From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 9 Jan 2001 20:21:51 -0200 (BRST) From: Marcelo Tosatti Subject: Re: Subtle MM bug In-Reply-To: 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" , "David S. Miller" , Rik van Riel , linux-mm@kvack.org List-ID: On Tue, 9 Jan 2001, Linus Torvalds wrote: > > On Tue, 9 Jan 2001, Marcelo Tosatti wrote: > > > > > > The second problem is that background scanning is being done > > > > unconditionally, and it should not. You end up getting all pages with the > > > > same age if the system is idle. Look at this example (2.4.1-pre1): > > > > > > I agree. However, I think that we do want to do some background scanning > > > to push out dirty pages in the background, kind of like bdflush. It just > > > shouldn't age the pages (and thus not move them to the inactive list). > > > > Actually it must age the pages, but aging should not be unconditional. > > No, I'm saying that "the background scanning" should not do the page > aging. If you age pages only when there is memory pressure/low memory, you'll have less knowledge about which pages were unused/used pages over time. > Obviously "refill_inactive()" needs to do the page aging. I'm just not at > all convinced that "background scanning" == "refill_inactive()". This is the background scanning I refer (in kswapd): /* * Do some (very minimal) background scanning. This * will scan all pages on the active list once * every minute. This clears old referenced bits * and moves unused pages to the inactive list. */ refill_inactive_scan(6, 0); -- 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/