From owner-freebsd-net@FreeBSD.ORG Thu Feb 13 18:14:23 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id B7CF4284 for ; Thu, 13 Feb 2014 18:14:23 +0000 (UTC) Received: from nm7-vm3.bullet.mail.ne1.yahoo.com (nm7-vm3.bullet.mail.ne1.yahoo.com [98.138.91.137]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 377CC1153 for ; Thu, 13 Feb 2014 18:14:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=gcom1024; t=1392315133; bh=UewvLuXqp8skdCxPd2hFEFft7vVdXRQnqXsDBzOjRkg=; h=Received:Received:Received:DKIM-Signature:X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:X-Rocket-Received:Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc:Content-Transfer-Encoding:Message-Id:References:To:X-Mailer; b=N9GE5n4MWoS3PZU1heD8jy0ZpZUlX5kuXoN93kkWT7r7VHYY4lAwn1soi7Sz7NyruV7Oumc+QP/W4Hx092DxfwBs9BzAZhNTEjUuUxE1Dt9v+6TZdUmMdIVNNnvTl5fLLNVzOy25ul7BIo+jqiBhaMpbwD6k6hIWq8eJEDwpyyY= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=gcom1024; d=yahoo.com; b=ZHthms14U6d910HcMB7CmG4BUKHTRTFncCuBh0vON3OnyJEUOh9q1h/Oks4i+7Bt8ex3nz1K7MIhTkw9+guLzeGmySpm3h7cdi8/GzXCDfOI8SbFVJ4Tk4j7Qf9YovDFshBCtnMUHMWwVB1wMFnof57cchBXxcqzivvZmKvk0GY=; Received: from [98.138.100.118] by nm7.bullet.mail.ne1.yahoo.com with NNFMP; 13 Feb 2014 18:12:13 -0000 Received: from [98.138.226.61] by tm109.bullet.mail.ne1.yahoo.com with NNFMP; 13 Feb 2014 18:12:13 -0000 Received: from [127.0.0.1] by smtp212.mail.ne1.yahoo.com with NNFMP; 13 Feb 2014 18:12:13 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1392315133; bh=UewvLuXqp8skdCxPd2hFEFft7vVdXRQnqXsDBzOjRkg=; h=X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:X-Rocket-Received:Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc:Content-Transfer-Encoding:Message-Id:References:To:X-Mailer; b=4HKvyOF3R9qAucX3wpVd+2B61K0tqBsd1sW7BGizu8zbgZVWLc4xvb6iB/A5htmfleiOE/t4grpKqKf/KaFWcS0s3Xy223gLG72wNj64PfHhzSf0ay5Gpi4kq6I8dhLykQg24RWEHOmbuFKXxPepSXfD95rGU8IiUSgZZggLsD8= X-Yahoo-Newman-Id: 667586.72508.bm@smtp212.mail.ne1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: 7fcJh7AVM1mZa8BxtnezNZjoEmZHkujrLW0qVtpkNeUOmnP FT7EIULNfRyqKA.AMgSN2njoviT1vjOR1pPUiFLWMuP1gqNKLO0cJy1R4aMl a6bQaygvVXiotcLPBv8PEfPN8vUZCQBcQut9cXfX_Nl52PAOvEnqIBANCcYJ lPJNZcoUBpik7wWxqIuqGtROQQqs6YFPcpzv5LKf4waVRqpbWKS.TVPH0WM8 p4tPWQ6wgXTz1nzpJLSaX4C7dC8LQrEFq4FKpVhBHzcXuM5A28LTiylLzM8q _3l.A37RnoqZikckOq5aGQuYU4C5fLii.rDLfEpBV.NGpbtClok.LEh7QtwC mjFKsRkQRJCbeM6gVWR6us4fNGInzRZg9n_2QyeLywKuygkTG2xSK3SyvLwy __S8How6p0gjDzY4q.ONQZsGWCunTziA4z2Mzpv00syQzr2zPF0yk9_OIOMd rARDbq6_82E.cqENsc7Ja9hrU2XQx_xV6vjF7RT1f_Ctv.Rd.vMVe7bkwlXf 4sIj2M6nHdpAo4W4JkY3pRe6NOkaSc7akpd6UTRg9EW5fcJ9TPlKN1Mq310_ io._3u3MF X-Yahoo-SMTP: clhABp.swBB7fs.LwIJpv3jkWgo2NU8- X-Rocket-Received: from [10.0.102.27] (scott4long@50.242.69.61 with plain [63.250.193.228]) by smtp212.mail.ne1.yahoo.com with SMTP; 13 Feb 2014 10:12:13 -0800 PST Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.1 \(1827\)) Subject: Re: Use of contiguous physical memory in cxgbe driver From: Scott Long In-Reply-To: <20140213180736.GA34851@funkthat.com> Date: Thu, 13 Feb 2014 10:12:11 -0800 Content-Transfer-Encoding: quoted-printable Message-Id: References: <21216.22944.314697.179039@hergotha.csail.mit.edu> <201402111348.52135.jhb@freebsd.org> <201402121446.19278.jhb@freebsd.org> <21244.20212.423983.960018@hergotha.csail.mit.edu> <20140213075651.GY34851@funkthat.com> <21245.1163.754141.154430@hergotha.csail.mit.edu> <20140213180736.GA34851@funkthat.com> To: John-Mark Gurney X-Mailer: Apple Mail (2.1827) Cc: FreeBSD Net , Garrett Wollman X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 13 Feb 2014 18:14:23 -0000 On Feb 13, 2014, at 10:07 AM, John-Mark Gurney wrote: > Garrett Wollman wrote this message on Thu, Feb 13, 2014 at 12:44 = -0500: >> < said: >>=20 >>> Though we might want to keep a few mbufs reserved for receive now = that >>> you mention it... We should never get to the point where we can't >>> allocate even one frame for receive... >>=20 >> It's very easy to get to that state if the driver insists on getting >> three physically contiguous pages (which is what it takes to allocate >> a single 9k cluster) >=20 > Well, if you're using a cheap NIC that can't do scatter/gather DMA, > then you get what you pay for=85 >=20 Like I alluded to in another email, it=92s not a hard problem to address = for these =93cheap=94 cards, it=92s a deliberate design decision from FreeBSD. Scott