From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rzrs82GpZzDqQL for ; Wed, 27 Jul 2016 20:32:12 +1000 (AEST) Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3rzrs74Xr8z9srY for ; Wed, 27 Jul 2016 20:32:11 +1000 (AEST) Message-ID: <1469612976.5978.143.camel@kernel.crashing.org> Subject: Re: _PAGE_PRESENT and _PAGE_ACCESSED From: Benjamin Herrenschmidt To: LEROY Christophe , linuxppc-dev@ozlabs.org Date: Wed, 27 Jul 2016 19:49:36 +1000 In-Reply-To: <20160726195245.Horde.xJWqCTeuxQeC7gAnGhJItg6@messagerie.si.c-s.fr> References: <20160726195245.Horde.xJWqCTeuxQeC7gAnGhJItg6@messagerie.si.c-s.fr> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2016-07-26 at 19:52 +0200, LEROY Christophe wrote: > In ppc8xx tlbmiss handler, we consider a page valid if both   > _PAGE_PRESENT and _PAGE_ACCESSED are set. > Is there any chance to have _PAGE_ACCESSED set and not _PAGE_PRESENT ? > Otherwise we could simplify the handler by considering the page valid   > only when _PAGE_ACCESSED is set When _PAGE_PRESENT is not set, the PTE becomes a swap PTE and a pile of the other bits can be repurposed, you may want to verify if _PAGE_ACCESSED is one of them. Cheers, Ben.