From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 25 Apr 2005 15:47:49 +0100 From: Christoph Hellwig Subject: returning non-ram via ->nopage, was Re: [patch] mspec driver for 2.6.12-rc2-mm3 Message-ID: <20050425144749.GA10093@infradead.org> References: <16987.39773.267117.925489@jaguar.mkp.net> <20050412032747.51c0c514.akpm@osdl.org> <20050413204335.GA17012@infradead.org> <20050424101615.GA22393@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Jes Sorensen Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Jes has this shiny new IA64 uncached foo bar whizbang driver (see the patch at http://marc.theaimsgroup.com/?l=linux-kernel&m=111416930927092&w=2), which has a nopage routine that calls remap_pfn_range from ->nopage for uncached memory that's not part of the mem map. Because ->nopage wants to return a struct page * he's allocating a normal kernel page and actually returns that one - to get the page he wants into the pagetables his does all the pagetable manipulation himself before (See the glory details of pagetable walks and modification inside a driver in the patch above). I don't think these hacks are acceptable for a driver, especially as the problem can easily be solved by calling remap_pfn_range in ->mmap - except SGI also wants node locality.. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org