From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com [202.81.31.141]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp08.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 835C52C00D0 for ; Fri, 3 May 2013 22:02:28 +1000 (EST) Received: from /spool/local by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 3 May 2013 22:00:01 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 42AA72CE804C for ; Fri, 3 May 2013 22:02:18 +1000 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r43C2Bgf18153506 for ; Fri, 3 May 2013 22:02:11 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r43C2HTi028762 for ; Fri, 3 May 2013 22:02:17 +1000 Date: Fri, 3 May 2013 21:54:28 +1000 From: David Gibson To: Benjamin Herrenschmidt Subject: Re: [PATCH -V7 02/10] powerpc/THP: Implement transparent hugepages for ppc64 Message-ID: <20130503115428.GW13041@truffula.fritz.box> References: <1367178711-8232-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1367178711-8232-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20130503045201.GO13041@truffula.fritz.box> <1367569143.4389.56.camel@pasglop> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="LvnU4bbuCGLV8PtK" In-Reply-To: <1367569143.4389.56.camel@pasglop> Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, "Aneesh Kumar K.V" , paulus@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --LvnU4bbuCGLV8PtK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 03, 2013 at 06:19:03PM +1000, Benjamin Herrenschmidt wrote: > On Fri, 2013-05-03 at 14:52 +1000, David Gibson wrote: > > Here, specifically, the fact that PAGE_BUSY is in PAGE_THP_HPTEFLAGS > > is likely to be bad. If the page is busy, it's in the middle of > > update so can't stably be considered the same as anything. >=20 > _PAGE_BUSY is more like a read lock. It means it's being hashed, so what > is not stable is _PAGE_HASHPTE, slot index, _ACCESSED and _DIRTY. The > rest is stable and usually is what pmd_same looks at (though I have a > small doubt vs. _ACCESSED and _DIRTY but at least x86 doesn't care since > they are updated by HW). Ok. It still seems very odd to me that _PAGE_BUSY would be in the THP version of _PAGE_HASHPTE, but not the normal one. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --LvnU4bbuCGLV8PtK Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAlGDpXQACgkQaILKxv3ab8a7/gCdHO5XO3PKrvuxj1xHqileGtEd nzQAmwSHLCB4TPuaZf2HAq7JjiFYwtvX =NaVi -----END PGP SIGNATURE----- --LvnU4bbuCGLV8PtK--