_id = READ_ONCE(ep->napi_id); - if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on()) { + if (napi_id >= MIN_NAPI_ID && ep_busy_loop_on(ep)) { napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep, false, BUSY_POLL_BUDGET); if (ep_events_available(ep)) @@ -425,12 +457,12 @@ static bool ep_busy_loop(struct eventpoll *ep, int nonblock) */ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { - struct eventpoll *ep; + struct eventpoll *ep = epi->ep; unsigned int napi_id; struct socket *sock; struct sock *sk; - if (!net_busy_loop_on()) + if (!ep_busy_loop_on(ep)) return; sock = sock_from_file(epi->ffd.file); @@ -442,7 +474,6 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) return; napi_id = READ_ONCE(sk->sk_napi_id); - ep = epi->ep; /* Non-NAPI IDs can be rejected * or @@ -2058,6 +2089,9 @@ static int do_epoll_create(int flags) error = PTR_ERR(file); goto out_free_fd; } +#ifdef CONFIG_NET_RX_BUSY_POLL + ep->busy_poll_usecs = 0; +#endif ep->file = file; fd_install(fd, file); return fd;