From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.ccr.net (ccr@alogconduit1ap.ccr.net [208.130.159.16]) by kvack.org (8.8.7/8.8.7) with ESMTP id XAA18105 for ; Tue, 5 Jan 1999 23:37:06 -0500 Subject: Re: Why don't shared anonymous mappings work? References: <199901051251.FAA15706@nyx10.nyx.net> From: ebiederm+eric@ccr.net (Eric W. Biederman) Date: 05 Jan 1999 22:05:06 -0600 In-Reply-To: Colin Plumb's message of "Tue, 5 Jan 1999 05:51:52 -0700 (MST)" Message-ID: Sender: owner-linux-mm@kvack.org To: Colin Plumb Cc: linux-mm@kvack.org List-ID: Take a page map it into two processes. Swap the page out from both processes to disk. The swap address is now in the pte's. Bring that page into process 1. Dirty the page, thus causing a new swap entry to be allocated. ( The write once rule) Swap the page out of process 1. Oops process 1 and process 2 have different pte's for the same page. Since we don't have any form of reverse page table entry preventing that last case is difficult to do effciently. Eric -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org