From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <40523B6C.7070409@matchmail.com> Date: Fri, 12 Mar 2004 14:36:28 -0800 From: Mike Fedyk MIME-Version: 1.0 Subject: Re: [PATCH] 2.6.4-rc2-mm1: vm-split-active-lists References: <4051D39D.80207@cyberone.com.au> <20040312193547.GD18799@mail.shareable.org> <405228DC.1010107@matchmail.com> <20040312222139.GG18799@mail.shareable.org> In-Reply-To: <20040312222139.GG18799@mail.shareable.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Jamie Lokier Cc: Nick Piggin , Mark_H_Johnson@raytheon.com, Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, m.c.p@wolk-project.de, owner-linux-mm@kvack.org, plate@gmx.tm, William Lee Irwin III List-ID: Jamie Lokier wrote: > Mike Fedyk wrote: > >>That would have other side benefits. If the anon page matches (I'm not >>calling it "!dirty" since that might have other semantics in the current >>VM) what is in swap, it can be cleaned without performing any IO. Also, >> suspending will have much less IO to perform before completion. > > > Exactly those sort of benefits. :) > > Btw, When you say "You're saying all anon memory should become > swap_cache eventually" it's worth noting that there are benefits to > doing it the other way too: speculatively pulling in pages that are > thought likely to be good for interactive response, at the expense of > pages which have been used more recently, and must remain in RAM for a > short while while they are considered in use, but aren't ranked so > highly based on some interactivity heuristics. > IIUC, the current VM loses the aging information as soon as a page is swapped out. You might be asking for a LFU list instead of a LRU list. Though, a reverse LFU (MFU -- most frequently used?) used only for swap might do what you want also... > I.e. fixing the "everything swapped out in the morning" problem by > having a long term slow rebalancing in favour of pages which seem to > be requested for interactive purposes, competing against the short > term balance of whichever pages have been used recently or are > predicted by short term readahead. > There was talk in Andrea's objrmap thread about using two LRU lists, but I forget what the benefits of that were. > Both replicating RAM pages to swap, and replicating swap or > file-backed pages to RAM can be speculative and down slowly, over the > long term, and when there is little other activity or I/O. In short, that probably would require some major surgery in the VM. Mike -- 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: aart@kvack.org