From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f172.google.com (mail-ob0-f172.google.com [209.85.214.172]) by kanga.kvack.org (Postfix) with ESMTP id 3901D6B0038 for ; Tue, 20 Oct 2015 22:21:01 -0400 (EDT) Received: by obbda8 with SMTP id da8so29827713obb.1 for ; Tue, 20 Oct 2015 19:21:00 -0700 (PDT) Received: from unicom145.biz-email.net (unicom145.biz-email.net. [210.51.26.145]) by mx.google.com with ESMTPS id ny8si3697683oeb.25.2015.10.20.19.20.59 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 20 Oct 2015 19:21:00 -0700 (PDT) Subject: Re: [PATCH V7] mm: memory hot-add: memory can not be added to movable zone defaultly References: <1444633113-27607-1-git-send-email-liuchangsheng@inspur.com> <561E8056.7050609@suse.cz> From: Changsheng Liu Message-ID: <5626F667.9000003@inspur.com> Date: Wed, 21 Oct 2015 10:20:23 +0800 MIME-Version: 1.0 In-Reply-To: <561E8056.7050609@suse.cz> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka , akpm@linux-foundation.org, isimatu.yasuaki@jp.fujitsu.com, yasu.isimatu@gmail.com, tangchen@cn.fujitsu.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, wangnan0@huawei.com, dave.hansen@intel.com, yinghai@kernel.org, toshi.kani@hp.com, qiuxishi@huawei.com, wunan@inspur.com, yanxiaofeng@inspur.com, fandd@inspur.com, Changsheng Liu a?? 2015/10/15 0:18, Vlastimil Babka a??e??: > On 10/12/2015 08:58 AM, Changsheng Liu wrote: >> From: Changsheng Liu >> >> After the user config CONFIG_MOVABLE_NODE, >> When the memory is hot added, should_add_memory_movable() return 0 >> because all zones including ZONE_MOVABLE are empty, >> so the memory that was hot added will be assigned to ZONE_NORMAL >> and ZONE_NORMAL will be created firstly. >> But we want the whole node to be added to ZONE_MOVABLE by default. >> >> So we change should_add_memory_movable(): if the user config >> CONFIG_MOVABLE_NODE and sysctl parameter hotadd_memory_as_movable is 1 >> and the ZONE_NORMAL is empty or the pfn of the hot-added memory >> is after the end of the ZONE_NORMAL it will always return 1 >> and then the whole node will be added to ZONE_MOVABLE by default. >> If we want the node to be assigned to ZONE_NORMAL, >> we can do it as follows: >> "echo online_kernel > /sys/devices/system/memory/memoryXXX/state" >> >> By the patch, the behavious of kernel is changed by sysctl, >> user can automatically create movable memory >> by only the following udev rule: >> SUBSYSTEM=="memory", ACTION=="add", >> ATTR{state}=="offline", ATTR{state}="online" I'm sorry for replying you so late due to the busy business trip. > So just to be clear, we are adding a new sysctl, because the existing > movable_node kernel option, which is checked by movable_node_is_enabled(), and > does the same thing for non-hot-added-memory (?) cannot be reused for hot-added > memory, as that would be a potentially surprising behavior change? Correct? Then > this should be mentioned in the changelog too, and wherever "movable_node" is > documented should also mention the new sysctl. Personally, I would expect > movable_node to affect hot-added memory as well, and would be surprised that it > doesn't... I think it can let the user decides when to use this feature. The user can enable the feature when making the hot_added memory of a node movable and make the feature disable to assign the hot_added memory of the next node to ZONE_NORMAL . > >> Signed-off-by: Changsheng Liu >> Signed-off-by: Xiaofeng Yan >> Tested-by: Dongdong Fan >> Cc: Wang Nan >> Cc: Dave Hansen >> Cc: Yinghai Lu >> Cc: Tang Chen >> Cc: Yasuaki Ishimatsu >> Cc: Toshi Kani >> Cc: Xishi Qiu >> --- >> Documentation/memory-hotplug.txt | 5 ++++- >> kernel/sysctl.c | 15 +++++++++++++++ >> mm/memory_hotplug.c | 24 ++++++++++++++++++++++++ >> 3 files changed, 43 insertions(+), 1 deletions(-) >> >> diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt >> index ce2cfcf..7ac7485 100644 >> --- a/Documentation/memory-hotplug.txt >> +++ b/Documentation/memory-hotplug.txt >> @@ -277,7 +277,7 @@ And if the memory block is in ZONE_MOVABLE, you can change it to ZONE_NORMAL: >> After