From patchwork Fri Feb 9 21:15:21 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Damato X-Patchwork-Id: 13551873 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) (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 662E339867 for ; Fri, 9 Feb 2024 21:15:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.180 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707513349; cv=none; b=Z4TPIaxozR61km8xhHUTa/HAS1Uqqr783TOXRtNwn+LKYSrA/vRTs9o3qC2g7lXT5jSumkQRZXOWAg2+3USXxoMfuslOa49TawXgnJlStxGjc3k9brqoNFgpTSJ86alPj2hsj2DCxzosJRqP+cwp3q72PwR3hwUstKoTa/qMTn0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707513349; c=relaxed/simple; bh=HZCLTuMgp/ckUlZ/e4J3shoTAMuEzpAwMA7BLa/9RiE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=mNiPtbQQc/OZKtqMe01P1wL+o8RxMw6/gQa+ugWQwAFTHFCHRNCAkWeoqPKy8i50yvfqwnfpi44feTnLBLJWdJIj/mJ9oSjJULsIdrlGxUr63ZXrJWdFHPNZzrn1Wnrs5ZNn0HnRFu/lN13W/KeNQTCv4RJ4zf4IEKoHwOMI9uU= 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=tYT0zxyG; arc=none smtp.client-ip=209.85.210.180 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="tYT0zxyG" Received: by mail-pf1-f180.google.com with SMTP id d2e1a72fcca58-6e02597a0afso1046752b3a.1 for ; Fri, 09 Feb 2024 13:15:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastly.com; s=google; t=1707513346; x=1708118146; 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=CnWe3jITTYQxWO7n4MTzpSC6BAe+szTuzlwikAcSvaM=; b=tYT0zxyGQALoutYHNBNhO5y5dZYLx2lgv1nqXnhIWkc76+UlnmfM6Fw9th4ZlAfatK xjzvDb4YzqRsFZvnvGncRJIIRKiawlyOdOoAwQ36Q4/yDxaHK0fgoUTreOygNbeLrH8q LArkw7y/XuC5RNRUWgP6M94Yg6jVPxr/lsCx0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707513346; x=1708118146; 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=CnWe3jITTYQxWO7n4MTzpSC6BAe+szTuzlwikAcSvaM=; b=OwhAsBPj0PSCeDu+e1Nuxo0U3LEHnnZ+JAAHWgB33v5IEvAbqfBqfAt3ThHUvvWMJP R44sC21YbvU/A5KJXuXF1uqJ0L8g+Obo37gxTsrrWLHgNOgRiBAv3PuojY4meOslftOv 6HCbxIVC1ydWVNGtp8dQ/NoCmnlUmssrfG0zt4kkhY4eFyxwVZDWQwS0JFPL8Y3QkEGC CB5eyruZ4Tp5q37T6J3pZGDsdDI4NTtVYncY6Irh0cx8riEtPJWYGecRhzO+wNrs4cT5 6hegJn4FRbmQUxG64AhSz/Yk8QdUoSej0nxzkj1u4DdR+avnFVC5OkeJUH/glwaQcnR/ 0SBA== X-Forwarded-Encrypted: i=1; AJvYcCWOTWu8UCTc7/3u20OyzCNsWDTnxbEHUmhN3tgVIIuDT8Es32i7LGiN61fgmwIDJXYO4lOQs87NQ93LToryC70dnkZegrjJ X-Gm-Message-State: AOJu0YxzWidgROktWUfWfi0anyz27PZlnkyJWKUxuhKb5LRxx2xUrDuE Ao3PdYE8l4q4ruzWVyV8VVQ1L0w3D2b/i0zllhiZMly2Ugfa6MtufeVBYya0x0M= X-Google-Smtp-Source: AGHT+IHrROXaC1T16mcElSwIXy7NMQMX/oEKLGAhaBXmlPXFeLNe23PLKNuB+mrTVCPIHPRvrmdang== X-Received: by 2002:aa7:8d0a:0:b0:6de:1e25:48e8 with SMTP id j10-20020aa78d0a000000b006de1e2548e8mr469606pfe.14.1707513345615; Fri, 09 Feb 2024 13:15:45 -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 x23-20020aa79197000000b006e05c801748sm969629pfa.199.2024.02.09.13.15.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Feb 2024 13:15:45 -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 v7 1/4] eventpoll: support busy poll per epoll instance Date: Fri, 9 Feb 2024 21:15:21 +0000 Message-Id: <20240209211528.51234-2-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240209211528.51234-1-jdamato@fastly.com> References: <20240209211528.51234-1-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;