From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from burns.conectiva (burns.conectiva [10.0.0.4]) by perninha.conectiva.com.br (Postfix) with SMTP id 0F06438C96 for ; Wed, 8 Aug 2001 16:11:13 -0300 (EST) Date: Wed, 8 Aug 2001 16:11:12 -0300 (BRST) From: Rik van Riel Subject: Re: Swapping anonymous pages In-Reply-To: <200108081729.f78HTvY06100@srcintern6.pa.dec.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Keir Fraser Cc: linux-mm@kvack.org List-ID: On Wed, 8 Aug 2001, Keir Fraser wrote: > The only reasons I can see for doing the current way are: > * keeping the reverse (physical -> virtual) mappings would eat too > much memory. > * since it's old (pre-2.4) code, perhaps noone has yet got round to > rewriting it for the new design. > > So, I'm curious to know which of the two it is (or whether the current > way was found to be "good enough"). Both ;) Even without the reverse mapping overhead (8 bytes per pte for shared pages in my current implementation) we have FAR too much pagetable overhead on large memory machines anyway. This means we need to support 2MB / 4MB pages, after which the point about reverse mappings being too much overhead pretty much becomes moot... I'm planning to implement some of this stuff for 2.5. regards, Rik -- IA64: a worthy successor to the i860. http://www.surriel.com/ http://www.conectiva.com/ http://distro.conectiva.com/ -- 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/