From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: Active Memory Defragmentation: Our implementation & problems Message-ID: From: Mark_H_Johnson@raytheon.com Date: Wed, 4 Feb 2004 14:12:17 -0600 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: root@chaos.analogic.com Cc: Dave Hansen , linux-kernel , linux-mm , Timothy Miller , owner-linux-mm@kvack.org, Alok Mooley List-ID: Richard B. Johnson wrote: >Eventually you >get to the fact that even contiguous physical RAM doesn't >have to be contiguous and, in fact, with modern controllers >it's quite unlikely that it is. It's a sack of bits that >are uniquely addressable. Yes and no. We are using a shared memory interface on a cluster that allows us to map up to 512 Mbytes of memory from another machine. There are 16k address translation table (ATT) entries in the card, so we're allocating 32K chunks of memory per ATT. We are using the bigphysarea patch for the driver (in 2.4 kernels) only because the driver can't reliably get the chunks of RAM it is asking for. We can continue to operate the way we've been doing or get a mechanism to defragment physical RAM so the driver can continue to work a week after we rebooted the machine. --Mark H Johnson -- 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: aart@kvack.org