Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755691AbbKRMps (ORCPT ); Wed, 18 Nov 2015 07:45:48 -0500 Received: from mail-yk0-f182.google.com ([209.85.160.182]:34424 "EHLO mail-yk0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752988AbbKRMpq (ORCPT ); Wed, 18 Nov 2015 07:45:46 -0500 MIME-Version: 1.0 In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1CBD539B@AcuExch.aculab.com> References: <063D6719AE5E284EB5DD2968C1650D6D1CBD539B@AcuExch.aculab.com> Date: Wed, 18 Nov 2015 20:45:45 +0800 Message-ID: Subject: Re: [PATCH] usb: gadget: Add the console support for usb-to-serial port From: Baolin Wang To: David Laight Cc: Andy Shevchenko , Felipe Balbi , Greg Kroah-Hartman , "r.baldyga@samsung.com" , "fabio.estevam@freescale.com" , Philip Oberstaller , Peter Hurley , "scottwood@freescale.com" , Mark Brown , USB , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2170 Lines: 58 On 18 November 2015 at 20:05, David Laight wrote: > From: Baolin Wang >> Sent: 18 November 2015 10:45 >> On 18 November 2015 at 17:32, Andy Shevchenko wrote: >> > On Wed, Nov 18, 2015 at 4:15 AM, Baolin Wang wrote: >> >> On 17 November 2015 at 21:34, Andy Shevchenko wrote: >> >>> On Mon, Nov 16, 2015 at 9:05 AM, Baolin Wang wrote: >> >>>> It dose not work when we want to use the usb-to-serial port based >> >>>> on one usb gadget as a console. Thus this patch adds the console >> >>>> initialization to support this request. >> >>> >> > >> >>>> +#define GS_BUFFER_SIZE (4096) >> >>> Redundant parens >> >> OK. I'll remove it. >> >> >> >>>> +#define GS_CONSOLE_BUF_SIZE (2 * GS_BUFFER_SIZE) >> >>>> + >> >>>> +struct gscons_info { >> >>>> + struct gs_port *port; >> >>>> + struct tty_driver *tty_driver; >> >>>> + struct work_struct work; >> >>>> + int buf_tail; >> >>>> + char buf[GS_CONSOLE_BUF_SIZE]; >> >>> >> >>> Can't be malloced once? >> >> The 'gscons_info' structure is malloced once. >> > >> > In state of high fragmentation is quite hard to find big memory chunks. >> > I would split it to two allocations, though if maintainers are okay >> > with your code, then I'm also okay. >> > >> >> Make sense. But I think the major memory of the 'struct gscons_info' >> is for the 'buf' member, so I still think no need to allocate it 2 >> times. > > It may be worth just reducing GS_BUFFER_SIZE slightly so that the gscons_info > structure itself is less than 8k. > If you can't get 2 adjacent pages then a lot of things will fail. > But its allocation is called in early booting time, I think there are not many memory fragments now. > David > -- Baolin.wang Best Regards -- 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/