From owner-freebsd-hackers@FreeBSD.ORG Wed May 10 00:01:48 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org 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 A3C0E16A41B for ; Wed, 10 May 2006 00:01:48 +0000 (UTC) (envelope-from doconnor@gsoft.com.au) Received: from cain.gsoft.com.au (cain.gsoft.com.au [203.31.81.10]) by mx1.FreeBSD.org (Postfix) with ESMTP id A08CC43D62 for ; Wed, 10 May 2006 00:01:39 +0000 (GMT) (envelope-from doconnor@gsoft.com.au) Received: from inchoate.gsoft.com.au (ppp223-61.lns2.adl4.internode.on.net [203.122.223.61]) (authenticated bits=0) by cain.gsoft.com.au (8.13.5/8.13.4) with ESMTP id k4A0163a001466 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 10 May 2006 09:31:26 +0930 (CST) (envelope-from doconnor@gsoft.com.au) From: "Daniel O'Connor" To: freebsd-hackers@freebsd.org Date: Wed, 10 May 2006 09:30:27 +0930 User-Agent: KMail/1.9.1 References: <67beabb0605081559j3904ada3vb5a952cc3195ae44@mail.gmail.com> In-Reply-To: <67beabb0605081559j3904ada3vb5a952cc3195ae44@mail.gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1261166.GfGITZO878"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200605100930.28030.doconnor@gsoft.com.au> X-Spam-Score: 0 () X-Scanned-By: MIMEDefang 2.56 on 203.31.81.10 Cc: Bharma Ji Subject: Re: differences between M_CACHE, M_DEVBUF, M_TEMP X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 May 2006 00:01:50 -0000 --nextPart1261166.GfGITZO878 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Tuesday 09 May 2006 08:29, Bharma Ji wrote: > I am trying to understand the difference in these three different memorie= s. > Code comments in kern_malloc.c says that M_DEVBUF should be used for devi= ce > driver. I didn't however see any major difference between the three > memories. Can a device theoretically take up memory from M_TEMP (or > M_CACHE) segment? Similary can device drivers using M_DEVBUF also allocate > from M_CACHE / M_TEMP if needed. The M_* stuff is just a categorisation for memory allocations. Run vmstat -= m=20 to see what I mean. AFAIK the actual take has no bearing on the performance of the allocation=20 itself. =2D-=20 Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C --nextPart1261166.GfGITZO878 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (FreeBSD) iD8DBQBEYS0c5ZPcIHs/zowRAgqvAKCScKFU0oVNRhKz4vXyjYmwTMoq1ACggD+6 Ce75GuHX/jjxAsvdoB09OXI= =xlfU -----END PGP SIGNATURE----- --nextPart1261166.GfGITZO878--