From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4014F915.7060300@cyberone.com.au> Date: Mon, 26 Jan 2004 22:25:09 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [BENCHMARKS] Namesys VM patches improve kbuild References: <400F630F.80205@cyberone.com.au> <20040121223608.1ea30097.akpm@osdl.org> <16399.42863.159456.646624@laputa.namesys.com> <40105633.4000800@cyberone.com.au> <16400.63379.453282.283117@laputa.namesys.com> <4011392D.1090600@cyberone.com.au> <16401.16474.881069.437933@laputa.namesys.com> <4011C537.8040104@cyberone.com.au> <16404.63446.649110.348477@laputa.namesys.com> In-Reply-To: <16404.63446.649110.348477@laputa.namesys.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Nikita Danilov Cc: Andrew Morton , linux-mm@kvack.org List-ID: Nikita Danilov wrote: >Nick Piggin writes: > > > >[...] > > > > > But by clearing the referenced bit when below the reclaim_mapped > > threshold, you're throwing this information away. > > > > Say you have 16 mapped pages on the active list, 8 referenced, 8 not. > > You do a !reclaim_mapped scan. Your 16 pages are now in the same > > order and none are referenced. You now do a reclaim_mapped scan and > > reclaim 8 pages. 4 of them were the referenced ones, 4 were not. > > > > With my change, you would reclaim all 8 non referenced pages. > >Which is wrong, because none of them was referenced _recently_. These >pages are cold, according to the VM's notion of hotness. (Long time >probably has passed between !reclaim_mapped and reclaim_mapped scans in >your example.) > Well you'd have to admit the referenced pages are hotter, but I guess I can't argue with the numbers: it must not be very significant. I just wonder why your patch makes such an improvement. You're basically putting mapped pages to one side until reclaim_mapped, which is similar to what my patch does, right? -- 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