From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from hancock.sc.steeleye.com (stat1.steeleye.com [65.114.3.130]) by dsl2.external.hp.com (Postfix) with ESMTP id AF11848AA for ; Thu, 8 Apr 2004 11:43:58 -0600 (MDT) Received: from midgard.sc.steeleye.com (midgard.sc.steeleye.com [172.17.6.40]) by hancock.sc.steeleye.com (8.11.6/linuxconf) with ESMTP id i38Hhja29865; Thu, 8 Apr 2004 13:43:45 -0400 Subject: Re: [parisc-linux] rmap: parisc __flush_dcache_page From: James Bottomley To: Andrea Arcangeli In-Reply-To: <20040408171017.GJ31667@dualathlon.random> References: <1081435237.1885.144.camel@mulgrave> <20040408151415.GB31667@dualathlon.random> <1081438124.2105.207.camel@mulgrave> <20040408153412.GD31667@dualathlon.random> <1081439244.2165.236.camel@mulgrave> <20040408161610.GF31667@dualathlon.random> <1081441791.2105.295.camel@mulgrave> <20040408171017.GJ31667@dualathlon.random> Content-Type: text/plain Date: 08 Apr 2004 12:43:45 -0500 Message-Id: <1081446226.2105.402.camel@mulgrave> Mime-Version: 1.0 Cc: Hugh Dickins , Linux Kernel , parisc-linux@parisc-linux.org List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2004-04-08 at 12:10, Andrea Arcangeli wrote: > I said above per-arch abstraction, a per-arch abstraction isn't an irq > safe spinlock, we cannot add an irq safe spinlock there, it'd be too bad > for all the common archs that don't need to walk those lists (actually > trees in my -aa tree) from irq context. I think we agree on the abstraction thing. I was more wondering what you thought was so costly about an irq safe spinlock as opposed to an ordinary one? Is there something adding to this cost I don't know about? i.e. should we be thinking about something like RCU or phased tree approach to walking the mapping lists? James