Return-Path: Received: by vger.rutgers.edu via listexpand id ; Sun, 9 Apr 2000 05:19:05 -0400 Received: by vger.rutgers.edu id ; Sun, 9 Apr 2000 05:18:53 -0400 Received: from [216.101.162.242] ([216.101.162.242]:33158 "EHLO pizda.ninka.net") by vger.rutgers.edu with ESMTP id ; Sun, 9 Apr 2000 05:16:30 -0400 Date: Sun, 9 Apr 2000 02:19:03 -0700 Message-Id: <200004090919.CAA02908@pizda.ninka.net> From: "David S. Miller" To: manfreds@colorfullife.com Cc: alan@lxorguk.ukuu.org.uk, kanoj@google.engr.sgi.com, linux-kernel@vger.rutgers.edu, linux-mm@kvack.org, torvalds@transmeta.com In-reply-to: <38F048F5.1FABC033@colorfullife.com> (message from Manfred Spraul on Sun, 09 Apr 2000 11:10:13 +0200) Subject: Re: zap_page_range(): TLB flush race References: <38F048F5.1FABC033@colorfullife.com> Sender: owner-linux-kernel@vger.rutgers.edu Content-Length: 1223 Lines: 31 Date: Sun, 09 Apr 2000 11:10:13 +0200 From: Manfred Spraul I don't understand the purpose of flush_page_to_ram(): It's a (bad) attempt to deal with virtually indexed caches which are larger than the page size of the machine. Generally, when the kernel writes to a page which potentially can subsequently accessed from user mappings, it must call flush_page_to_ram. It flushes the kernel-view page out of the caches and thus makes main memory up to date, this way when the user accesses the page from his mapping he won't see stale data if he happens to have the page mapped at a bad "virtual alias" of what the kernel maps it at. It sucks, I'd like to kill it along with flush_icache_page. I have been working a lot recently on something which is clean and hopefully can allow these things to die. But I don't want to talk more about it until I am able to come up with an implementation which I am happy with, because until that time it may as well not exist. Later, David S. Miller davem@redhat.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/