From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 25 Aug 2001 12:29:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 25 Aug 2001 12:29:40 -0400 Received: from mailf.telia.com ([194.22.194.25]:31463 "EHLO mailf.telia.com") by vger.kernel.org with ESMTP id ; Sat, 25 Aug 2001 12:29:29 -0400 Message-Id: <200108251629.f7PGTiQ19557@mailf.telia.com> Content-Type: text/plain; charset="iso-8859-1" From: Roger Larsson To: Stephan von Krawczynski Subject: Re: [PATCH][RFC] simpler __alloc_pages{_limit} Date: Sat, 25 Aug 2001 18:25:19 +0200 X-Mailer: KMail [version 1.3] Cc: linux-kernel In-Reply-To: <200108242253.f7OMrbQ20401@mailf.telia.com> <200108250055.f7P0tGh28170@mailg.telia.com> <20010825135508.5afe1988.skraw@ithnet.com> In-Reply-To: <20010825135508.5afe1988.skraw@ithnet.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Saturday den 25 August 2001 13:55, Stephan von Krawczynski wrote: > On Sat, 25 Aug 2001 02:48:28 +0200 > > Roger Larsson wrote: > > Hi again, > > > > [two typos corrected from the version at linux-mm] > > [...] > > Doing this - the code started to collaps... > > __alloc_pages_limit could suddenly handle all special cases! > > (with small functional differences) > > > > Comments? > > Hi Roger, > > I tested your page against straight 2.4.9 (where it applied mostly, the > rest I did manually) and experience the following: > 1) system gets slow, even in times where plenty of free memory is > available. There must be some overhead inside. It is not unlikely because it care too much about the higher order allocations. It needs a higher order page and really tries... > 2) It does not really work around the basic problem of too > many cached pages in case of heavy filesystem action, I do get the already > known "kernel: __alloc_pages: 2-order allocation failed." by simply copying > files a lot. Is this with raiserfs and/or nfs? And without highmem support? Why is 2-order allocations needed??? Can anyone answer? Higher order allocs during normal operation is not that nice... > 3) Even in high load situations the CPU load seems to get > worse, I made it up to 7 with normal file copying on a SMP 1GHz 1GB RAM > machine. Might also be related to the higher order. Freeing too much inactive pages to satisfy the request... SMP might be a factor since the patch will go harder on the locks... > > Hm, I guess that doesn't really work as you expected. Well, I make a version that gives up on higher order allocations more quickly... But the real problem might be - why are the higher order allocations needed anyway? /RogerL -- Roger Larsson Skellefteċ Sweden