Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 10 Dec 2001 08:50:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 10 Dec 2001 08:49:57 -0500 Received: from mpdr0.detroit.mi.ameritech.net ([206.141.239.206]:39299 "EHLO mailhost.det.ameritech.net") by vger.kernel.org with ESMTP id ; Mon, 10 Dec 2001 08:49:50 -0500 Date: Mon, 10 Dec 2001 08:47:58 -0500 (EST) From: volodya@mindspring.com Reply-To: volodya@mindspring.com To: Alan Cox cc: linux-kernel@vger.kernel.org Subject: Re: mm question In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 10 Dec 2001, Alan Cox wrote: > > How does one do the following task: obtain a bunch of free pages (around > > 300K) with physical addresses between certain bounds (more then > > 0x4000000, but it is likely this is not constant) reserver them and map to > > kernel space so that the driver can access them directly ? > > We support allocating pages below 16Mb, below 4Gb, or anywhere within RAM > on x86. If you want to within a range or your 300K must be a single 300K > block then you need to allocate it at boot time > It does not have to be contiguous. I was thinking of simply starting with the smallest address and trying to free the pages until the needed amount is available. But I have no idea how to properly do locking or force the page to be swapped out or something. As for doing this during boot time this does not seem like a good idea for two reasons: a) I need at least _two_ buffers 300K each b) the actual amount of RAM needed changes depending on video standard (this is for video capture). thanks Vladimir Dergachev - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/