From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 28 Jul 2001 13:26:48 -0700 (PDT) From: Linus Torvalds Subject: Re: 2.4.8-pre1 and dbench -20% throughput In-Reply-To: <01072822131300.00315@starship> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Daniel Phillips Cc: Marcelo Tosatti , linux-mm@kvack.org, Rik van Riel , Andrew Morton , Mike Galbraith , Steven Cole , Roger Larsson List-ID: On Sat, 28 Jul 2001, Daniel Phillips wrote: > > Here is what I think is happening on a typical burst of small, non-page > aligned reads: > > - Page is read the 1st time: age = 2, inactive > - Page is read the second time: age = 5, active > - Two more reads immediately on the same page: age = 11 No. We only mark the page referenced when we read it, we don't actually increment the age. The _aging_ is only done by the actual scanning routines. At least that's how it should work. A quick grep for who does "age_page_up()" shows that it is only done by refill_inactive_scan(). (page_launder() doesn't need to do it, because it already knows the age is zero on the inactive list, so it just sets the age). Maybe the problem is that use-once works on accesses, not on ages? Linus -- 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/