From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 25 Feb 2008 16:15:36 +0100 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: Page scan keeps touching kernel text pages Message-ID: <20080225151536.GA13358@lazybastard.org> References: <20080224144710.GD31293@lazybastard.org> <20080225150724.GF2604@shadowen.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20080225150724.GF2604@shadowen.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Andy Whitcroft Cc: =?utf-8?B?SsO2cm4=?= Engel , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Mon, 25 February 2008 15:07:24 +0000, Andy Whitcroft wrote: > On Sun, Feb 24, 2008 at 03:47:11PM +0100, JA?rn Engel wrote: > > While tracking down some unrelated bug I noticed that shrink_page_list() > > keeps testing very low page numbers (aka kernel text) until deciding > > that the page lacks a mapping and cannot get freed. Looks like a waste > > of cpu and cachelines to me. > > > > Is there a better reason for this behaviour than lack of a patch? > > shrink_page_list() would be expected to be passed pages pulled from > the active or inactive lists via isolate_lru_pages()? I would not have > expected to find the kernel text on the LRU and therefore not expect to > see it passed to shrink_page_list()? Your expectations match mine. At least someone shares my dilusions. :) > I would expect to find pages below the kernel text as real pages, and > potentially on the LRU on some architectures. Which architecture are > you seeing this? Which zones do the pages belong? 32bit x86 (run in qemu, shouldn't make a difference). Not sure about the zones. Let me rerun to check that. JA?rn -- Ninety percent of everything is crap. -- Sturgeon's Law -- 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