From patchwork Thu Jan 25 22:56:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Damato X-Patchwork-Id: 13531812 Received: from mail-oo1-f42.google.com (mail-oo1-f42.google.com [209.85.161.42]) (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 16DAD111B5 for ; Thu, 25 Jan 2024 22:57:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706223468; cv=none; b=WFbNltc4JfkqdZlXoXC6zwJ/MdrI9fEHFqZwHCs+CHV/YSkzdQUrxE4y08U3TXTazsiIay/4gYQL5HjC8bPAPKClarXyIASD9FIFzdAgmEMgTHrGUOa2TnPSAoc5hFO0drtIABaXuRhAtmn1EhstK5u2E5IuB3z/l293rtvG+lY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706223468; c=relaxed/simple; bh=qkngexUKlfn+hMPunN78J4XlCpnaY0JzFvOY2CvOwFw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=HGka6FUj+N+JGz3wk6n5wjddlND8LJ8mGw7SkqQtzWHyMk1x3Kk4Taz8Xtb5hg6mso0yR3Hry0BHVNCc7uZUXT7wHn/4bock/19fPgbRh2XVD5h1v+8dC2cxE7yvJe5hB9ng4vMSyTcxI+wsYlb+jbogC6CY8k+ZBLQ7wX5HrCc= 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=LNteaX/L; arc=none smtp.client-ip=209.85.161.42 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="LNteaX/L" Received: by mail-oo1-f42.google.com with SMTP id 006d021491bc7-5999ec531dcso1915043eaf.3 for ; Thu, 25 Jan 2024 14:57:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastly.com; s=google; t=1706223466; x=1706828266; 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=VV39OAkRpCVAHLKUI3lU3BvBDLbvOa7qJKwdNWq/qLo=; b=LNteaX/L+A7wlIGmFAxlvRJaShq9jtlCsS7lt6LO3BAt07Nb19rEMQjRcCbK+Uam8B AzOj6bZyX0A1KQiqGpZHWYCmB10uu9k3eS+FBEcf8d71RhKk3zsQkwoij+2OQbtvxmKg xwJNF9rgsMOWKsDTUZWkAu5aK+9qfLiWBUDco= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706223466; x=1706828266; 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=VV39OAkRpCVAHLKUI3lU3BvBDLbvOa7qJKwdNWq/qLo=; b=O/I4c90N7to2SqZ2TiT2r6qhwAhMUQoISRoNBSYEBvJ629QWnu7Nj2o2irh9ucfuYN ef6tMq2YtRUjvoo5LfF56I6Px2JJtuGRSPMSSYwS4LtWD2kI3JKK6uaKp1UTx4kp/6ew 3T4sSkuhV3Eg0Ir9UaKPHP/lUM7BKuqtfdW53mSGFGv/XnRo1CIFQX3FkFQPbksY5Ah/ V70RBPyk8GWdZTrA4Fl+F/TaK4js7DPI/OWWM1AwRlw2Tsl/JCwS+8QSoJUZNoUooRLN tkGoE1YcTmphRFhNm4n8sQuBy+TxwgSGg6MsJI0XAeFm25+rxd43mkgGhRDQ5nALrgVB swig== X-Gm-Message-State: AOJu0Yzt7VFCrl+CwAK4oENFImToBnTLuC3r3+V1DKzprVIevWAwTQ95 xXoPwzv54uLcbaTq1Ob46PjVIbfqtxeXVGd4wDU86oydMe/+qNJYsRqJx6ZVkxg= X-Google-Smtp-Source: AGHT+IEBJKdnv/0PWa1kjfk6mL3RWJeaJjGcRTqPE4k+O8aLjsFMGw7r0OXSIIiMsItoxHdR43gtew== X-Received: by 2002:a05:6359:4588:b0:176:6270:8cb6 with SMTP id no8-20020a056359458800b0017662708cb6mr549318rwb.25.1706223466122; Thu, 25 Jan 2024 14:57:46 -0800 (PST) Received: from localhost.localdomain ([2620:11a:c018:0:ea8:be91:8d1:f59b]) by smtp.gmail.com with ESMTPSA id z24-20020a631918000000b005d68962e1a7sm19948pgl.24.2024.01.25.14.57.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Jan 2024 14:57:45 -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, Joe Damato , Alexander Viro , Jan Kara , linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)) Subject: [PATCH net-next v3 1/3] eventpoll: support busy poll per epoll instance Date: Thu, 25 Jan 2024 22:56:57 +0000 Message-Id: <20240125225704.12781-2-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240125225704.12781-1-jdamato@fastly.com> References: <20240125225704.12781-1-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. Note that this change uses an xor: either per epoll instance busy polling is enabled on the epoll instance or system wide epoll is enabled. Enabling both is disallowed. 