From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx115.postini.com [74.125.245.115]) by kanga.kvack.org (Postfix) with SMTP id 135CE6B0002 for ; Thu, 21 Feb 2013 20:22:41 -0500 (EST) Date: Fri, 22 Feb 2013 11:32:35 +1100 From: David Gibson Subject: Re: [RFC PATCH -V2 05/21] powerpc: Reduce PTE table memory wastage Message-ID: <20130222003235.GJ21011@truffula.fritz.box> References: <1361465248-10867-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1361465248-10867-6-git-send-email-aneesh.kumar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="jIYo0VRlfdMI9fLa" Content-Disposition: inline In-Reply-To: <1361465248-10867-6-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Aneesh Kumar K.V" Cc: benh@kernel.crashing.org, paulus@samba.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org --jIYo0VRlfdMI9fLa Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Feb 21, 2013 at 10:17:12PM +0530, Aneesh Kumar K.V wrote: > From: "Aneesh Kumar K.V" >=20 > We now have PTE page consuming only 2K of the 64K page.This is in order to > facilitate transparent huge page support, which works much better if our = PMDs > cover 16MB instead of 256MB. >=20 > Inorder to reduce the wastage, we now have multiple PTE page fragment > from the same PTE page. This needs a much better description of what you're doing here to manage the allocations. It's certainly not easy to figure out from the code. [snip] > +#ifdef CONFIG_PPC_64K_PAGES > +typedef pte_t *pgtable_t; > +#else > typedef struct page *pgtable_t; > +#endif This looks really bogus. A pgtable_t is a pointer to PTEs on 64K, but a pointer to a struct page on 4k. --=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 --jIYo0VRlfdMI9fLa Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAlEmvKMACgkQaILKxv3ab8aRMQCeOlWmhsYrGIGG9+5J0ADAmUQL LyoAoIZQNeQEdS8G2DD4s+Ch/Z2rkEVv =dYoL -----END PGP SIGNATURE----- --jIYo0VRlfdMI9fLa-- -- 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