From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Linux-MM <linux-mm@kvack.org>
Subject: "tell us why you want to disable CONFIG_COMPACTION" --> spikes from VMs?
Date: Sat, 19 Dec 2020 19:48:58 +0100 [thread overview]
Message-ID: <CAHmME9oMB65sKa7iAFS3Ma62yf9HFQnNar2pCEjxOAw06Me3Cw@mail.gmail.com> (raw)
Hi,
In trying to debug an issue, I came across this text in the config
COMPACTION menu item:
> Compaction is the only memory management component to form
> high order (larger physically contiguous) memory blocks
> reliably. The page allocator relies on compaction heavily and
> the lack of the feature can lead to unexpected OOM killer
> invocations for high order memory requests. You shouldn't
> disable this option unless there really is a strong reason for
> it and then we would be really interested to hear about that at
> linux-mm@kvack.org.
So, here I am as requested.
My system has 64 gigs of ram. Often times when starting up VMs, with
either QEMU/KVM or with VMware, the VM will be extremely sluggish and
laggy for a little while, usually around 5 minutes. During that phase,
I see kcompact0 using 100% CPU. But other times this doesn't happen at
all. I figured I'd try removing CONFIG_COMPACTION and seeing what
happens, but then I saw your admonishment, so here I am.
Has anybody else seen this behavior?
Jason
next reply other threads:[~2020-12-19 18:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-19 18:48 Jason A. Donenfeld [this message]
2020-12-20 19:29 ` "tell us why you want to disable CONFIG_COMPACTION" --> spikes from VMs? Matthew Wilcox
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