From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e36.co.us.ibm.com (8.12.11/8.12.11) with ESMTP id jBFLpGwx028727 for ; Thu, 15 Dec 2005 16:51:16 -0500 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by westrelay02.boulder.ibm.com (8.12.10/NCO/VERS6.8) with ESMTP id jBFLoN1f126326 for ; Thu, 15 Dec 2005 14:50:23 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11/8.13.3) with ESMTP id jBFLpFxW005262 for ; Thu, 15 Dec 2005 14:51:15 -0700 Message-ID: <43A1E551.1090403@us.ibm.com> Date: Thu, 15 Dec 2005 13:51:13 -0800 From: Matthew Dobson MIME-Version: 1.0 Subject: Re: [RFC][PATCH 0/6] Critical Page Pool References: <439FCECA.3060909@us.ibm.com> <20051214100841.GA18381@elf.ucw.cz> <43A0406C.8020108@us.ibm.com> <20051215162601.GJ2904@elf.ucw.cz> In-Reply-To: <20051215162601.GJ2904@elf.ucw.cz> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Pavel Machek Cc: linux-kernel@vger.kernel.org, andrea@suse.de, Sridhar Samudrala , Andrew Morton , Linux Memory Management List-ID: Pavel Machek wrote: >>>And as you noticed, it does not work for your original usage case, >>>because reserved memory pool would have to be "sum of all network >>>interface bandwidths * ammount of time expected to survive without >>>network" which is way too much. >> >>Well, I never suggested it didn't work for my original usage case. The >>discussion we had is that it would be incredibly difficult to 100% >>iron-clad guarantee that the pool would NEVER run out of pages. But we can >>size the pool, especially given a decent workload approximation, so as to >>make failure far less likely. > > > Perhaps you should add file in Documentation/ explaining it is not > reliable? That's a good suggestion. I will rework the patch's additions to Documentation/sysctl/vm.txt to be more clear about exactly what we're providing. >>>If you want few emergency pages for some strange hack you are doing >>>(swapping over network?), just put swap into ramdisk and swapon() it >>>when you are in emergency, or use memory hotplug and plug few more >>>gigabytes into your machine. But don't go introducing infrastructure >>>that _can't_ be used right. >> >>Well, that's basically the point of posting these patches as an RFC. I'm >>not quite so delusional as to think they're going to get picked up right >>now. I was, however, hoping for feedback to figure out how to design >>infrastructure that *can* be used right, as well as trying to find other >>potential users of such a feature. > > > Well, we don't usually take infrastructure that has no in-kernel > users, and example user would indeed be nice. > Pavel Understood. I certainly wouldn't expect otherwise. I'll see if I can get Sridhar to post his networking changes that take advantage of this. Thanks! -Matt -- 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