From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2602457-1520927192-2-13892285682052469438 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='de', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1520927191; b=BkSArnsUgUHD8/vBvwB3wCkhcFOXZRzRzh0FGer0ZAOCUCu HntNflB1eJO5l7/ba2h8h3m7KBNfAGxE3WoHdyJKomQG0PGs+C3X36C3Bn7jHPf5 KU4dvd7Jt3b7pttCAH8mKNdqnqeO4JEYg7DDUXkHe0ZzKyf6NANdwfqfaYZyLYBQ CTuZDypKlACIwKWfWlaD4v77JtJcqgy9EdVADlA7ekQrCFoFdvxfq/rc9aEvkTNT Xz2fEMNHeFI+vQVrxjGebZGYdyzw24C71ie+xy4R1nydYYmn936w6HUoSFy/2JqF Xdd1u1W5G0dvhR3y7fFMoc7z1cmEyVtkRI7LQFg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=arctest; t=1520927191; bh=9sI3MDZ8AbwPa425SWLt0BGDpv NFHuBc0peWpkT9MiA=; b=Ve29SyX+bhWhAErFDRpQbzLt8ZMGMaeGRIu7fzdi5u d7cStk1e2in8L5jtTdGbgKLJGMF7XymQyyT32IZWXymWcGyPgJSmbAuV45EjCB1W HyFPy8qiexOoACtf8d9XdTsy1pXVIs3m5pFkyPCtF0BY0dj4XikLKhOWjycF1itb WH1G6S3y7sV5Udv3I132gprIDBLHi5e/sXlCzx7fXe8gS2Dp5OCQAy8zA53v7O99 oWcSEtcs8zvdkBaZ2a8Q3ReqRalq9zMUJSk/3ChZWBn8Q7VjGhMshYgBI3dm3pHY o58CRaD8aXSZTEwi5oFlH43GEd8V10zCboRO750z1I1w== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=lst.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=0 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lst.de header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=lst.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=0 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lst.de header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751723AbeCMHq2 (ORCPT ); Tue, 13 Mar 2018 03:46:28 -0400 Received: from verein.lst.de ([213.95.11.211]:56481 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751615AbeCMHq2 (ORCPT ); Tue, 13 Mar 2018 03:46:28 -0400 Date: Tue, 13 Mar 2018 08:46:26 +0100 From: Christoph Hellwig To: viro@zeniv.linux.org.uk Cc: Avi Kivity , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: aio poll, io_pgetevents and a new in-kernel poll API V5 Message-ID: <20180313074626.GA32614@lst.de> References: <20180305212743.16664-1-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180305212743.16664-1-hch@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: ping? On Mon, Mar 05, 2018 at 01:27:07PM -0800, Christoph Hellwig wrote: > Hi all, > > this series adds support for the IOCB_CMD_POLL operation to poll for the > readyness of file descriptors using the aio subsystem. The API is based > on patches that existed in RHAS2.1 and RHEL3, which means it already is > supported by libaio. To implement the poll support efficiently new > methods to poll are introduced in struct file_operations: get_poll_head > and poll_mask. The first one returns a wait_queue_head to wait on > (lifetime is bound by the file), and the second does a non-blocking > check for the POLL* events. This allows aio poll to work without > any additional context switches, unlike epoll. > > To make the interface fully useful a new io_pgetevents system call is > added, which atomically saves and restores the signal mask over the > io_pgetevents system call. It it the logical equivalent to pselect and > ppoll for io_pgetevents. > > The corresponding libaio changes for io_pgetevents support and > documentation, as well as a test case will be posted in a separate > series. > > The changes were sponsored by Scylladb, and improve performance > of the seastar framework up to 10%, while also removing the need > for a privileged SCHED_FIFO epoll listener thread. > > git://git.infradead.org/users/hch/vfs.git aio-poll.5 > > Gitweb: > > http://git.infradead.org/users/hch/vfs.git/shortlog/refs/heads/aio-poll.5 > > Libaio changes: > > https://pagure.io/libaio.git io-poll > > Seastar changes (not updated for the new io_pgetevens ABI yet): > > https://github.com/avikivity/seastar/commits/aio > > Changes since V4: > - rebased ontop of Linux 4.16-rc4 > > Changes since V3: > - remove the pre-sleep ->poll_mask call in vfs_poll, > allow ->get_poll_head to return POLL* values. > > Changes since V2: > - removed a double initialization > - new vfs_get_poll_head helper > - document that ->get_poll_head can return NULL > - call ->poll_mask before sleeping > - various ACKs > - add conversion of random to ->poll_mask > - add conversion of af_alg to ->poll_mask > - lacking ->poll_mask support now returns -EINVAL for IOCB_CMD_POLL > - reshuffled the series so that prep patches and everything not > requiring the new in-kernel poll API is in the beginning > > Changes since V1: > - handle the NULL ->poll case in vfs_poll > - dropped the file argument to the ->poll_mask socket operation > - replace the ->pre_poll socket operation with ->get_poll_head as > in the file operations ---end quoted text---