From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 25 Jun 2000 00:51:42 -0300 (BRST) From: Rik van Riel Subject: 2.4 / 2.5 VM plans Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: "Stephen C. Tweedie" , linux-mm@kvack.org List-ID: Hi, since I've heard some rumours of you folks having come up with nice VM ideas at USENIX and since I've been working on various VM things (and experimental 2.5 things) for the last months, maybe it's a good idea to see which of your ideas have already been put into code and to see which ideas fit together or are mutually exclusive. :) To start the discussion, here's my flameba^Wlist of ideas: 2.4: 1) re-introduce page aging, my small and simple experiments seem to indicate that page aging takes *less* cpu time than copying pages to/from highmem all the time (let alone making your applications wait for disk because we replaced the wrong page last time) 2) fix the latency problems of applications calling shrink_mmap and flushing infinite amounts of pages (mostly fixed) 3) separate page replacement (page aging) and page flushing, currently we'll happily free a referenced clean page just because the unreferenced pages haven't been flushed to disk yet ... this is very bad since the unreferenced pages often turn out to be things like executable code we could achieve this by augmenting the current MM subsystem with an inactive and scavenge list, in the process splitting shrink_mmap() into three better readable functions ... I have this mostly done 4) fix balance_dirty() to include inactive pages and have kflushd help kswapd by proactively flushing some of the inactive pages _before_ we run into trouble 5) implement some form of write throttling for VMAs so it'll be impossible for big mmap()s, etc, to competely fill memory with dirty pages regards, Rik -- The Internet is not a network of computers. It is a network of people. That is its real strength. Wanna talk about the kernel? irc.openprojects.net / #kernelnewbies http://www.conectiva.com/ http://www.surriel.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.eu.org/Linux-MM/