From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f181.google.com (mail-we0-f181.google.com [74.125.82.181]) by kanga.kvack.org (Postfix) with ESMTP id 3308C6B0071 for ; Tue, 1 Apr 2014 17:37:24 -0400 (EDT) Received: by mail-we0-f181.google.com with SMTP id q58so6808661wes.40 for ; Tue, 01 Apr 2014 14:37:23 -0700 (PDT) Received: from mail.zytor.com (terminus.zytor.com. [2001:1868:205::10]) by mx.google.com with ESMTPS id g15si10602100wiw.22.2014.04.01.14.37.19 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 01 Apr 2014 14:37:20 -0700 (PDT) Message-ID: <533B313E.5000403@zytor.com> Date: Tue, 01 Apr 2014 14:35:58 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH 0/5] Volatile Ranges (v12) & LSF-MM discussion fodder References: <1395436655-21670-1-git-send-email-john.stultz@linaro.org> <20140401212102.GM4407@cmpxchg.org> In-Reply-To: <20140401212102.GM4407@cmpxchg.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner , John Stultz Cc: LKML , Andrew Morton , Android Kernel Team , Robert Love , Mel Gorman , Hugh Dickins , Dave Hansen , Rik van Riel , Dmitry Adamushko , Neil Brown , Andrea Arcangeli , Mike Hommey , Taras Glek , Jan Kara , KOSAKI Motohiro , Michel Lespinasse , Minchan Kim , "linux-mm@kvack.org" On 04/01/2014 02:21 PM, Johannes Weiner wrote: > > Either way, optimistic volatile pointers are nowhere near as > transparent to the application as the above description suggests, > which makes this usecase not very interesting, IMO. > ... however, I think you're still derating the value way too much. The case of user space doing elastic memory management is more and more common, and for a lot of those applications it is perfectly reasonable to either not do system calls or to have to devolatilize first. -hpa -- 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: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751976AbaDAVhc (ORCPT ); Tue, 1 Apr 2014 17:37:32 -0400 Received: from terminus.zytor.com ([198.137.202.10]:37069 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751635AbaDAVhb (ORCPT ); Tue, 1 Apr 2014 17:37:31 -0400 Message-ID: <533B313E.5000403@zytor.com> Date: Tue, 01 Apr 2014 14:35:58 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Johannes Weiner , John Stultz CC: LKML , Andrew Morton , Android Kernel Team , Robert Love , Mel Gorman , Hugh Dickins , Dave Hansen , Rik van Riel , Dmitry Adamushko , Neil Brown , Andrea Arcangeli , Mike Hommey , Taras Glek , Jan Kara , KOSAKI Motohiro , Michel Lespinasse , Minchan Kim , "linux-mm@kvack.org" Subject: Re: [PATCH 0/5] Volatile Ranges (v12) & LSF-MM discussion fodder References: <1395436655-21670-1-git-send-email-john.stultz@linaro.org> <20140401212102.GM4407@cmpxchg.org> In-Reply-To: <20140401212102.GM4407@cmpxchg.org> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/01/2014 02:21 PM, Johannes Weiner wrote: > > Either way, optimistic volatile pointers are nowhere near as > transparent to the application as the above description suggests, > which makes this usecase not very interesting, IMO. > ... however, I think you're still derating the value way too much. The case of user space doing elastic memory management is more and more common, and for a lot of those applications it is perfectly reasonable to either not do system calls or to have to devolatilize first. -hpa