From owner-svn-src-head@FreeBSD.ORG Fri Sep 3 07:05:34 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7D9C81065836; Fri, 3 Sep 2010 07:05:34 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-bw0-f54.google.com (mail-bw0-f54.google.com [209.85.214.54]) by mx1.freebsd.org (Postfix) with ESMTP id A29CE8FC18; Fri, 3 Sep 2010 07:05:33 +0000 (UTC) Received: by bwz20 with SMTP id 20so1547350bwz.13 for ; Fri, 03 Sep 2010 00:05:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:message-id:date:from :user-agent:mime-version:to:cc:subject:references:in-reply-to :x-enigmail-version:content-type:content-transfer-encoding; bh=usnGfA6Qc7YjL4/RznewnJ0jEPo0t1LH2oHvyf17bI0=; b=QvJcE+y6P3hu64C6CQwi67u8sW5y6CM9lyhjuSfK7+oDXMbxj5uTuicK4UHk1L4eTO uZ83IDwoPNkN83NwzTPykZNTw+DKQ9MCHUUJvPObwq6DCc5O6BcsFzicw7YrTAdzcun0 mlyVtte4WOk7q2hirlaSYNW5vtxAD0lVKZ0Kg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=q9TKZJqlMScN/ZSD397rXz+pNkeQJhdZ2jy7/GvQAuwASwJlsTuvO6wu+RKodkk4qx oO5o+0+BxQPdIaNRZ3najJZrX5jwd5pHjSxu76Q9INvJilgptzOkFMuUCMxU2RdI5pzf BitDARbk+p+SwPm2l9TUdaoMYBdzogHiegAKg= Received: by 10.204.133.91 with SMTP id e27mr147281bkt.197.1283496176043; Thu, 02 Sep 2010 23:42:56 -0700 (PDT) Received: from mavbook.mavhome.dp.ua (pc.mavhome.dp.ua [212.86.226.226]) by mx.google.com with ESMTPS id f18sm1169096bkf.15.2010.09.02.23.42.53 (version=SSLv3 cipher=RC4-MD5); Thu, 02 Sep 2010 23:42:54 -0700 (PDT) Sender: Alexander Motin Message-ID: <4C8098DF.4090606@FreeBSD.org> Date: Fri, 03 Sep 2010 09:42:39 +0300 From: Alexander Motin User-Agent: Thunderbird 2.0.0.24 (X11/20100402) MIME-Version: 1.0 To: Pawel Jakub Dawidek References: <201009021940.o82JeS8M017537@svn.freebsd.org> <20100902213926.GA2542@garage.freebsd.pl> <4C802028.4040400@FreeBSD.org> <20100903062355.GB1780@garage.freebsd.pl> In-Reply-To: <20100903062355.GB1780@garage.freebsd.pl> X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, "Justin T. Gibbs" , src-committers@FreeBSD.org Subject: Re: svn commit: r212160 - in head/sys: cam/ata cam/scsi cddl/contrib/opensolaris/uts/common/fs/zfs geom geom/sched kern sys X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 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: Fri, 03 Sep 2010 07:05:34 -0000 Pawel Jakub Dawidek wrote: > On Thu, Sep 02, 2010 at 04:07:36PM -0600, Justin T. Gibbs wrote: >> On 9/2/2010 3:39 PM, Pawel Jakub Dawidek wrote: >>> Don't you think it would be better to set the flag from within >>> g_io_request()? This way every BIO_FLUSH consumer doesn't have to >>> remember to set it. Or am I missing something? >> I don't feel strongly one way or the other, but I thought that >> g_io_request()'s job was to execute the request and to test invariants, >> not to set policy. Perhaps I misinterpreted it's role. > > Does BIO_FLUSH make sense without BIO_ORDERED? My understanding is that > it doesn't. IMHO it does. If caller manages ordering by waiting for all required writes to complete before submitting BIO_FLUSH. Such technics probably can be more difficult, but IMHO should give more flexibility to disk schedulers under parallel load. > But we still want BIO_ORDERED for use with BIO_WRITE for > write barriers without cache flushing. Sure. -- Alexander Motin