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From: David Hildenbrand <david@redhat.com>
To: craftfever@murena.io
Cc: akpm@linux-foundation.org, chengming.zhou@linux.dev,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	lorenzo.stoakes@oracle.com, regressions@lists.linux.dev,
	xu.xin16@zte.com.cn
Subject: Re: [Regerssion] [KSM] KSM CPU overhead in 6.16+ kernel compared to <=6.15 versions ("folio_walk_start" kernel object overhead)
Date: Mon, 13 Oct 2025 21:58:59 +0200	[thread overview]
Message-ID: <26a8f0aa-8d67-47ba-841c-2daf7010a2aa@redhat.com> (raw)
In-Reply-To: <46d26246-5bd5-43f7-b1a4-dc721f717413@airmail.cc>

On 13.10.25 21:54, craftfever wrote:
> 
> Unfortunately, yes I can reproduce it. And I thought that lockups does
> not happen anymore, but I was wrong, I booted today with 6.17.2 updated
> and KSM enabled and whole situation is back. But, it only happens, when
> scanning pages corresponding to a process with huge VM size, like
> Chromium with 1TB of virtual memory. The rest is alright. It's look
> like, that the folio_walk_start called with much higher frequency, than
> in 6.12-6.15 versions. in that version page scanning of huge VM size
> processes is pretty fast and flawless) Right now, when Chromium is
> running, I expecting constant 42% folio_walk_start and 15%
> ksm_scan_thread on 6.17.2 kernel (contrary to 1% folio_walk_start and
> even less ksm_scan_thread in 6.12-6.15). I must admin that whole system
> is not freezing, just Chromium with high CPU usage from ksmd and kernel.

What about 6.16?

-- 
Cheers

David / dhildenb



  parent reply	other threads:[~2025-10-13 19:59 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <34d27471-80a4-49f8-b6cb-f2e51518d9ea@airmail.cc>
2025-10-13 18:55 ` David Hildenbrand
     [not found]   ` <46d26246-5bd5-43f7-b1a4-dc721f717413@airmail.cc>
2025-10-13 19:58     ` David Hildenbrand [this message]
2025-10-14  7:59       ` David Hildenbrand
2025-10-13  9:22 craftfever
2025-10-13  9:52 ` David Hildenbrand
2025-10-13 10:18   ` David Hildenbrand

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