From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 1 Nov 2006 13:46:04 -0800 From: Andrew Morton Subject: Re: Page allocator: Single Zone optimizations Message-Id: <20061101134604.fe8c89c6.akpm@osdl.org> In-Reply-To: References: <20061027190452.6ff86cae.akpm@osdl.org> <20061027192429.42bb4be4.akpm@osdl.org> <20061027214324.4f80e992.akpm@osdl.org> <20061028180402.7c3e6ad8.akpm@osdl.org> <4544914F.3000502@yahoo.com.au> <20061101182605.GC27386@skynet.ie> <20061101123451.3fd6cfa4.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Mel Gorman , Nick Piggin , KAMEZAWA Hiroyuki , linux-mm@kvack.org List-ID: On Wed, 1 Nov 2006 13:00:55 -0800 (PST) Christoph Lameter wrote: > On Wed, 1 Nov 2006, Andrew Morton wrote: > > > And hot-unplug isn't actually the interesting application. Modern Intel > > memory controllers apparently have (or will have) the ability to power down > > DIMMs. > > Plus one would want to be able to move memory out of an area where we may > have a bad DIMM. If we monitor soft ECC failures then we could also > judge a DIMM to be bad if we have a too high soft failure rate. > > If there is a hard failure and we can recover (page cache page f.e.) > then we could preemptively disable the complete DIMM. Point. > I still think that we need to generalize the approach to be > able to cover as much memory as possible. Remapping can solve some of the > issues, for others we could add additional ways to make things movable. > F.e. one could make page table pages movable by adding a back pointer to > the mm, reclaimable slab pages by adding a move function, driver > allocations could have a backpointer to the driver that would be able to > move its memory. Hmm.... Maybe generally a way to provide a > function to move data in the page struct for kernel allocations? Sounds hard. That's all Version 2 ;) (For example, I do recall working out that going from a slab-page up to a buffer_head and then reclaiming that buffer_head is basically impossible from a locking POV, but I forget the details..) -- 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