From: zhenwei pi <pizhenwei@bytedance.com>
To: David Hildenbrand <david@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
virtualization@lists.linux.dev
Cc: mst@redhat.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com,
akpm@linux-foundation.org
Subject: Re: Re: [RFC 0/3] Improve memory statistics for virtio balloon
Date: Tue, 16 Apr 2024 11:20:19 +0800 [thread overview]
Message-ID: <c88b999f-39f9-4771-bb28-b6b0cd5ba22c@bytedance.com> (raw)
In-Reply-To: <ee1ac0fb-daf7-4aea-b07e-f8879b6b860b@redhat.com>
On 4/15/24 23:01, David Hildenbrand wrote:
> On 15.04.24 10:41, zhenwei pi wrote:
>> Hi,
>>
>> When the guest runs under critial memory pressure, the guest becomss
>> too slow, even sshd turns D state(uninterruptible) on memory
>> allocation. We can't login this VM to do any work on trouble shooting.
>>
>> Guest kernel log via virtual TTY(on host side) only provides a few
>> necessary log after OOM. More detail memory statistics are required,
>> then we can know explicit memory events and estimate the pressure.
>>
>> I'm going to introduce several VM counters for virtio balloon:
>> - oom-kill
>> - alloc-stall
>> - scan-async
>> - scan-direct
>> - reclaim-async
>> - reclaim-direct
>
> IIUC, we're only exposing events that are already getting provided via
> all_vm_events(), correct?
>
Yes, all of these counters come from all_vm_events(). The 'alloc-stall'
is summary of several classes of alloc-stall. please see '[RFC 2/3]
virtio_balloon: introduce memory allocation stall counter'.
> In that case, I don't really see a major issue. Some considerations:
>
> (1) These new events are fairly Linux specific.
>
> PSWPIN and friends are fairly generic, but HGTLB is also already fairly
> Linux specific already. OOM-kills don't really exist on Windows, for
> example. We'll have to be careful of properly describing what the
> semantics are.
>
I also notice FreeBSD supports virtio balloon for a long time, 'OOM
kill' is used on FreeBSD too.(LINK:
https://klarasystems.com/articles/exploring-swap-on-freebsd/)
> (2) How should we handle if Linux ever stops supporting a certain event
> (e.g., major reclaim rework). I assume, simply return nothing like we
> currently would for VIRTIO_BALLOON_S_HTLB_PGALLOC without
> CONFIG_HUGETLB_PAGE.
>
Luckily, virtio balloon stats schema is tag-value style. This way would
be safe enough.
Suggestions in patch [1-3] are good, I'll fix them in the next version
if this series is acceptable.
--
zhenwei pi
prev parent reply other threads:[~2024-04-16 3:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-15 8:41 [RFC 0/3] Improve memory statistics for virtio balloon zhenwei pi
2024-04-15 8:41 ` [RFC 1/3] virtio_balloon: introduce oom-kill invocations zhenwei pi
2024-04-15 15:04 ` David Hildenbrand
2024-04-15 8:41 ` [RFC 2/3] virtio_balloon: introduce memory allocation stall counter zhenwei pi
2024-04-15 15:04 ` David Hildenbrand
2024-04-15 8:41 ` [RFC 3/3] virtio_balloon: introduce memory scan/reclaim info zhenwei pi
2024-04-15 15:06 ` David Hildenbrand
2024-04-15 15:01 ` [RFC 0/3] Improve memory statistics for virtio balloon David Hildenbrand
2024-04-16 3:20 ` zhenwei pi [this message]
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=c88b999f-39f9-4771-bb28-b6b0cd5ba22c@bytedance.com \
--to=pizhenwei@bytedance.com \
--cc=akpm@linux-foundation.org \
--cc=david@redhat.com \
--cc=jasowang@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mst@redhat.com \
--cc=virtualization@lists.linux.dev \
--cc=xuanzhuo@linux.alibaba.com \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).