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..4503fec01278 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; From patchwork Thu Jan 25 22:56:58 2024 Content-Type: text/plain; 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Thu, 25 Jan 2024 14:57:47 -0800 (PST) Received: from localhost.localdomain ([2620:11a:c018:0:ea8:be91:8d1:f59b]) by smtp.gmail.com with ESMTPSA id z24-20020a631918000000b005d68962e1a7sm19948pgl.24.2024.01.25.14.57.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Jan 2024 14:57:47 -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, Joe Damato , Alexander Viro , Jan Kara , linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)) Subject: [PATCH net-next v3 2/3] eventpoll: Add per-epoll busy poll packet budget Date: Thu, 25 Jan 2024 22:56:58 +0000 Message-Id: <20240125225704.12781-3-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240125225704.12781-1-jdamato@fastly.com> References: <20240125225704.12781-1-jdamato@fastly.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 When using epoll-based busy poll, the packet budget is hardcoded to BUSY_POLL_BUDGET (8). Users may desire larger busy poll budgets, which can potentially increase throughput when busy polling under high network load. Other busy poll methods allow setting the busy poll budget via SO_BUSY_POLL_BUDGET, but epoll-based busy polling uses a hardcoded value. Fix this edge case by adding support for a per-epoll context busy poll packet budget. If not specified, the default value (BUSY_POLL_BUDGET) is used. Signed-off-by: Joe Damato --- fs/eventpoll.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 4503fec01278..40bd97477b91 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -229,6 +229,8 @@ struct eventpoll { unsigned int napi_id; /* busy poll timeout */ u64 busy_poll_usecs; + /* busy poll packet budget */ + u16 busy_poll_budget; #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -437,10 +439,14 @@ static bool ep_busy_loop_end(void *p, unsigned long start_time) static bool ep_busy_loop(struct eventpoll *ep, int nonblock) { unsigned int napi_id = READ_ONCE(ep->napi_id); + u16 budget = READ_ONCE(ep->busy_poll_budget); + + if (!budget) + budget = BUSY_POLL_BUDGET; if ((napi_id >= MIN_NAPI_ID) && ep_busy_loop_on(ep)) { napi_busy_loop(napi_id, nonblock ? 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Thu, 25 Jan 2024 14:57:53 -0800 (PST) Received: from localhost.localdomain ([2620:11a:c018:0:ea8:be91:8d1:f59b]) by smtp.gmail.com with ESMTPSA id z24-20020a631918000000b005d68962e1a7sm19948pgl.24.2024.01.25.14.57.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Jan 2024 14:57:53 -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, Joe Damato , Jonathan Corbet , Alexander Viro , Jan Kara , Michael Ellerman , Greg Kroah-Hartman , Nathan Lynch , Steve French , Thomas Zimmermann , Jiri Slaby , Julien Panis , Arnd Bergmann , Andrew Waterman , Thomas Huth , Palmer Dabbelt , linux-doc@vger.kernel.org (open list:DOCUMENTATION), linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)) Subject: [PATCH net-next v3 3/3] eventpoll: Add epoll ioctl for epoll_params Date: Thu, 25 Jan 2024 22:56:59 +0000 Message-Id: <20240125225704.12781-4-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240125225704.12781-1-jdamato@fastly.com> References: <20240125225704.12781-1-jdamato@fastly.