Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261657AbUJ0Fku (ORCPT ); Wed, 27 Oct 2004 01:40:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261656AbUJ0Fkt (ORCPT ); Wed, 27 Oct 2004 01:40:49 -0400 Received: from fw.osdl.org ([65.172.181.6]:15300 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S261652AbUJ0Fkn (ORCPT ); Wed, 27 Oct 2004 01:40:43 -0400 Date: Tue, 26 Oct 2004 22:33:35 -0700 From: Andrew Morton To: Andrea Arcangeli Cc: nickpiggin@yahoo.com.au, riel@redhat.com, linux-kernel@vger.kernel.org Subject: Re: lowmem_reserve (replaces protection) Message-Id: <20041026223335.6a1dad18.akpm@osdl.org> In-Reply-To: <20041027044445.GV14325@dualathlon.random> References: <417DCFDD.50606@yahoo.com.au> <20041027005425.GO14325@dualathlon.random> <417F025F.5080001@yahoo.com.au> <20041027022920.GS14325@dualathlon.random> <417F0FA2.4090800@yahoo.com.au> <20041027032338.GU14325@dualathlon.random> <417F1746.2080607@yahoo.com.au> <20041026204308.73ee438b.akpm@osdl.org> <20041027044445.GV14325@dualathlon.random> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1044 Lines: 28 Andrea Arcangeli wrote: > > So after allocating the highmem pages we invoke kswapd > again Nope. We don't wake kswapd until the lower zones are below pages_low as well. Then we rebalance all the zones which are below pages_high. As I say: run a workload mix and monitor /proc/vmstat: pgscan_kswapd_high pgscan_kswapd_normal pgscan_kswapd_dma These should be increasing at rates which are proportional to their size, if most allocations have __GFP_HIGHMEM. The lower-zone protection thing means that the scanning rate really should be proportional to (zone size - (protection from __GFP_HIGHMEM allocations)), but it's not too far off at present. The balancing of the zone scanning rates is subtle and easy to break. As is the balancing of that against slab scanning. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/