From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 20 Dec 2007 11:04:21 +0900 From: KOSAKI Motohiro Subject: Re: [patch 10/20] SEQ replacement for anonymous pages In-Reply-To: <20071219084058.6ae3c531@bree.surriel.com> References: <20071219140904.9858.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20071219084058.6ae3c531@bree.surriel.com> Message-Id: <20071220082806.6F68.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: kosaki.motohiro@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lee Schermerhorn List-ID: Hi Rik-san > > > To keep the maximum amount of necessary work reasonable, we scale the > > > active to inactive ratio with the size of memory, using the formula > > > active:inactive ratio = sqrt(memory in GB * 10). > > > why do you think best formula is sqrt(GB*10)? > > please tell me if you don't mind. > > On a 1GB system, this leads to a ratio of 3 active anon > pages to 1 inactive anon page, and a maximum inactive > anon list size of 250MB. > > On a 1TB system, this leads to a ratio of 100 active anon > pages to 1 inactive anon page, and a maximum inactive > anon list size of 10GB. > > The numbers in-between looked reasonable :) thanks for your kind description. I think it make sense. and, please add comment liked blow table if you don't mind. for take more intuitive description. total return max memory value inactive anon ------------------------------------- 10MB 1 5MB 100MB 1 50MB 1GB 3 250MB 10GB 10 0.9GB 100GB 31 3GB 1TB 101 10GB 10TB 320 32GB > Basically the requirement is that the inactive anon list > is large enough that pages get a chance to be referenced > again, but small enough that the maximum amount of work > the VM needs to do is bounded to something reasonable. > > > and i have a bit worry to it works well or not on small systems. > > because it is indicate 1:1 ratio on less than 100MB memory system. > > Do you think this viewpoint? > > A 1:1 ratio simply means that the inactive anon list is > the same size as the active anon list. Page replacement > should still work fine that way. I'm sold. thanks. /kosaki -- 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/ . Don't email: email@kvack.org