From: Kiryl Shutsemau <kas@kernel.org>
To: Dev Jain <dev.jain@arm.com>
Cc: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>,
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: Wed, 21 Oct 2026 10:33:41 +0100 [thread overview]
Message-ID: <atiCG2iPrHwDznSZ@thinkstation> (raw)
In-Reply-To: <4aa14b41-9b89-494c-8825-55fffd5a541c@arm.com>
On Mon, Oct 19, 2026 at 12:28:40PM +0530, Dev Jain wrote:
>
>
> 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.
Could you share the benchmark? I would like to play with it.
Which THP defrag setting, and was the range MADV_HUGEPAGE?
With the default "madvise" and no MADV_HUGEPAGE, a 64k fault cannot
reclaim and does not wake kswapd.
How is your system setup?
> So perhaps bundle the default with pageblock_order eagerness etc.
What do you mean by pageblock_order eagerness?
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2026-10-21 9:33 UTC|newest]
Thread overview: 16+ 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
2026-10-21 9:33 ` Kiryl Shutsemau [this message]
2026-10-15 12:50 ` Kiryl Shutsemau
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