From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 02 Oct 2002 17:48:01 -0500 From: Dave McCracken Subject: Re: [PATCH] Snapshot of shared page tables Message-ID: <183710000.1033598881@baldur.austin.ibm.com> In-Reply-To: <15771.30104.815144.546550@argo.ozlabs.ibm.com> References: <45850000.1033570655@baldur.austin.ibm.com> <15771.30104.815144.546550@argo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Mackerras Cc: Linux Memory Management , Linux Kernel List-ID: --On Thursday, October 03, 2002 08:39:20 +1000 Paul Mackerras wrote: > Interesting. I notice that you are using the _PAGE_RW bit in the > PMDs. Are you relying on the hardware to do anything with that bit, > or is it only used by software? > > (If you are relying on the hardware to do something different when > _PAGE_RW is clear in the PMD, then your approach isn't portable.) Yes, I am relying on the hardware. I was under the impression that it was pretty much universal that making the pmd read-only would make the hardware treat all ptes under it as read-only. This came out of a discussion on lkml last winter where this assertion was made. Do you know of a page table-based architecture that doesn't have and honor read-only protections at the pmd level? Dave McCracken ====================================================================== Dave McCracken IBM Linux Base Kernel Team 1-512-838-3059 dmccr@us.ibm.com T/L 678-3059 -- 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/