From: Andi Kleen <andi@firstfloor.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org
Subject: Re: [PATCH v2 1/2] mm: Uncharge poisoned pages
Date: Thu, 27 Apr 2017 13:51:23 -0700 [thread overview]
Message-ID: <87pofxk20k.fsf@firstfloor.org> (raw)
In-Reply-To: <20170427143721.GK4706@dhcp22.suse.cz> (Michal Hocko's message of "Thu, 27 Apr 2017 16:37:21 +0200")
Michal Hocko <mhocko@kernel.org> writes:
> On Tue 25-04-17 16:27:51, Laurent Dufour wrote:
>> When page are poisoned, they should be uncharged from the root memory
>> cgroup.
>>
>> This is required to avoid a BUG raised when the page is onlined back:
>> BUG: Bad page state in process mem-on-off-test pfn:7ae3b
>> page:f000000001eb8ec0 count:0 mapcount:0 mapping: (null)
>> index:0x1
>> flags: 0x3ffff800200000(hwpoison)
>
> My knowledge of memory poisoning is very rudimentary but aren't those
> pages supposed to leak and never come back? In other words isn't the
> hoplug code broken because it should leave them alone?
Yes that would be the right interpretation. If it was really offlined
due to a hardware error the memory will be poisoned and any access
could cause a machine check.
hwpoison has an own "unpoison" option (only used for debugging), which
I think handles this.
-Andi
WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <andi@firstfloor.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org
Subject: Re: [PATCH v2 1/2] mm: Uncharge poisoned pages
Date: Thu, 27 Apr 2017 13:51:23 -0700 [thread overview]
Message-ID: <87pofxk20k.fsf@firstfloor.org> (raw)
In-Reply-To: <20170427143721.GK4706@dhcp22.suse.cz> (Michal Hocko's message of "Thu, 27 Apr 2017 16:37:21 +0200")
Michal Hocko <mhocko@kernel.org> writes:
> On Tue 25-04-17 16:27:51, Laurent Dufour wrote:
>> When page are poisoned, they should be uncharged from the root memory
>> cgroup.
>>
>> This is required to avoid a BUG raised when the page is onlined back:
>> BUG: Bad page state in process mem-on-off-test pfn:7ae3b
>> page:f000000001eb8ec0 count:0 mapcount:0 mapping: (null)
>> index:0x1
>> flags: 0x3ffff800200000(hwpoison)
>
> My knowledge of memory poisoning is very rudimentary but aren't those
> pages supposed to leak and never come back? In other words isn't the
> hoplug code broken because it should leave them alone?
Yes that would be the right interpretation. If it was really offlined
due to a hardware error the memory will be poisoned and any access
could cause a machine check.
hwpoison has an own "unpoison" option (only used for debugging), which
I think handles this.
-Andi
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next prev parent reply other threads:[~2017-04-27 20:51 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-25 14:27 [PATCH v2 0/2] BUG raised when onlining HWPoisoned page Laurent Dufour
2017-04-25 14:27 ` Laurent Dufour
2017-04-25 14:27 ` [PATCH v2 1/2] mm: Uncharge poisoned pages Laurent Dufour
2017-04-25 14:27 ` Laurent Dufour
2017-04-25 23:48 ` Naoya Horiguchi
2017-04-25 23:48 ` Naoya Horiguchi
2017-04-26 1:54 ` Balbir Singh
2017-04-26 1:54 ` Balbir Singh
2017-04-26 2:34 ` Naoya Horiguchi
2017-04-26 2:34 ` Naoya Horiguchi
2017-04-26 3:45 ` Balbir Singh
2017-04-26 3:45 ` Balbir Singh
2017-04-26 4:46 ` Naoya Horiguchi
2017-04-26 4:46 ` Naoya Horiguchi
2017-04-26 8:59 ` Balbir Singh
2017-04-26 8:59 ` Balbir Singh
2017-04-28 9:32 ` Laurent Dufour
2017-04-28 9:32 ` Laurent Dufour
2017-04-27 14:37 ` Michal Hocko
2017-04-27 14:37 ` Michal Hocko
2017-04-27 20:51 ` Andi Kleen [this message]
2017-04-27 20:51 ` Andi Kleen
2017-04-28 6:07 ` Michal Hocko
2017-04-28 6:07 ` Michal Hocko
2017-04-28 7:31 ` Michal Hocko
2017-04-28 7:31 ` Michal Hocko
2017-04-28 9:17 ` Laurent Dufour
2017-04-28 9:17 ` Laurent Dufour
2017-04-28 13:48 ` Michal Hocko
2017-04-28 13:48 ` Michal Hocko
2017-05-02 14:59 ` Laurent Dufour
2017-05-02 14:59 ` Laurent Dufour
2017-05-02 18:55 ` Michal Hocko
2017-05-02 18:55 ` Michal Hocko
2017-05-03 11:34 ` Laurent Dufour
2017-05-03 11:34 ` Laurent Dufour
2017-05-04 1:21 ` Balbir Singh
2017-05-04 1:21 ` Balbir Singh
2017-05-08 10:42 ` Laurent Dufour
2017-05-08 10:42 ` Laurent Dufour
2017-05-09 1:41 ` Balbir Singh
2017-05-09 1:41 ` Balbir Singh
2017-05-08 2:58 ` Naoya Horiguchi
2017-05-08 2:58 ` Naoya Horiguchi
2017-05-09 9:18 ` Michal Hocko
2017-05-09 9:18 ` Michal Hocko
2017-05-09 22:59 ` Naoya Horiguchi
2017-05-09 22:59 ` Naoya Horiguchi
2017-04-25 14:27 ` [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Laurent Dufour
2017-04-25 14:27 ` Laurent Dufour
2017-04-26 2:10 ` Balbir Singh
2017-04-26 2:10 ` Balbir Singh
2017-04-26 3:13 ` Naoya Horiguchi
2017-04-26 3:13 ` Naoya Horiguchi
2017-04-28 2:51 ` Balbir Singh
2017-04-28 2:51 ` Balbir Singh
2017-04-28 6:30 ` Michal Hocko
2017-04-28 6:30 ` Michal Hocko
2017-04-28 6:50 ` Michal Hocko
2017-04-28 6:50 ` Michal Hocko
2017-04-28 6:51 ` Michal Hocko
2017-04-28 6:51 ` Michal Hocko
2017-05-10 7:41 ` Michal Hocko
2017-05-10 7:41 ` Michal Hocko
2018-01-17 23:03 ` Andrew Morton
2018-01-17 23:03 ` Andrew Morton
2018-01-23 18:15 ` Laurent Dufour
2018-01-23 18:15 ` Laurent Dufour
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