Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755887AbbBFOvZ (ORCPT ); Fri, 6 Feb 2015 09:51:25 -0500 Received: from mga02.intel.com ([134.134.136.20]:53731 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755631AbbBFOvT (ORCPT ); Fri, 6 Feb 2015 09:51:19 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,529,1418112000"; d="scan'208";a="648399304" From: "Kirill A. Shutemov" To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Jeff Dike Subject: [PATCHv2, RESEND 16/19] um: expose number of page table levels Date: Fri, 6 Feb 2015 16:51:01 +0200 Message-Id: <1423234264-197684-17-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: 1963 Lines: 57 We would want to use number of page table level to define mm_struct. Let's expose it as CONFIG_PGTABLE_LEVELS. Signed-off-by: Kirill A. Shutemov Acked-by: Richard Weinberger Cc: Jeff Dike 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/um/Kconfig.um | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/um/Kconfig.um b/arch/um/Kconfig.um index a7520c90f62d..5dbfe3d9107c 100644 --- a/arch/um/Kconfig.um +++ b/arch/um/Kconfig.um @@ -155,3 +155,8 @@ config MMAPPER config NO_DMA def_bool y + +config PGTABLE_LEVELS + int + default 3 if 3_LEVEL_PGTABLES + default 2 -- 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/