From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261348AbUBTRPA (ORCPT ); Fri, 20 Feb 2004 12:15:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261352AbUBTRPA (ORCPT ); Fri, 20 Feb 2004 12:15:00 -0500 Received: from fw.osdl.org ([65.172.181.6]:36804 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S261348AbUBTRO6 (ORCPT ); Fri, 20 Feb 2004 12:14:58 -0500 Date: Fri, 20 Feb 2004 09:19:45 -0800 (PST) From: Linus Torvalds To: Ingo Molnar cc: Tridge , Al Viro , Jamie Lokier , "H. Peter Anvin" , Kernel Mailing List Subject: Re: explicit dcache <-> user-space cache coherency, sys_mark_dir_clean(), O_CLEAN In-Reply-To: <20040220170438.GA19722@elte.hu> Message-ID: References: <16435.61622.732939.135127@samba.org> <20040219081027.GB4113@mail.shareable.org> <20040219163838.GC2308@mail.shareable.org> <20040219182948.GA3414@mail.shareable.org> <20040220120417.GA4010@elte.hu> <20040220170438.GA19722@elte.hu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Feb 2004, Ingo Molnar wrote: > > there's another class of problems: is it an issue that directory renames > that move this directory (higher up in the directory hierarchy of this > directory) do not invalidate the cache? In that case there's no dnotify > event either. This is one of the reasons why I worry about user-space caching. It's just damn hard to get right. It's hard in kernel space too, of course, but we've had smart people working on the dcache for years. So if we can sanely avoid duplication, that would be a good thing. Linus