From owner-freebsd-current Sun Jan 26 14:26:43 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id OAA28473 for current-outgoing; Sun, 26 Jan 1997 14:26:43 -0800 (PST) Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by freefall.freebsd.org (8.8.5/8.8.5) with SMTP id OAA28444 for ; Sun, 26 Jan 1997 14:26:30 -0800 (PST) Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id WAA28837; Sun, 26 Jan 1997 22:44:28 +0100 From: Luigi Rizzo Message-Id: <199701262144.WAA28837@labinfo.iet.unipi.it> Subject: Re: exec bug To: dg@root.com Date: Sun, 26 Jan 1997 22:44:28 +0100 (MET) Cc: phk@critter.dk.tfs.com, swallace@ece.uci.edu, current@FreeBSD.ORG In-Reply-To: <199701262132.NAA08152@root.com> from "David Greenman" at Jan 26, 97 01:31:59 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-current@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > >Wouldn't it make sense for the image activator to do a couple of probes > >first to see that the data is actually available ? that way it could > >fail intelligently ? > > The problem is that determining page residency might be too high of an > overhead, but maybe not. See my last reply to Bruce. how about this: int dont_panic_just_probing= 0; ... s = splhigh(); dont_panic_just_probing = 1; ... access page at address p ... if (dont_panic_just_probing == 2 && fault_virtual_addr == p) could_not_get_the_page = 1; dont_panic_just_probing = 0; splx(p); dont_panic_just_probing is checked in the page fault handler, if set to 1 is incremented to 2, otherwise just do as it is now. Luigi