From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 4 Sep 2001 12:44:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 4 Sep 2001 12:44:07 -0400 Received: from are.twiddle.net ([64.81.246.98]:27013 "EHLO are.twiddle.net") by vger.kernel.org with ESMTP id ; Tue, 4 Sep 2001 12:43:56 -0400 Date: Tue, 4 Sep 2001 09:44:12 -0700 From: Richard Henderson To: Paul Mackerras Cc: David Mosberger , torvalds@transmeta.com, linux-kernel@vger.kernel.org, davem@redhat.com Subject: Re: [PATCH] avoid unnecessary cache flushes Message-ID: <20010904094412.B18163@twiddle.net> Mail-Followup-To: Paul Mackerras , David Mosberger , torvalds@transmeta.com, linux-kernel@vger.kernel.org, davem@redhat.com In-Reply-To: <15247.29338.3671.548678@cargo.ozlabs.ibm.com> <20010903131436.A16069@twiddle.net> <15251.59286.154267.431231@napali.hpl.hp.com> <20010903134125.B16069@twiddle.net> <15252.13330.652765.959658@cargo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <15252.13330.652765.959658@cargo.ozlabs.ibm.com>; from paulus@samba.org on Tue, Sep 04, 2001 at 11:53:22AM +1000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 04, 2001 at 11:53:22AM +1000, Paul Mackerras wrote: > If the page is a private page (private COW or anonymous page) then I > don't see where the kernel would be modifying the page. ptrace set breakpoint? > For alpha, the thing that my patch does that might hurt is the change > from flush_icache_page to flush_icache_range in kernel/ptrace.c. Any > comment on that? Hum. Yes. We need a way to distinguish between userspace and kernelspace icache flushes. Previously, flush_icache_page was used exclusively for userspace and flush_icache_range exclusively for kernelspace. Since I _do_ have address space numbers, I can avoid the "flush all" by allocating a new ASN for the user process. Which doesn't work for the kernel of course; there I do have to flush all. r~