From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: Populating multiple ptes at fault time From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org In-Reply-To: <48D17E75.80807@redhat.com> References: <48D142B2.3040607@goop.org> <48D17E75.80807@redhat.com> Content-Type: text/plain Date: Fri, 19 Sep 2008 10:45:03 -0700 Message-Id: <1221846303.8077.27.camel@pasglop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Avi Kivity Cc: Jeremy Fitzhardinge , Nick Piggin , Hugh Dickens , Linux Memory Management List , Linux Kernel Mailing List , Avi Kivity , Andrew Morton , Rik van Riel List-ID: On Wed, 2008-09-17 at 15:02 -0700, Avi Kivity wrote: > Jeremy Fitzhardinge wrote: > > Minor faults are easier; if the page already exists in memory, we should > > just create mappings to it. If neighbouring pages are also already > > present, then we can can cheaply create mappings for them too. > > > > > > One problem is the accessed bit. If it's unset, the shadow code cannot > make the pte present (since it has to trap in order to set the accessed > bit); if it's set, we're lying to the vm. > > This doesn't affect Xen, only kvm. Other archs too. On powerpc, !accessed -> not hashed (or not in the TLB for SW loaded TLB platforms). Ben. -- 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/ . Don't email: email@kvack.org