From: David Hildenbrand <david@redhat.com>
To: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Oscar Salvador <osalvador@suse.de>
Subject: Re: uninitialized pmem struct pages
Date: Tue, 5 Jan 2021 10:56:21 +0100 [thread overview]
Message-ID: <fed0a870-9cb3-8475-d0c4-b3d79abdddec@redhat.com> (raw)
In-Reply-To: <20210105074459.GR13207@dhcp22.suse.cz>
On 05.01.21 08:44, Michal Hocko wrote:
> On Mon 04-01-21 17:30:48, David Hildenbrand wrote:
>>>> Let's assume this is indeed a reserved pfn in the altmap. What's the
>>>> actual address of the memmap?
>>>
>>> Not sure what exactly you are asking for but crash says
>>> crash> kmem -p 6060000
>>> PAGE PHYSICAL MAPPING INDEX CNT FLAGS
>>> fffff8c600181800 6060000 0 0 0 fffffc0000000
>>
>> ^ this looks like it was somewhat initialized. All flags zero, nid/zone
>> set to -1 (wild guess) and thus the crash? weird
>
> Yes that made me scratch my head as well.
My best guess would be that this is indeed part of the altmap reserve
with a memmap on the altmap. Maybe these values are just leftovers on
the PMEM device (e.g., from older kernels)?
In the kernel, I cannot find anything that would initialize node/zone to
-1 only.
@Dan: Will get_dev_pagemap() return a valid dev_pagemap for pfns falling
into the altmap reserved region? I think we should also initialize the
memmap of the altmap reserved region somewhow.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-01-05 9:56 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-04 10:03 Michal Hocko
2021-01-04 10:45 ` David Hildenbrand
2021-01-04 14:26 ` Michal Hocko
2021-01-04 14:51 ` David Hildenbrand
2021-01-04 15:10 ` Michal Hocko
2021-01-04 15:15 ` David Hildenbrand
2021-01-04 15:33 ` Michal Hocko
2021-01-04 15:43 ` David Hildenbrand
2021-01-04 15:44 ` David Hildenbrand
2021-01-05 8:00 ` Michal Hocko
2021-01-05 8:16 ` Michal Hocko
2021-01-05 8:27 ` Dan Williams
2021-01-05 8:42 ` Michal Hocko
2021-01-05 8:57 ` Dan Williams
2021-01-05 9:05 ` Michal Hocko
2021-01-05 9:13 ` David Hildenbrand
2021-01-05 9:25 ` Michal Hocko
2021-01-05 9:27 ` David Hildenbrand
2021-01-04 15:59 ` Michal Hocko
2021-01-04 16:30 ` David Hildenbrand
2021-01-05 7:44 ` Michal Hocko
2021-01-05 9:56 ` David Hildenbrand [this message]
2021-01-05 5:33 ` Dan Williams
2021-01-05 7:40 ` Michal Hocko
2021-01-05 5:17 ` Dan Williams
2021-01-05 7:50 ` Michal Hocko
2021-01-05 9:16 ` David Hildenbrand
2021-01-05 9:25 ` David Hildenbrand
2021-01-05 9:33 ` Dan Williams
2021-01-05 9:37 ` David Hildenbrand
2021-01-05 9:56 ` Dan Williams
2021-01-05 9:58 ` David Hildenbrand
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