From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx144.postini.com [74.125.245.144]) by kanga.kvack.org (Postfix) with SMTP id D04A76B0032 for ; Thu, 15 Aug 2013 22:10:09 -0400 (EDT) Message-ID: <520D89A7.7060802@cn.fujitsu.com> Date: Fri, 16 Aug 2013 10:08:39 +0800 From: Tang Chen MIME-Version: 1.0 Subject: Re: [PATCH part5 0/7] Arrange hotpluggable memory as ZONE_MOVABLE. References: <1375956979-31877-1-git-send-email-tangchen@cn.fujitsu.com> <20130812145016.GI15892@htj.dyndns.org> <5208FBBC.2080304@zytor.com> <20130812152343.GK15892@htj.dyndns.org> <52090D7F.6060600@gmail.com> <20130812164650.GN15892@htj.dyndns.org> <5209CEC1.8070908@cn.fujitsu.com> <520A02DE.1010908@cn.fujitsu.com> <520ADBBA.10501@cn.fujitsu.com> <1376593564.10300.446.camel@misato.fc.hp.com> In-Reply-To: Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: owner-linux-mm@kvack.org List-ID: To: Yinghai Lu Cc: Toshi Kani , Tejun Heo , Tang Chen , "H. Peter Anvin" , Bob Moore , Lv Zheng , "Rafael J. Wysocki" , Len Brown , Thomas Gleixner , Ingo Molnar , Andrew Morton , Thomas Renninger , Jiang Liu , Wen Congyang , Lai Jiangshan , Yasuaki Ishimatsu , Taku Izumi , Mel Gorman , Minchan Kim , "mina86@mina86.com" , "gong.chen@linux.intel.com" , Vasilis Liaskovitis , "lwoodman@redhat.com" , Rik van Riel , "jweiner@redhat.com" , Prarit Bhargava , Zhang Yanfei , "yanghy@cn.fujitsu.com" , the arch/x86 maintainers , "linux-doc@vger.kernel.org" , Linux Kernel Mailing List , Linux MM , ACPI Devel Maling List , "Luck, Tony (tony.luck@intel.com)" On 08/16/2013 04:28 AM, Yinghai Lu wrote: ...... >> >> So, we still need reordering, and put a new requirement that all earlier >> allocations must be small... >> >> I think the root of this issue is that ACPI init point is not early >> enough in the boot sequence. If it were much earlier already, the whole >> thing would have been very simple. We are now trying to workaround this >> issue in the mblock code (which itself is a fine idea), but this ACPI >> issue still remains and similar issues may come up again in future. >> >> For instance, ACPI SCPR/DBGP/DBG2 tables allow the OS to initialize >> serial console/debug ports at early boot time. The earlier it can be >> initialized, the better this feature will be. These tables are not >> currently used by Linux due to a licensing issue, but it could be >> addressed some time soon. As platforms becoming more complex& legacy >> free, the needs of ACPI tables will increase. >> >> I think moving up the ACPI init point earlier is a good direction. > > Good point. > > If we put acpi_initrd_override in BRK, and can more acpi_boot_table_init() > much early. Hi yinghai, toshi, Since I brought up this issue, it has been a long time. And there were a lot of different solutions came up. No solution is perfect enough for everyone. I have tried a lot, and most of them failed. But I think most of the things cannot be seen clearly without a real patch posted. Many good ideas came up during patch reviewing. So I think I'm going to try as many ways as possible. :) Parsing SRAT earlier is what I want to do in the very beginning indeed. And now, seems that moving the whole acpi table installation and overriding earlier will bring us much more benefits. I have tried this without moving up acpi_initrd_override in my part1 patch-set. But not in the way Yinghai mentioned above. Seeing from the code, there are 5 pages in BRK for page tables. 81 /* need 4 4k for initial PMD_SIZE, 4k for 0-ISA_END_ADDRESS */ 82 #define INIT_PGT_BUF_SIZE (5 * PAGE_SIZE) 83 RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE); By "put acpi_initrd_override in BRK", do you mean increase the BRK by default ? 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