From: Dev Jain <dev.jain@arm.com>
To: Kiryl Shutsemau <kas@kernel.org>,
"Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Harry Yoo <harry@kernel.org>, Usama Arif <usama.arif@linux.dev>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Brendan Jackman <brendan.jackman@linux.dev>,
Zi Yan <ziy@nvidia.com>, Shakeel Butt <shakeel.butt@linux.dev>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH v3] mm: page_alloc: make defrag_mode retries follow the promoted order
Date: Mon, 19 Oct 2026 12:28:40 +0530 [thread overview]
Message-ID: <4aa14b41-9b89-494c-8825-55fffd5a541c@arm.com> (raw)
In-Reply-To: <atDMN5MoGrwJNpAj@thinkstation>
On 15/10/26 6:25 pm, Kiryl Shutsemau wrote:
> On Thu, Oct 15, 2026 at 09:16:36AM +0200, Vlastimil Babka (SUSE) wrote:
>>> And agree 7.4-rc1 with CC stable is fine. Sadly, not sure if anyone
>>> but Meta is using the feature right now.
>>
>> I thought it was there for a long time but it was only added in 2025 :) At
>> least the enterprise world is slow to adopt things, AFAICS.
>
> I was thinking to propose a patch after merge window to make defrag_mode
> default. Do you think it is too early? I don't think it is ever going
> to be truly stabilized without wider exposure.
AFAIU defrag mode is not going to improve mTHP allocation success.
I ran a synthetic benchmark faulting in lots of 64k mTHP with swap enabled,
defrag mode caused me to enter a warn_alloc (and 8 times more compact_stalls),
which didn't happen without defrag.
So perhaps bundle the default with pageblock_order eagerness etc.
>
> We also discussed with Johannes to make a stricter (defrag_mode=2?) mode
> that will not give up on fragmentation ever, but OOM instead.
>
next prev parent reply other threads:[~2026-10-19 6:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-09 12:55 Kiryl Shutsemau (Meta)
2026-10-09 14:05 ` Usama Arif
2026-10-10 22:49 ` Andrew Morton
2026-10-12 10:17 ` Kiryl Shutsemau
2026-10-12 11:40 ` Vlastimil Babka (SUSE)
2026-10-13 2:28 ` Andrew Morton
2026-10-13 17:37 ` Kiryl Shutsemau
2026-10-13 18:15 ` Vlastimil Babka (SUSE)
2026-10-14 20:29 ` Johannes Weiner
2026-10-15 7:16 ` Vlastimil Babka (SUSE)
2026-10-15 12:55 ` Kiryl Shutsemau
2026-10-15 13:53 ` Vlastimil Babka (SUSE)
2026-10-15 14:39 ` Kiryl Shutsemau
2026-10-19 6:58 ` Dev Jain [this message]
2026-10-15 12:50 ` Kiryl Shutsemau
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