this, memory block XXX's state will be 'online' and the amount of >> available memory will be increased. >> >> -Currently, newly added memory is added as ZONE_NORMAL (for powerpc, ZONE_DMA). >> +Currently, newly added memory is added as ZONE_NORMAL or ZONE_MOVABLE (for powerpc, ZONE_DMA). >> This may be changed in future. >> >> >> @@ -319,6 +319,9 @@ creates ZONE_MOVABLE as following. >> Size of memory not for movable pages (not for offline) is TOTAL - ZZZZ. >> Size of memory for movable pages (for offline) is ZZZZ. >> >> +And a sysctl parameter for assigning the hot added memory to ZONE_MOVABLE is >> +supported. If the value of "kernel/hotadd_memory_as_movable" is 1,the hot added >> +memory will be assigned to ZONE_MOVABLE by default. >> >> Note: Unfortunately, there is no information to show which memory block belongs >> to ZONE_MOVABLE. This is TBD. >> diff --git a/kernel/sysctl.c b/kernel/sysctl.c >> index 19b62b5..16b1501 100644 >> --- a/kernel/sysctl.c >> +++ b/kernel/sysctl.c >> @@ -166,6 +166,10 @@ extern int unaligned_dump_stack; >> extern int no_unaligned_warning; >> #endif >> >> +#ifdef CONFIG_MOVABLE_NODE >> +extern int hotadd_memory_as_movable; >> +#endif >> + >> #ifdef CONFIG_PROC_SYSCTL >> >> #define SYSCTL_WRITES_LEGACY -1 >> @@ -1139,6 +1143,17 @@ static struct ctl_table kern_table[] = { >> .proc_handler = timer_migration_handler, >> }, >> #endif >> +/*If the value of "kernel/hotadd_memory_as_movable" is 1,the hot added >> + * memory will be assigned to ZONE_MOVABLE by default.*/ >> +#ifdef CONFIG_MOVABLE_NODE >> + { >> + .procname = "hotadd_memory_as_movable", >> + .data = &hotadd_memory_as_movable, >> + .maxlen = sizeof(int), >> + .mode = 0644, >> + .proc_handler = proc_dointvec, >> + }, >> +#endif >> { } >> }; >> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 26fbba7..eca5512 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -37,6 +37,11 @@ >> >> #include "internal.h" >> >> +/*If the global variable value is 1, >> + * the hot added memory will be assigned to ZONE_MOVABLE by default >> + */ >> +int hotadd_memory_as_movable; >> + >> /* >> * online_page_callback contains pointer to current page onlining function. >> * Initially it is generic_online_page(). If it is required it could be >> @@ -1190,6 +1195,9 @@ static int check_hotplug_memory_range(u64 start, u64 size) >> /* >> * If movable zone has already been setup, newly added memory should be check. >> * If its address is higher than movable zone, it should be added as movable. >> + * And if system config CONFIG_MOVABLE_NODE and set the sysctl parameter >> + * "hotadd_memory_as_movable" and added memory does not overlap the zone >> + * before MOVABLE_ZONE,the memory will be added as movable. >> * Without this check, movable zone may overlap with other zone. >> */ >> static int should_add_memory_movable(int nid, u64 start, u64 size) >> @@ -1197,6 +1205,22 @@ static int should_add_memory_movable(int nid, u64 start, u64 size) >> unsigned long start_pfn = start >> PAGE_SHIFT; >> pg_data_t *pgdat = NODE_DATA(nid); >> struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE; >> + struct zone *pre_zone = pgdat->node_zones + (ZONE_MOVABLE - 1); >> + /* >> + * The system configs CONFIG_MOVABLE_NODE to assign a node >> + * which has only movable memory,so the hot-added memory should >> + * be assigned to ZONE_MOVABLE by default, >> + * but the function zone_for_memory() assign the hot-added memory >> + * to ZONE_NORMAL(x86_64) by default.Kernel does not allow to >> + * create ZONE_MOVABLE before ZONE_NORMAL,So if the value of >> + * sysctl parameter "hotadd_memory_as_movable" is 1 >> + * and the ZONE_NORMAL is empty or the pfn of the hot-added memory >> + * is after the end of ZONE_NORMAL >> + * the hot-added memory will be assigned to ZONE_MOVABLE. >> + */ >> + if (hotadd_memory_as_movable >> + && (zone_is_empty(pre_zone) || zone_end_pfn(pre_zone) <= start_pfn)) >> + return 1; >> >> if (zone_is_empty(movable_zone)) >> return 0; >> > . > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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