From patchwork Mon Feb 5 21:04:46 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Damato X-Patchwork-Id: 13546233 Received: from mail-pf1-f176.google.com (mail-pf1-f176.google.com [209.85.210.176]) (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 7D8D213B7AA for ; Mon, 5 Feb 2024 21:05:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707167105; cv=none; b=fEFdeyzY+35z7PIN5tHsElgJZpcEMMPlJdR7iYc/jSuEIYcTiV2eS4lECj6ZOO68EvCiwI5ruZGiztDO6f0ePHkQ5j2yup5S3QrC5jrszogEmvaqfK/90dyrFoqviVqjv/srbsP9sFop3sGLeOVm8x4u13/ZgJ4qDj8T1qLO9JY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707167105; c=relaxed/simple; bh=gQDKvGU/ghxRMfcflvdwZ024OwvFboTrSVuhgGT5PSY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Pga4PgqKfbfcjuFNGAs0dIDFGqTiV0WyW0WKQ+Iei8No2rz6gsXsW8uIjeyr97/WdL7V47sG6jhVWnee2KHN3lM3+tcLkJwgV50RVRZOP34lJt8hTyAHcQMPWNAEwnluI3lWFkqIKWPmGxWDqte/r1sR4kQgUo+VGBlQ+ZwE+9A= 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=Z9p1Typm; arc=none smtp.client-ip=209.85.210.176 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="Z9p1Typm" Received: by mail-pf1-f176.google.com with SMTP id d2e1a72fcca58-6e055baec89so162551b3a.1 for ; Mon, 05 Feb 2024 13:05:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastly.com; s=google; t=1707167102; x=1707771902; 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=//WWP3LIv7F69f9OvZE6kAJ/ncD/SOZi/tM1IcQuzWk=; b=Z9p1TypmZBncIk3hMD3ssbrfbGNvV//XFL3azhO5lzVQ3E3tzoSmMHONBmlisJZYiG ZMZiiGkgGSxZJjSft0H4/VdeUKNTyPmplMCthd9vrMGOs2hNYy8x5/AiCHv0h+h3s5jp 7v9zjyEi+3j6DrJxYtAlokCirPCDmcZDz/T2o= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707167102; x=1707771902; 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=//WWP3LIv7F69f9OvZE6kAJ/ncD/SOZi/tM1IcQuzWk=; b=D87uFnVRDgy+LvJLNaBOZw69a81gTM+Dqabgv6sG83txTzBKYyQ6qS7ssVlLq14wc7 wmFdGKkHhpVArOdVzFkVCLXPyywEWXBsCmqJuO6sMwECdBDxCIytiHOJch4BG56xhr40 mzP/JQCfROhgfqDV/StmV7gVU6Ek2+l1qNTT5IN4M4UWJ8kI3FwXu5MiILNePtfWS5ey QXB8d1rK7ksXW0BT3j8xNLPltUMJGanaCHe1+9YaUsCah8yjihrh0gPetOIOgZOcRHdc B7qemCM57NeUy5xbrKUBKa0m2MYutUUToEG/JJ7YZll3JGJsEWoja4XKdRYVwVSNAig7 fBJA== X-Gm-Message-State: AOJu0YzaoTQNe30U+32REjKBQ5yJRCLBhdKHB5xkvz5vhuL9Izw4+2hN ocFGKFosdeOERPWkoxIzlzZD6tu0WIL2nG/GNZxmwpnfcag1v+oTUfzhiaJNyqw= X-Google-Smtp-Source: AGHT+IGGPpScTLwYDVzDc0zc1eW3gIaxrebnnJTEJmL/cDQmZjF0qqfvEPqYHDHZJqzJ82rmQNqbbQ== X-Received: by 2002:aa7:88d0:0:b0:6e0:405f:ef8d with SMTP id k16-20020aa788d0000000b006e0405fef8dmr5450050pff.8.1707167101863; Mon, 05 Feb 2024 13:05:01 -0800 (PST) X-Forwarded-Encrypted: i=0; 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 Received: from localhost.localdomain ([2620:11a:c018:0:ea8:be91:8d1:f59b]) by smtp.gmail.com with ESMTPSA id p9-20020aa79e89000000b006e03efbcb3esm315750pfq.73.2024.02.05.13.04.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Feb 2024 13:05:01 -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 v6 1/4] eventpoll: support busy poll per epoll instance Date: Mon, 5 Feb 2024 21:04:46 +0000 Message-Id: <20240205210453.11301-2-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240205210453.11301-1-jdamato@fastly.com> References: <20240205210453.11301-1-jdamato@fastly.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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. Signed-off-by: Joe Damato --- fs/eventpoll.c | 49 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 4 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 3534d36a1474..ce75189d46df 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 */ + u64 busy_poll_usecs; #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -386,12 +388,44 @@ static inline int ep_events_available(struct eventpoll *ep) READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR; } +/** + * 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 inline bool busy_loop_ep_timeout(unsigned long start_time, struct eventpoll *ep) +{ +#ifdef CONFIG_NET_RX_BUSY_POLL + 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); + } +#endif + return true; +} + #ifdef CONFIG_NET_RX_BUSY_POLL +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 +438,7 @@ 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)) @@ -430,7 +464,8 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) struct socket *sock; struct sock *sk; - if (!net_busy_loop_on()) + ep = epi->ep; + if (!ep_busy_loop_on(ep)) return; sock = sock_from_file(epi->ffd.file); @@ -442,7 +477,6 @@ 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 @@ -466,6 +500,10 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { } +static inline bool ep_busy_loop_on(struct eventpoll *ep) +{ + return false; +} #endif /* CONFIG_NET_RX_BUSY_POLL */ /* @@ -2058,6 +2096,9 @@ 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;