netdev - [PATCH v3 0/1] mm/page_alloc: dynamic watermark boosting

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Message-ID: <tencent_DEB3B993C801A1D507C53976DEA7F6940D05@qq.com>
Date: Mon,  5 Jan 2026 19:59:42 +0800
From: wujing <realwujing@...com>
To: Andrew Morton <akpm@...ux-foundation.org>,
	Vlastimil Babka <vbabka@...e.cz>
Cc: Matthew Wilcox <willy@...radead.org>,
	Lance Yang <lance.yang@...ux.dev>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Michal Hocko <mhocko@...e.com>,
	Brendan Jackman <jackmanb@...gle.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Zi Yan <ziy@...dia.com>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org,
	Qiliang Yuan <yuanql9@...natelecom.cn>,
	wujing <realwujing@...com>
Subject: [PATCH v3 0/1] mm/page_alloc: dynamic watermark boosting

This is v3 of the auto-tuning patch, addressing feedback from Vlastimil Babka,
Andrew Morton, and Matthew Wilcox.

Major shift in v3:
Following Vlastimil's suggestion, this version abandons the direct modification
of min_free_kbytes. Instead, it leverages the existing watermark_boost
infrastructure. This approach is more idiomatic as it:
- Avoids conflicts with administrative sysctl settings.
- Only affects specific zones experiencing pressure.
- Utilizes standard kswapd logic for natural decay after reclamation.

Responses to Vlastimil Babka's feedback:
> "Were they really packet drops observed? AFAIK the receive is deferred to non-irq 
> context if those atomic allocations fail, it shouldn't mean a drop."
In our high-concurrency production environment, we observed that while the 
network stack tries to defer processing, persistent GFP_ATOMIC failures 
eventually lead to NIC-level drops due to RX buffer exhaustion.

> "As for the implementation I'd rather not be changing min_free_kbytes directly... 
> We already have watermark_boost to dynamically change watermarks"
Agreed and implemented in v3.

Changes in v3:
- Replaced min_free_kbytes modification with watermark_boost calls.
- Removed all complex decay/persistence logic from v2, relying on kswapd's 
  standard behavior.
- Maintained the 10-second debounce mechanism.
- Engaged netdev@ community as requested by Andrew Morton.

Thanks for the thoughtful reviews!

wujing (1):
  mm/page_alloc: auto-tune watermarks on atomic allocation failure

 mm/page_alloc.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

-- 
2.39.5