From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from wli by holomorphy with local (Exim 3.34 #1 (Debian)) id 175ZiE-0007RJ-00 for ; Wed, 08 May 2002 15:15:06 -0700 Date: Wed, 8 May 2002 15:15:06 -0700 From: William Lee Irwin III Subject: [RFC] tabulating page->virtual on highmem Message-ID: <20020508221506.GL15756@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Description: brief message Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org List-ID: The size of the kmap pool appears to dictate the number of distinct values of page->virtual. Maintaining an index into the pool would seem to provide superior space behavior, as the index need not be of full machine word precision. Furthermore, no auxiliary lookup would appear to be required as the kmap pool is virtually contiguous and so the virtual address could be calculated from base virtual address of the kmap pool and the index into the pool. For architectures using page->virtual for page_address() calculation this technique does not apply, and so page->virtual would then need to be maintained as is, or at least retain enough precision for a full page frame number. I don't have my heart set on this but I thought I'd at least throw the idea out where its desirability (and potential implementations) could be discussed. Cheers, Bill -- 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/