Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751230AbcKXFXu (ORCPT ); Thu, 24 Nov 2016 00:23:50 -0500 Received: from host.buserror.net ([209.198.135.123]:55126 "EHLO host.buserror.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750720AbcKXFXs (ORCPT ); Thu, 24 Nov 2016 00:23:48 -0500 Date: Wed, 23 Nov 2016 23:23:30 -0600 From: Scott Wood To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Message-ID: <20161124052330.GA17212@home.buserror.net> References: <69b1226ce134761fd7ab81a498bdb85cd737280f.1474441302.git.christophe.leroy@c-s.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <69b1226ce134761fd7ab81a498bdb85cd737280f.1474441302.git.christophe.leroy@c-s.fr> User-Agent: Mutt/1.5.24 (2015-08-30) X-SA-Exim-Connect-IP: 50.171.225.118 X-SA-Exim-Mail-From: oss@buserror.net X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * -15 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] Subject: Re: [v3,2/3] powerpc: get hugetlbpage handling more generic X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:57:07 +0000) X-SA-Exim-Scanned: Yes (on host.buserror.net) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1488 Lines: 30 On Wed, Sep 21, 2016 at 10:11:54AM +0200, Christophe Leroy wrote: > Today there are two implementations of hugetlbpages which are managed > by exclusive #ifdefs: > * FSL_BOOKE: several directory entries points to the same single hugepage > * BOOK3S: one upper level directory entry points to a table of hugepages > > In preparation of implementation of hugepage support on the 8xx, we > need a mix of the two above solutions, because the 8xx needs both cases > depending on the size of pages: > * In 4k page size mode, each PGD entry covers a 4M bytes area. It means > that 2 PGD entries will be necessary to cover an 8M hugepage while a > single PGD entry will cover 8x 512k hugepages. > * In 16 page size mode, each PGD entry covers a 64M bytes area. It means > that 8x 8M hugepages will be covered by one PGD entry and 64x 512k > hugepages will be covers by one PGD entry. > > This patch: > * removes #ifdefs in favor of if/else based on the range sizes > * merges the two huge_pte_alloc() functions as they are pretty similar > * merges the two hugetlbpage_init() functions as they are pretty similar > > Signed-off-by: Christophe Leroy > Reviewed-by: Aneesh Kumar K.V With this patch on e6500, running the hugetlb testsuite results in the system hanging in a storm of OOM killer invocations (I'll try to debug more deeply later). This patch also changes the default hugepage size on FSL book3e from 4M to 16M. -Scott