From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754587Ab2CGKsa (ORCPT ); Wed, 7 Mar 2012 05:48:30 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:46726 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751092Ab2CGKs3 convert rfc822-to-8bit (ORCPT ); Wed, 7 Mar 2012 05:48:29 -0500 Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes To: "Barry Song" , "Cong Wang" Cc: m.szyprowski@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, workgroup.linux@csr.com, "Barry Song" Subject: Re: [PATCH v3] MM: CMA: add a simple kernel module as the helper to test CMA References: <1331090098-25097-1-git-send-email-Barry.Song@csr.com> <4F56E0AC.8070501@gmail.com> Date: Wed, 07 Mar 2012 11:48:24 +0100 MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT From: "Michal Nazarewicz" Message-ID: In-Reply-To: <4F56E0AC.8070501@gmail.com> User-Agent: Opera Mail/11.61 (Linux) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On 03/07/2012 11:14 AM, Barry Song wrote: >> Any write request to /dev/cma_test will let the module to allocate memory from >> CMA, for example: >> >> 1st time >> $ echo 1024> /dev/cma_test >> will require cma_test to request 1MB(1024KB) >> 2nd time >> $ echo 2048> /dev/cma_test >> will require cma_test to request 2MB(2048KB) >> >> Any read request to /dev/cma_test will let the module to free the 1st valid >> memory from CMA, for example: >> >> 1st time >> $ cat /dev/cma_test >> will require cma_test to free the 1MB allocated in the first write request >> 2nd time >> $ cat /dev/cma_test >> will require cma_test to free the 2MB allocated in the second write request On Wed, 07 Mar 2012 05:14:36 +0100, Cong Wang wrote: > Any reason why using /dev not /proc or /sys? Because /proc is for processes and /sys is for stable, documented APIs. If anything, debugfs might make some sense, but since the module needs struct device anyway, it can just register a misc device, which is simpler and does not require debugfs to be compiled. -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +------------------ooO--(_)--Ooo--