Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756886AbbBFOyl (ORCPT ); Fri, 6 Feb 2015 09:54:41 -0500 Received: from mga09.intel.com ([134.134.136.24]:52068 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755632AbbBFOvS (ORCPT ); Fri, 6 Feb 2015 09:51:18 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,529,1418112000"; d="scan'208";a="662597509" From: "Kirill A. Shutemov" To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Martin Schwidefsky , Heiko Carstens Subject: [PATCHv2, RESEND 12/19] s390: expose number of page table levels Date: Fri, 6 Feb 2015 16:50:57 +0200 Message-Id: <1423234264-197684-13-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1423234264-197684-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1423234264-197684-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2654 Lines: 78 We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Core mm expects __PAGETABLE_{PUD,PMD}_FOLDED to be defined if these page table levels folded. Signed-off-by: Kirill A. Shutemov Cc: Martin Schwidefsky Cc: Heiko Carstens Tested-by: Guenter Roeck --- I've implemented accounting for pmd page tables as we have for pte (see mm->nr_ptes). It's requires a new counter in mm_struct: mm->nr_pmds. But the feature doesn't make any sense if an architecture has PMD level folded and it would be nice get rid of the counter in this case. The problem is that we cannot use __PAGETABLE_PMD_FOLDED in due to circular dependencies: -> -> In most cases wants to get definition of struct page and struct vm_area_struct. I've tried to split mm_struct into separate header file to be able to user there. But it doesn't fly on some architectures, like ARM: it wants mm_struct to implement tlb flushing. I don't see how to fix it without massive de-inlining or coverting a lot for inline functions to macros. This is other approach: expose number of page tables in use via Kconfig and use it in instead of __PAGETABLE_PMD_FOLDED from . --- arch/s390/Kconfig | 5 +++++ arch/s390/include/asm/pgtable.h | 2 ++ 2 files changed, 7 insertions(+) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 373cd5badf1c..f6aebcb7a0f8 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -155,6 +155,11 @@ config S390 config SCHED_OMIT_FRAME_POINTER def_bool y +config PGTABLE_LEVELS + int + default 4 if 64BIT + default 2 + source "init/Kconfig" source "kernel/Kconfig.freezer" diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index fbb5ee3ae57c..e08ec38f8c6e 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -91,7 +91,9 @@ extern unsigned long zero_page_mask; */ #define PTRS_PER_PTE 256 #ifndef CONFIG_64BIT +#define __PAGETABLE_PUD_FOLDED #define PTRS_PER_PMD 1 +#define __PAGETABLE_PMD_FOLDED #define PTRS_PER_PUD 1 #else /* CONFIG_64BIT */ #define PTRS_PER_PMD 2048 -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/