From owner-freebsd-hackers@FreeBSD.ORG Wed Dec 15 05:15:45 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0BF6616A4CE for ; Wed, 15 Dec 2004 05:15:44 +0000 (GMT) Received: from mx1.netapp.com (mx1.netapp.com [216.240.18.38]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9315043D45 for ; Wed, 15 Dec 2004 05:15:42 +0000 (GMT) (envelope-from Kip.Macy@netapp.com) Received: from smtp2.corp.netapp.com (10.57.159.114) by mx1.netapp.com with ESMTP; 14 Dec 2004 21:15:43 -0800 X-Ironport-AV: i="3.87,143,1099296000"; d="scan'208"; a="49922307:sNHT18393700" Received: from svlexc01.hq.netapp.com (svlexc01.corp.netapp.com [10.57.156.135])iBF5FRId015687; Tue, 14 Dec 2004 21:15:41 -0800 (PST) Received: from burgundy.hq.netapp.com ([10.56.10.66]) by svlexc01.hq.netapp.com with Microsoft SMTPSVC(5.0.2195.6713); Tue, 14 Dec 2004 21:15:35 -0800 X-MimeOLE: Produced By Microsoft Exchange V6.0.6603.0 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Date: Tue, 14 Dec 2004 21:15:34 -0800 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: My project wish-list for the next 12 months Thread-Index: AcTiRquTlRk2X4HeRZyIxUxt0MwGhwAHjCsA From: "Macy, Kip" To: "Scott M. Ferris" X-OriginalArrivalTime: 15 Dec 2004 05:15:35.0022 (UTC) FILETIME=[1B43D0E0:01C4E265] X-Mailman-Approved-At: Wed, 15 Dec 2004 13:11:50 +0000 cc: hackers@freebsd.org cc: Peter Blok Subject: RE: My project wish-list for the next 12 months X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Dec 2004 05:15:45 -0000 Mbuf clusters can easily be allocated from their own pool, but I guess you're probably right about various bits of incidental memory allocation. -Kip -----Original Message----- From: Scott M. Ferris [mailto:sferris@gmail.com]=20 Sent: Tuesday, December 14, 2004 5:38 PM To: Macy, Kip Cc: Danny Braniss; hackers@freebsd.org; Peter Blok Subject: Re: My project wish-list for the next 12 months On Tue, 14 Dec 2004 17:05:25 -0800 (PST), Kip Macy wrote: > > Hardware-based iSCSI HBAs solve this by having their own memory and=20 > > TCP stack separate from the OS. Software-only iSCSI initiators such > > as linux-iscsi usually just hope it doesn't happen, and that's why I > > don't usually recommend software-only iSCSI initiators to anyone. >=20 > How is that any better than having the SW iscsi initiator pre-allocate > a pool of memory for its use at startup? You could preallocate, but the hard part would be getting the OS network stack to allocate from the iSCSI driver's preallocated memory pool, instead of calling the usual kernel memory allocator (or more likely as a fallback if the normal kernel allocation fails). How do you tell the TCP stack and NIC drivers to allocate control blocks, mbufs, and anything else they might need from the preallocated iSCSI pool? It's not a problem in theory, but in practice that's not something you usually see in the API for the network stack. --=20 Scott M. Ferris