From patchwork Thu Mar 23 09:21:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Rapoport X-Patchwork-Id: 13185329 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88B7EC6FD1C for ; Thu, 23 Mar 2023 09:23:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231693AbjCWJXF (ORCPT ); Thu, 23 Mar 2023 05:23:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231405AbjCWJWl (ORCPT ); Thu, 23 Mar 2023 05:22:41 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66D8120A10; Thu, 23 Mar 2023 02:22:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E9F3F62566; Thu, 23 Mar 2023 09:22:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4FB03C433A8; Thu, 23 Mar 2023 09:22:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1679563356; bh=YegLTyBTgABVrk8X6Ho+iz90BqWsK5lqi1pUx+eF0sU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hwVWgNUmpqudVX5t/F4T7eVjm0xHfzWtg7vXKXM2ECqAoid0i5uuM9texyHvlOPEV lyJia9wrDlW0JFd9lMjQOEx8W0T5jd1+TJG7CJma6/ByrozwfR3fEJ+mMDIlvNLzwV 4q5Lcyirnh53qgBO9ZpI9gkUUf+3fLcNPWxiuxAjR4abA+WGhiQ4cIT1SEY/45ykKB w2YMBaN6+8xqLRjCoGCUnCSqFJWz3rgKIrF+qrDiwAa5EbSopDjo2gimc/UR44IViU W04N0UqyO8l9zfjlSz5/GrT+ylQg8hLZO0SHJ0FWxnUAaLATArJJIMkA+D/WKft8PF c7ZFGS6pkh14g== From: Mike Rapoport To: Andrew Morton Cc: Arnd Bergmann , Catalin Marinas , Christophe Leroy , "David S. Miller" , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , John Paul Adrian Glaubitz , "Kirill A. Shutemov" , Max Filippov , Michael Ellerman , Mike Rapoport , Rich Felker , Russell King , Will Deacon , Yoshinori Sato , Zi Yan , linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mm@kvack.org, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org Subject: [PATCH 03/14] arm64: reword ARCH_FORCE_MAX_ORDER prompt and help text Date: Thu, 23 Mar 2023 11:21:45 +0200 Message-Id: <20230323092156.2545741-4-rppt@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20230323092156.2545741-1-rppt@kernel.org> References: <20230323092156.2545741-1-rppt@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org From: "Mike Rapoport (IBM)" The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to describe this configuration option. Update both to actually describe what this option does. Signed-off-by: Mike Rapoport (IBM) Acked-by: Catalin Marinas --- arch/arm64/Kconfig | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index bab6483e4317..75af4c329224 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1487,24 +1487,24 @@ config XEN # 16K | 27 | 14 | 13 | 11 | # 64K | 29 | 16 | 13 | 13 | config ARCH_FORCE_MAX_ORDER - int "Maximum zone order" if ARM64_4K_PAGES || ARM64_16K_PAGES + int "Order of maximal physically contiguous allocations" if ARM64_4K_PAGES || ARM64_16K_PAGES default "13" if ARM64_64K_PAGES default "11" if ARM64_16K_PAGES default "10" help - The kernel memory allocator divides physically contiguous memory - blocks into "zones", where each zone is a power of two number of - pages. This option selects the largest power of two that the kernel - keeps in the memory allocator. If you need to allocate very large - blocks of physically contiguous memory, then you may need to - increase this value. + The kernel page allocator limits the size of maximal physically + contiguous allocations. The limit is called MAX_ORDER and it + defines the maximal power of two of number of pages that can be + allocated as a single contiguous block. This option allows + overriding the default setting when ability to allocate very + large blocks of physically contiguous memory is required. - We make sure that we can allocate up to a HugePage size for each configuration. - Hence we have : - MAX_ORDER = PMD_SHIFT - PAGE_SHIFT => PAGE_SHIFT - 3 + The maximal size of allocation cannot exceed the size of the + section, so the value of MAX_ORDER should satisfy - However for 4K, we choose a higher default value, 10 as opposed to 9, giving us - 4M allocations matching the default size used by generic code. + MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS + + Don't change if unsure. config UNMAP_KERNEL_AT_EL0 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT @@ -2298,4 +2298,3 @@ endmenu # "CPU Power Management" source "drivers/acpi/Kconfig" source "arch/arm64/kvm/Kconfig" -