From owner-freebsd-arch@FreeBSD.ORG Fri Apr 15 02:26:48 2011 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 403ED106564A; Fri, 15 Apr 2011 02:26:48 +0000 (UTC) (envelope-from alan.l.cox@gmail.com) Received: from mail-fx0-f54.google.com (mail-fx0-f54.google.com [209.85.161.54]) by mx1.freebsd.org (Postfix) with ESMTP id 9F0B08FC08; Fri, 15 Apr 2011 02:26:47 +0000 (UTC) Received: by fxm11 with SMTP id 11so2145442fxm.13 for ; Thu, 14 Apr 2011 19:26:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:reply-to:in-reply-to:references :date:message-id:subject:from:to:cc:content-type; bh=CdbjE1fRHu0QKk7BZwTkgIFAcBTVysEDnidonJJlTys=; b=S9zihSSnfVjTZBFQXmnSemx6+t0IT2qqmbnsUJAL0O3srWRdpKu4AYifVH1sMiBOgr RpzpxUblYsYhPvUaMI9jrwr0zO1BZbD2qYhQs80k39FbjI+F873LvV9zmFX+/HqYsetv o+WOOd+SQEtBk0VPNrEbohkutvmkFpEhfFBbg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:reply-to:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; b=ECo6AX6qH0X5I+yxAt5DdqDMu/2c8a7raxpAjSoEKe+XVD3QTKFAhIWmM9hxySWd8T UeHz9NwCXidlZZnTEQMQOszsIWL0YpkzMS4VQI2tjGRX67E2bAAMIIMpo/UHrRSmNahN 30nrI5kljDLlyWvJHrzlQOhbz5U9Ev2z7flt8= MIME-Version: 1.0 Received: by 10.223.58.72 with SMTP id f8mr1489313fah.137.1302832724872; Thu, 14 Apr 2011 18:58:44 -0700 (PDT) Received: by 10.223.89.143 with HTTP; Thu, 14 Apr 2011 18:58:44 -0700 (PDT) In-Reply-To: References: Date: Thu, 14 Apr 2011 20:58:44 -0500 Message-ID: From: Alan Cox To: mdf@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: FreeBSD Arch Subject: Re: posix_fallocate(2) X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: alc@freebsd.org List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 15 Apr 2011 02:26:48 -0000 On Thu, Apr 14, 2011 at 2:35 PM, wrote: > For work we need a functionality in our filesystem that is pretty much > like posix_fallocate(2), so we're using the name and I've added a > default VOP_ALLOCATE definition that does the right, but dumb, thing. > > The most recent mention of this function in FreeBSD was another thread > lamenting it's failure to exist: > http://lists.freebsd.org/pipermail/freebsd-ports/2010-February/059268.html > > The attached files are the core of the kernel implementation of the > syscall and a default VOP for any filesystem not supporting > VOP_ALLOCATE, which allows the syscall to work as expected but in a > non-performant manner. I didn't see this syscall in NetBSD or > OpenBSD, so I plan to add it to the end of our syscall table. > > What I wanted to check with -arch about was: > > 1) is there still a desire for this syscall? > Page 10 of my paper at http://www.jeffshafer.com/publications/papers/shafer_ispass10.pdf describes how it could improve Hadoop performance (if properly implemented). So, I would encourage you to add it. Alan