From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 1 Nov 2005 20:02:49 +0100 From: Ingo Molnar Subject: Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19 Message-ID: <20051101190249.GA16738@elte.hu> References: <20051030235440.6938a0e9.akpm@osdl.org> <20051101144622.GC9911@elte.hu> <200511011233.36713.rob@landley.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200511011233.36713.rob@landley.net> Sender: owner-linux-mm@kvack.org Return-Path: To: Rob Landley Cc: Mel Gorman , Nick Piggin , "Martin J. Bligh" , Andrew Morton , kravetz@us.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, lhms-devel@lists.sourceforge.net List-ID: * Rob Landley wrote: > On Tuesday 01 November 2005 08:46, Ingo Molnar wrote: > > how will the 100% solution handle a simple kmalloc()-ed kernel buffer, > > that is pinned down, and to/from which live pointers may exist? That > > alone can prevent RAM from being removable. > > Would you like to apply your "100% or nothing" argument to the virtual > memory management subsystem and see how it sounds in that context? > (As an argument that we shouldn't _have_ one?) that would be comparing apples to oranges. There is a big difference between "VM failures under high load", and "failure of VM functionality for no user-visible reason". The fragmentation problem here has nothing to do with pathological workloads. It has to do with 'unlucky' allocation patterns that pin down RAM areas which thus become non-removable. The RAM module will be non-removable for no user-visible reason. Possible under zero load, and with lots of free RAM otherwise. Ingo -- 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