From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f50.google.com (mail-pa0-f50.google.com [209.85.220.50]) by kanga.kvack.org (Postfix) with ESMTP id A4D6C6B0038 for ; Fri, 19 Dec 2014 02:55:04 -0500 (EST) Received: by mail-pa0-f50.google.com with SMTP id bj1so722288pad.9 for ; Thu, 18 Dec 2014 23:55:04 -0800 (PST) Received: from lgeamrelo01.lge.com (lgeamrelo01.lge.com. [156.147.1.125]) by mx.google.com with ESMTP id qi8si13477481pac.31.2014.12.18.23.55.01 for ; Thu, 18 Dec 2014 23:55:02 -0800 (PST) Message-ID: <5493D9CE.5040001@lge.com> Date: Fri, 19 Dec 2014 16:54:54 +0900 From: Gioh Kim MIME-Version: 1.0 Subject: [RFC] background zero-set page for device Content-Type: text/plain; charset=euc-kr Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, =?EUC-KR?B?wMywx8ij?= , Minchan Kim , =?EUC-KR?B?J7Howdg=?= =?EUC-KR?B?vPYn?= There was some discussion to create zero-set pages in background like this: https://lkml.org/lkml/2004/10/30/73 I'm understand that it is not good for performance. But I think it can help for a device in my platform. I'm sorry I can't tell what it is. But the device needs many zero-set pages, up to several MB, so that device driver has a loop to calls alloc_page, memset(p, 0, PAGE_SIZE) and cache flush&invalidate. And the device uses the pages and returns it to kernel. Kernel reads data in the page. In this case, memset(0) must be done. I think, if memset(0) is done at idle time, it can remove memset calling of ddk. Is there any device that needs many zero-set pages? Can backgound zero-setting page be good for the device? -- Thanks, Gioh Kim -- 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