Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932351AbVKURJG (ORCPT ); Mon, 21 Nov 2005 12:09:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932360AbVKURJG (ORCPT ); Mon, 21 Nov 2005 12:09:06 -0500 Received: from silver.veritas.com ([143.127.12.111]:60000 "EHLO silver.veritas.com") by vger.kernel.org with ESMTP id S932351AbVKURJE (ORCPT ); Mon, 21 Nov 2005 12:09:04 -0500 Date: Mon, 21 Nov 2005 17:09:07 +0000 (GMT) From: Hugh Dickins X-X-Sender: hugh@goblin.wat.veritas.com To: Takashi Iwai cc: Lee Revell , Miles Lane , Andrew Morton , Linus Torvalds , Christoph Hellwig , LKML , alsa-devel Subject: Re: 2.6.15-rc1-mm2 -- Bad page state at free_hot_cold_page (in process 'aplay', page c18eef30) In-Reply-To: Message-ID: References: <1132510467.6874.144.camel@mindpipe> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-OriginalArrivalTime: 21 Nov 2005 17:09:04.0407 (UTC) FILETIME=[46825270:01C5EEBE] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1452 Lines: 34 On Mon, 21 Nov 2005, Takashi Iwai wrote: > > Now another question arises: Which is the recommended method for > mmapping RAM pages, vma nopage callback or remap_pfn_range()? > > IIRC, in the ealier versions, the former was recommended because > remap_page_range() with page-reserve was regarded as a hack. I do believe Linus (CC'ed so he can defend himself from my slanders) saw it that way for a long while. I believe he did, and still does, think it more correct to work through the intended vm_operations_struct methods. But has relented a little down the years, and now accepts that remap_pfn_range is here to stay (as much as anything stays). > But, looking through these changes, I feel that remap_pfn_range() is > better (easier and stabler) than vma nopage... I'm not going to make a recommendation: whatever suits you best. It does sometimes look like people converted from remap_pfn_range to nopage, just because they felt under pressure to do so. It is curious that your snd_pcm_mmap_status_nopage seems to have been affected and nothing else (I'd expected trouble in DRM but no sign). I've CC'ed hch also, he did have some pungent views on how you ought better to go about this. Hugh - 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/