From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f181.google.com (mail-pd0-f181.google.com [209.85.192.181]) by kanga.kvack.org (Postfix) with ESMTP id 82A186B0132 for ; Mon, 9 Dec 2013 19:11:37 -0500 (EST) Received: by mail-pd0-f181.google.com with SMTP id p10so6127228pdj.40 for ; Mon, 09 Dec 2013 16:11:37 -0800 (PST) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTP id qx4si8708464pbc.135.2013.12.09.16.11.35 for ; Mon, 09 Dec 2013 16:11:35 -0800 (PST) Date: Mon, 9 Dec 2013 16:11:34 -0800 From: Andrew Morton Subject: Re: [PATCH v3 02/23] mm/memblock: debug: don't free reserved array if !ARCH_DISCARD_MEMBLOCK Message-Id: <20131209161134.e161ddfedf284f2052cad4a5@linux-foundation.org> In-Reply-To: <1386625856-12942-3-git-send-email-santosh.shilimkar@ti.com> References: <1386625856-12942-1-git-send-email-santosh.shilimkar@ti.com> <1386625856-12942-3-git-send-email-santosh.shilimkar@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Santosh Shilimkar Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, Grygorii Strashko , Yinghai Lu , Tejun Heo On Mon, 9 Dec 2013 16:50:35 -0500 Santosh Shilimkar wrote: > Now the Nobootmem allocator will always try to free memory allocated for > reserved memory regions (free_low_memory_core_early()) without taking > into to account current memblock debugging configuration > (CONFIG_ARCH_DISCARD_MEMBLOCK and CONFIG_DEBUG_FS state). > As result if: > - CONFIG_DEBUG_FS defined > - CONFIG_ARCH_DISCARD_MEMBLOCK not defined; > - reserved memory regions array have been resized during boot > > then: > - memory allocated for reserved memory regions array will be freed to > buddy allocator; > - debug_fs entry "sys/kernel/debug/memblock/reserved" will show garbage > instead of state of memory reservations. like: > 0: 0x98393bc0..0x9a393bbf > 1: 0xff120000..0xff11ffff > 2: 0x00000000..0xffffffff > > Hence, do not free memory allocated for reserved memory regions if > defined(CONFIG_DEBUG_FS) && !defined(CONFIG_ARCH_DISCARD_MEMBLOCK). Alternatives: - disable /proc/sys/kernel/debug/memblock/reserved in this case - disable defined(CONFIG_DEBUG_FS) && !defined(CONFIG_ARCH_DISCARD_MEMBLOCK) in Kconfig. How much memory are we talking about here? If it's more than "very little" then I think either of these would be better - most users will value the extra memory over an accurate /proc/sys/kernel/debug/memblock/reserved? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org