From: Paul Menzel <pmenzel@molgen.mpg.de>
To: Dave Young <dyoung@redhat.com>, Michal Hocko <mhocko@kernel.org>
Cc: linux-pci@vger.kernel.org, "Jörg Rödel" <joro@8bytes.org>,
"x86@kernel.org" <x86@kernel.org>,
kexec@lists.infradead.org,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
iommu@lists.linux-foundation.org, kasong@redhat.com,
lijiang@redhat.com, "Donald Buczek" <buczek@molgen.mpg.de>
Subject: Re: Crash kernel with 256 MB reserved memory runs into OOM condition
Date: Wed, 4 Sep 2019 12:10:55 +0200 [thread overview]
Message-ID: <bf02ab7f-4b59-5da0-5f76-f1f9ba5762ea@molgen.mpg.de> (raw)
In-Reply-To: <20190813025441.GA2979@dhcp-128-65.nay.redhat.com>
[-- Attachment #1: Type: text/plain, Size: 2632 bytes --]
Dear Dave,
Thank you for your replies.
On 2019-08-13 04:54, Dave Young wrote:
> On 08/13/19 at 10:46am, Dave Young wrote:
>> On 08/13/19 at 10:43am, Dave Young wrote:
>>> On 08/12/19 at 11:50am, Michal Hocko wrote:
>>>> On Mon 12-08-19 11:42:33, Paul Menzel wrote:
>>>>> On a Dell PowerEdge R7425 with two AMD EPYC 7601 (total 128 threads) and
>>>>> 1 TB RAM, the crash kernel with 256 MB of space reserved crashes.
>>>>>
>>>>> Please find the messages of the normal and the crash kernel attached.
>>>>
>>>> You will need more memory to reserve for the crash kernel because ...
>>>>
>>>>> [ 4.548703] Node 0 DMA free:484kB min:4kB low:4kB high:4kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:568kB managed:484kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>> [ 4.573612] lowmem_reserve[]: 0 125 125 125
>>>>> [ 4.577799] Node 0 DMA32 free:1404kB min:1428kB low:1784kB high:2140kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:15720kB writepending:0kB present:261560kB managed:133752kB mlocked:0kB kernel_stack:2496kB pagetables:0kB bounce:0kB free_pcp:212kB local_pcp:212kB free_cma:0kB
>>>>
>>>> ... the memory is really depleted and nothing to be reclaimed (no anon.
>>>> file pages) Look how tht free memory is below min watermark (node zone DMA has
>>>> lowmem protection for GFP_KERNEL allocation).
>>>
>>> We found similar issue on our side while working on kdump on SME enabled
>>> systemd. Kairui is working on some patches.
>>>
>>> Actually on those SME/SEV enabled machines, swiotlb is enabled
>>> automatically so at least we need extra 64M+ memory for kdump other
>>> than the normal expectation.
>>>
>>> Can you check if this is also your case?
>>
>> The question is to Paul, also it would be always good to cc kexec mail
>> list for kexec and kdump issues.
As already replied <kexec@lists.infradead.org> was CCed in my original
message, but the list put it under moderation.
> Looks like hardware iommu is used, maybe you do not enable SME?
Do you mean AMD Secure Memory Encryption? I do not think, we use that.
> Also replace maxcpus=1 with nr_cpus=1 can save some memory, can have a
> try.
Thank you for this suggestion. That fixed it indeed, and the reserved
memory can stay at 256 MB. (The parameter names are a little unintuitive –
I guess due to historical reasons.
Kind regards,
Paul
[1]: https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt
[-- Attachment #2: S/MIME Cryptographic Signature --]
[-- Type: application/pkcs7-signature, Size: 5174 bytes --]
next prev parent reply other threads:[~2019-09-04 10:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 9:42 Crash kernel with 256 MB reserved memory runs into OOM condition Paul Menzel
2019-08-12 9:50 ` Michal Hocko
2019-08-12 9:59 ` Paul Menzel
2019-08-13 2:43 ` Dave Young
2019-08-13 2:46 ` Dave Young
2019-08-13 2:54 ` Dave Young
2019-09-04 10:10 ` Paul Menzel [this message]
2019-08-15 17:00 ` Messages to kexec@ get moderated (was: Crash kernel with 256 MB reserved memory runs into OOM condition) Paul Menzel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bf02ab7f-4b59-5da0-5f76-f1f9ba5762ea@molgen.mpg.de \
--to=pmenzel@molgen.mpg.de \
--cc=buczek@molgen.mpg.de \
--cc=dyoung@redhat.com \
--cc=iommu@lists.linux-foundation.org \
--cc=joro@8bytes.org \
--cc=kasong@redhat.com \
--cc=kexec@lists.infradead.org \
--cc=lijiang@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=mhocko@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).