From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755873AbaHFHPD (ORCPT ); Wed, 6 Aug 2014 03:15:03 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:33569 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755853AbaHFHPA (ORCPT ); Wed, 6 Aug 2014 03:15:00 -0400 From: "Aneesh Kumar K.V" To: Mel Gorman , Hugh Dickins Cc: Sasha Levin , "linux-mm\@kvack.org" , Andrew Morton , Dave Jones , LKML , "Kirill A. Shutemov" , Peter Zijlstra , Rik van Riel , Johannes Weiner , Cyrill Gorcunov , linuxppc-dev@ozlabs.org Subject: Re: mm: BUG in unmap_page_range In-Reply-To: <20140805144439.GW10819@suse.de> References: <53DD5F20.8010507@oracle.com> <20140805144439.GW10819@suse.de> User-Agent: Notmuch/0.18.1 (http://notmuchmail.org) Emacs/24.3.91.1 (x86_64-unknown-linux-gnu) Date: Wed, 06 Aug 2014 12:44:45 +0530 Message-ID: <871tsudr8a.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14080607-0260-0000-0000-0000000A6C73 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mel Gorman writes: > From d0c77a2b497da46c52792ead066d461e5111a594 Mon Sep 17 00:00:00 2001 > From: Mel Gorman > Date: Tue, 5 Aug 2014 12:06:50 +0100 > Subject: [PATCH] mm: Remove misleading ARCH_USES_NUMA_PROT_NONE > > ARCH_USES_NUMA_PROT_NONE was defined for architectures that implemented > _PAGE_NUMA using _PROT_NONE. This saved using an additional PTE bit and > relied on the fact that PROT_NONE vmas were skipped by the NUMA hinting > fault scanner. This was found to be conceptually confusing with a lot of > implicit assumptions and it was asked that an alternative be found. > > Commit c46a7c81 "x86: define _PAGE_NUMA by reusing software bits on the > PMD and PTE levels" redefined _PAGE_NUMA on x86 to be one of the swap > PTE bits and shrunk the maximum possible swap size but it did not go far > enough. There are no architectures that reuse _PROT_NONE as _PROT_NUMA > but the relics still exist. > > This patch removes ARCH_USES_NUMA_PROT_NONE and removes some unnecessary > duplication in powerpc vs the generic implementation by defining the types > the core NUMA helpers expected to exist from x86 with their ppc64 equivalent. > The unification for ppc64 is less than ideal because types do not exist > that the "generic" code expects to. This patch works around the problem > but it would be preferred if the powerpc people would look at this to see > if they have opinions on what might suit them better. > > Signed-off-by: Mel Gorman > --- > arch/powerpc/include/asm/pgtable.h | 55 ++++++++------------------------------ > arch/x86/Kconfig | 1 - > include/asm-generic/pgtable.h | 35 ++++++++++++------------ > init/Kconfig | 11 -------- > 4 files changed, 29 insertions(+), 73 deletions(-) > .... > - > #define pmdp_set_numa pmdp_set_numa > static inline void pmdp_set_numa(struct mm_struct *mm, unsigned long addr, > pmd_t *pmdp) > @@ -109,16 +71,21 @@ static inline void pmdp_set_numa(struct mm_struct *mm, unsigned long addr, > return; > } > > -#define pmd_mknonnuma pmd_mknonnuma > -static inline pmd_t pmd_mknonnuma(pmd_t pmd) > +/* > + * Generic NUMA pte helpers expect pteval_t and pmdval_t types to exist > + * which was inherited from x86. For the purposes of powerpc pte_basic_t is > + * equivalent > + */ > +#define pteval_t pte_basic_t > +#define pmdval_t pmd_t > +static inline pteval_t pte_flags(pte_t pte) > { > - return pte_pmd(pte_mknonnuma(pmd_pte(pmd))); > + return pte_val(pte) & PAGE_PROT_BITS; PAGE_PROT_BITS don't get the _PAGE_NUMA and _PAGE_PRESENT. I will have to check further to find out why the mask doesn't include _PAGE_PRESENT. > } > > -#define pmd_mknuma pmd_mknuma > -static inline pmd_t pmd_mknuma(pmd_t pmd) > +static inline pteval_t pmd_flags(pte_t pte) > { static inline pmdval_t ? > - return pte_pmd(pte_mknuma(pmd_pte(pmd))); > + return pmd_val(pte) & PAGE_PROT_BITS; > } > -aneesh