From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 18 Feb 2002 22:53:45 -0300 (BRT) From: Rik van Riel Subject: Re: [RFC] Page table sharing In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: Daniel Phillips , Hugh Dickins , dmccr@us.ibm.com, Kernel Mailing List , linux-mm@kvack.org, Robert Love , mingo@redhat.co, Andrew Morton , manfred@colorfullife.com, wli@holomorphy.com List-ID: On Mon, 18 Feb 2002, Linus Torvalds wrote: > On Mon, 18 Feb 2002, Rik van Riel wrote: > > > > We'll need protection from the swapout code. > > Absolutely NOT. > > If the swapout code unshares or shares the PMD, that's a major bug. > > The swapout code doesn't need to know one way or the other, because the > swapout code never actually touches the pmd itself, it just follows the > pointers - it doesn't ever need to worry about the pmd counts at all. The swapout code can remove a page from the page table while another process is in the process of unsharing the page table. We really want to make sure that the copied-over page table doesn't point to a page which just got swapped out. regards, Rik -- "Linux holds advantages over the single-vendor commercial OS" -- Microsoft's "Competing with Linux" document http://www.surriel.com/ http://distro.conectiva.com/ -- 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/