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add an ioctl for getting and setting epoll_params. User programs can use this ioctl to get and set the busy poll usec time or packet budget params for a specific epoll context. Signed-off-by: Joe Damato --- .../userspace-api/ioctl/ioctl-number.rst | 1 + fs/eventpoll.c | 64 +++++++++++++++++++ include/uapi/linux/eventpoll.h | 12 ++++ 3 files changed, 77 insertions(+) diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 457e16f06e04..b33918232f78 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -309,6 +309,7 @@ Code Seq# Include File Comments 0x89 0B-DF linux/sockios.h 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range +0x8A 00-1F linux/eventpoll.h 0x8B all linux/wireless.h 0x8C 00-3F WiNRADiO driver diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 40bd97477b91..73ae886efb8a 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -6,6 +6,8 @@ * Davide Libenzi */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include #include #include @@ -37,6 +39,7 @@ #include #include #include +#include #include /* @@ -495,6 +498,39 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) ep->napi_id = napi_id; } +static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct eventpoll *ep; + struct epoll_params epoll_params; + void __user *uarg = (void __user *) arg; + + ep = file->private_data; + + switch (cmd) { + case EPIOCSPARAMS: + if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params))) + return -EFAULT; + + if (epoll_params.busy_poll_budget > NAPI_POLL_WEIGHT && + !capable(CAP_NET_ADMIN)) + return -EPERM; + + ep->busy_poll_usecs = epoll_params.busy_poll_usecs; + ep->busy_poll_budget = epoll_params.busy_poll_budget; + return 0; + case EPIOCGPARAMS: + memset(&epoll_params, 0, sizeof(epoll_params)); + epoll_params.busy_poll_usecs = ep->busy_poll_usecs; + epoll_params.busy_poll_budget = ep->busy_poll_budget; + if (copy_to_user(uarg, &epoll_params, sizeof(epoll_params))) + return -EFAULT; + return 0; + default: + return -ENOIOCTLCMD; + } +} + #else static inline bool ep_busy_loop(struct eventpoll *ep, int nonblock) @@ -510,6 +546,12 @@ static inline bool ep_busy_loop_on(struct eventpoll *ep) { return false; } + +static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + return -EOPNOTSUPP; +} #endif /* CONFIG_NET_RX_BUSY_POLL */ /* @@ -869,6 +911,26 @@ static void ep_clear_and_put(struct eventpoll *ep) ep_free(ep); } +static long ep_eventpoll_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + int ret; + + if (!is_file_epoll(file)) + return -EINVAL; + + switch (cmd) { + case EPIOCSPARAMS: + case EPIOCGPARAMS: + ret = ep_eventpoll_bp_ioctl(file, cmd, arg); + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + static int ep_eventpoll_release(struct inode *inode, struct file *file) { struct eventpoll *ep = file->private_data; @@ -975,6 +1037,8 @@ static const struct file_operations eventpoll_fops = { .release = ep_eventpoll_release, .poll = ep_eventpoll_poll, .llseek = noop_llseek, + .unlocked_ioctl = ep_eventpoll_ioctl, + .compat_ioctl = compat_ptr_ioctl, }; /* diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h index cfbcc4cc49ac..8eb0fdbce995 100644 --- a/include/uapi/linux/eventpoll.h +++ b/include/uapi/linux/eventpoll.h @@ -85,4 +85,16 @@ struct epoll_event { __u64 data; } EPOLL_PACKED; +struct epoll_params { + u64 busy_poll_usecs; + u16 busy_poll_budget; + + /* for future fields */ + u8 data[118]; +} EPOLL_PACKED; + +#define EPOLL_IOC_TYPE 0x8A +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params) +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params) + #endif /* _UAPI_LINUX_EVENTPOLL_H */