From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx158.postini.com [74.125.245.158]) by kanga.kvack.org (Postfix) with SMTP id E63526B0038 for ; Wed, 24 Jul 2013 06:09:19 -0400 (EDT) Message-ID: <51EFA873.9050300@cn.fujitsu.com> Date: Wed, 24 Jul 2013 18:12:03 +0800 From: Tang Chen MIME-Version: 1.0 Subject: Re: [PATCH 13/21] x86, acpi: Try to find SRAT in firmware earlier. References: <1374220774-29974-1-git-send-email-tangchen@cn.fujitsu.com> <1374220774-29974-14-git-send-email-tangchen@cn.fujitsu.com> <20130723204949.GR21100@mtj.dyndns.org> In-Reply-To: <20130723204949.GR21100@mtj.dyndns.org> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: tglx@linutronix.de, mingo@elte.hu, hpa@zytor.com, akpm@linux-foundation.org, trenn@suse.de, yinghai@kernel.org, jiang.liu@huawei.com, wency@cn.fujitsu.com, laijs@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, mgorman@suse.de, minchan@kernel.org, mina86@mina86.com, gong.chen@linux.intel.com, vasilis.liaskovitis@profitbricks.com, lwoodman@redhat.com, riel@redhat.com, jweiner@redhat.com, prarit@redhat.com, zhangyanfei@cn.fujitsu.com, yanghy@cn.fujitsu.com, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org On 07/24/2013 04:49 AM, Tejun Heo wrote: > On Fri, Jul 19, 2013 at 03:59:26PM +0800, Tang Chen wrote: ...... >> + for (pos = 0; >> + pos< acpi_gbl_root_table_list.current_table_count; >> + pos++) { >> + if (!ACPI_COMPARE_NAME >> + (&(acpi_gbl_root_table_list.tables[pos].signature), >> + signature)) > > Hohumm... creative formatting. Can't you just cache the tables > pointer in a local variable with short name and avoid the creativity? OK, followed. > >> + continue; >> + >> + memcpy(out_desc,&acpi_gbl_root_table_list.tables[pos], >> + sizeof(struct acpi_table_desc)); >> + >> + return_ACPI_STATUS(AE_OK); >> + } >> + >> + return_ACPI_STATUS(AE_NOT_FOUND); > > Also, if we already know that SRAT is what we want, I wonder whether > it'd be simpler to store the location of SRAT somewhere instead of > trying to be generic with the early processing. Do you mean get the SRAT's address without touching any ACPI global variables, such as acpi_gbl_root_table_list ? The physical addresses of all tables is stored in RSDT (Root System Description Table), which is the root table. We need to parse RSDT to get SRAT address. Using acpi_gbl_root_table_list is very convenient. The initialization of acpi_gbl_root_table_list is using acpi_os_map_memory(), so it can be done before init_mem_mapping() and relocate_initrd(). With acpi_gbl_root_table_list initialized, we can iterate it and find SRAT easily. Otherwise, we have to do the same procedure to parse RSDT, and find SRAT, which I don't think could be any simpler. I think reuse the existing acpi_gbl_root_table_list code is better. Thanks. -- 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