From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f41.google.com (mail-wm0-f41.google.com [74.125.82.41]) by kanga.kvack.org (Postfix) with ESMTP id AAC1A6B026C for ; Fri, 20 Nov 2015 03:19:02 -0500 (EST) Received: by wmvv187 with SMTP id v187so60692459wmv.1 for ; Fri, 20 Nov 2015 00:19:02 -0800 (PST) Received: from szxga01-in.huawei.com (szxga01-in.huawei.com. [58.251.152.64]) by mx.google.com with ESMTPS id a6si2546978wmh.59.2015.11.20.00.18.59 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 20 Nov 2015 00:19:01 -0800 (PST) Message-ID: <564ED708.5090405@huawei.com> Date: Fri, 20 Nov 2015 16:17:12 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: [RFC] mm: direct mapping count in /proc/meminfo is error Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Tang Chen , zhong jiang , Minchan Kim , Mel Gorman Cc: Linux MM , LKML I find the direct mapping count in /proc/meminfo is error. The value should be equal to the size of init_memory_mapping which showed in boot log. I add some print to show direct_pages_count[] immediately after init_memory_mapping(). The reason is that we double counting. Here is the log(kernel v4.4): ... [ 0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff] // called from "init_memory_mapping(0, ISA_END_ADDRESS);" [ 0.000000] [mem 0x00000000-0x000fffff] page 4k [ 0.000000] BRK [0x01ebf000, 0x01ebffff] PGTABLE [ 0.000000] BRK [0x01ec0000, 0x01ec0fff] PGTABLE [ 0.000000] BRK [0x01ec1000, 0x01ec1fff] PGTABLE [ 0.000000] init_memory_mapping: [mem 0xc3fe00000-0xc3fffffff] // called from "memory_map_top_down(ISA_END_ADDRESS, end);" [ 0.000000] [mem 0xc3fe00000-0xc3fffffff] page 1G // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) one time [ 0.000000] init_memory_mapping: [mem 0xc20000000-0xc3fdfffff] [ 0.000000] [mem 0xc20000000-0xc3fdfffff] page 1G // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) two time [ 0.000000] init_memory_mapping: [mem 0x00100000-0xbf78ffff] [ 0.000000] [mem 0x00100000-0x001fffff] page 4k [ 0.000000] [mem 0x00200000-0x3fffffff] page 2M [ 0.000000] [mem 0x40000000-0x7fffffff] page 1G [ 0.000000] [mem 0x80000000-0xbf5fffff] page 2M [ 0.000000] [mem 0xbf600000-0xbf78ffff] page 4k [ 0.000000] init_memory_mapping: [mem 0x100000000-0xc1fffffff] [ 0.000000] [mem 0x100000000-0xc1fffffff] page 1G // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) three time ... [ 0.000000] DirectMap4k: 3648 kB [ 0.000000] DirectMap2M: 2084864 kB [ 0.000000] DirectMap1G: 50331648 kB euler-linux:~ # cat /proc/meminfo | grep DirectMap DirectMap4k: 91712 kB DirectMap2M: 4093952 kB DirectMap1G: 48234496 kB total DirectMap is 48234496 + 4093952 + 91712 = 52420160kb 50331648 + 2084864 + 3648 = 52420160kb total init_memory_mapping is 50323008kb 52420160kb - 50323008kb = 2097152kb = 2G However I haven't find a better way to fix it, any ideas? Thanks, Xishi Qiu -- 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