linux-kernel - Re: [PATCH V2] mm:memory hot-add: memory can not been added to movable zone

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Wed, 26 Aug 2015 08:38:49 +0800
From:	Changsheng Liu <liuchangsheng@...pur.com>
To:	Yasuaki Ishimatsu <yasu.isimatu@...il.com>
CC:	<akpm@...ux-foundation.org>, <isimatu.yasuaki@...fujitsu.com>,
	<vbabka@...e.cz>, <linux-mm@...ck.org>,
	<linux-kernel@...r.kernel.org>, <yanxiaofeng@...pur.com>,
	<fandd@...pur.com>, Changsheng Liu <liuchangcheng@...pur.com>
Subject: Re: [PATCH V2] mm:memory hot-add: memory can not been added to
 movable zone

First, thanks very much for your review, I will update codes according 
to your suggestion

On 2015/8/25 21:12, Yasuaki Ishimatsu wrote:
> On Thu, 20 Aug 2015 03:28:05 -0400
> Changsheng Liu <liuchangsheng@...pur.com> wrote:
>
>> From: Changsheng Liu <liuchangcheng@...pur.com>
>>
>> When memory is hot added, should_add_memory_movable() always returns 0
>> because the movable zone is empty, so the memory that was hot added will
>> add to the normal zone even if we want to remove the memory.
>>
>> So we change should_add_memory_movable(): if the user config
>> CONFIG_MOVABLE_NODE it will return 1 when the movable zone is empty.
>>
>> Reviewed-by: Andrew Morton <akpm@...ux-foundation.org>
>> Signed-off-by: Changsheng Liu <liuchangcheng@...pur.com>
>> Tested-by: Dongdong Fan <fandd@...pur.com>
>> ---
>>   mm/memory_hotplug.c |    3 +--
>>   1 files changed, 1 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index 26fbba7..ff658f2 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -1199,8 +1199,7 @@ static int should_add_memory_movable(int nid, u64 start, u64 size)
>>   	struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
>>   
>>   	if (zone_is_empty(movable_zone))
>> -		return 0;
>> -
>> +		return IS_ENABLED(CONFIG_MOVABLE_NODE);
>>   	if (movable_zone->zone_start_pfn <= start_pfn)
>>   		return 1;
> Currently, kernel allows to create ZONE_MOVABLE after ZONE_NORMAL as follows:
>   PFN low                                 high
>         ---|-------------|-------------|---
>              ZONE_NORMAL   ZONE_MOVABLE
>
> But kernel does not allow to create ZONE_MOVABLE before ZONE_NORMAL as follows:
>   PFN low                                 high
>         ---|-------------|-------------|---
>              ZONE_MOVABLE  ZONE_NORMAL
>
> Also, kernel does not allow to create ZONE_MOVABLE in ZOME_NORMAL as follows:
>   PFN low                                              high
>         ---|-------------|-------------|-------------|---
>              ZONE_NORMAL   ZONE_MOVABLE  ZONE_NORMAL
>
> So should_add_memory_movable() checks them.
>
> Accoring to your patch, when movable_zone is empty, the hot added memory is
> always managed to ZONE_MOVABLE. It means that ZONE_MOVALBE will puts before/in
> ZONE_NORMAL.
>
> You must prevent from creating ZONE_MOVABLE before/in ZONE_NORMAL.
>
> Thanks,
> Yasuaki Ishimatsu
>
>>   
>> -- 
>> 1.7.1
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@...ck.org.  For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
>> Don't email: <a href=mailto:"dont@...ck.org"> email@...ck.org </a>
> .
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/