From owner-svn-src-head@freebsd.org Sun Dec 10 02:37:01 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 187FCEA1B89 for ; Sun, 10 Dec 2017 02:37:01 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-io0-x233.google.com (mail-io0-x233.google.com [IPv6:2607:f8b0:4001:c06::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id D05C47FD20 for ; Sun, 10 Dec 2017 02:37:00 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-io0-x233.google.com with SMTP id v186so6223318iod.7 for ; Sat, 09 Dec 2017 18:37:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:cc; bh=iXYabrUA08ZVzNBib1BRuNxu9p33Ipi2r97rutu03Dk=; b=ADMXP3WMdo2cEkbMy1cDQE5M1EpjEO+eZGPp0p4AxM9jIt69BwE7BGWx9IU76Y14Nt ckRVeQYLMC//H8knXPnQcxBa2If/n1qPm5XnAvvsG5VDjmplrS8KHf9hxdpCRkPnD7f7 a4RI/KbjkY8Qy6vNEmh3l946Evzd9ZGZQXX6+xm5YZd0AXMhijb5JvI2LbPJ6dnRJBgd 0qE0VoVOA9LzBv+6iKOeCpeMElxt+dckGeyd7uu5H0Hm2LAWMC/DiJBCGIJWnTShWlzF tczZTQg5mC+GDYwOnbk9e4pvDRMUDvUjvG0YPnjytTW3U3nu5kOnlxOiFw3vyr9H1x3i 0daQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:cc; bh=iXYabrUA08ZVzNBib1BRuNxu9p33Ipi2r97rutu03Dk=; b=qQF/6XImx9xhkZw0rLObHwC5lpqoTwA4Vtm8lAgwKneCZT2GXzF06Di0Ze40KTeOEi /vFoq8Sy1obeCJwK56wSexBX97LrH5O2z5ZTXNL2cTx62I5PgK3mnlg/pu5whUZT4WXV NneC0SP2FEgFgdwVrBZCOA7sZRf2guLCrXL0sC6QNP1x9mUC4swKUoeDN04CywT7ZQ2V /pzCxi4ZmusI9Qv1wT6nJP3DEQo+xwWkGNjHPRZfsMu3Aaq1WfhtELbKizESQyPgX7bn d7SVqZlszBZfEXH6joyE6bkrEDw9CLsajuK0cLkjh/hw/g3VW/3nGp7x0J1gXdJJgrJM MS9Q== X-Gm-Message-State: AKGB3mJKiW0omrXexq08ePEz+34ZJkJdy2EwGNOAjnznel/DGyrl1K4c mT0wZAyY8H15lFHT/A4/dnbCI6Zi1xC4qnxBmmmmcQ== X-Received: by 10.107.52.140 with SMTP id b134mt23216767ioa.291.1512873419974; Sat, 09 Dec 2017 18:36:59 -0800 (PST) MIME-Version: 1.0 Sender: wlosh@bsdimp.com Received: by 10.79.108.204 with HTTP; Sat, 9 Dec 2017 18:36:59 -0800 (PST) X-Originating-IP: [2603:300b:6:5100:1052:acc7:f9de:2b6d] In-Reply-To: References: <201712091544.vB9FiVUI096790@repo.freebsd.org> From: Warner Losh Date: Sat, 9 Dec 2017 19:36:59 -0700 X-Google-Sender-Auth: JZyf-UZrCowTgk6H0I6IhUuyru4 Message-ID: Subject: Re: svn commit: r326731 - head/sys/ufs/ffs Cc: Mark Johnston , src-committers , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.25 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 10 Dec 2017 02:37:01 -0000 On Sat, Dec 9, 2017 at 11:03 AM, Andriy Gapon wrote: > On 09/12/2017 17:44, Mark Johnston wrote: > > Some GEOMs do not appear to handle BIO_ORDERED correctly, meaning that > the > > barrier write may not work as intended. There's a few places we send down a BIO_ORDERED BIO_FLUSH command (see softdep_synchronize for one). Will those matter? As I've noted elsewhere: I'd really like to kill BIO_ORDERED since it has too many icky effects (and BIO_FLUSH + BIO_ORDERED isn't guaranteed to do, well, anything since it can turn into a NOP in a number of places. Plus many of the implementations of BIO_ORDERED assume the drive is like SCSI and you just set the right tag to make it 'ordered'. For ATA we issue a non NCQ command, which is a full drain of outstanding commands, send this command, then start them again which really shuts down the parallelism we implemented NCQ for :(. We do similar for NVME which is even worse. There we have multiple submission queues in the hardware. To simulated it, we do a similar drain, but that's going to get in the way as we move to NUMA and systems where we try to do the I/O entirely on one CPU (both submission and completion) and ordered I/O is guaranteed lock contention. Warner