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	Mon, 13 Oct 2025 21:56:30 +0000
Date: Mon, 13 Oct 2025 22:56:30 +0100
From: Matthew Wilcox <willy@infradead.org>
To: Barry Song <21cnbao@gmail.com>
Cc: netdev@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, Barry Song <v-songbaohua@oppo.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Eric Dumazet <edumazet@google.com>,
	Kuniyuki Iwashima <kuniyu@google.com>,
	Paolo Abeni <pabeni@redhat.com>,
	Willem de Bruijn <willemb@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Simon Horman <horms@kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Suren Baghdasaryan <surenb@google.com>,
	Michal Hocko <mhocko@suse.com>,
	Brendan Jackman <jackmanb@google.com>,
	Johannes Weiner <hannes@cmpxchg.org>, Zi Yan <ziy@nvidia.com>,
	Yunsheng Lin <linyunsheng@huawei.com>,
	Huacai Zhou <zhouhuacai@oppo.com>
Subject: Re: [RFC PATCH] mm: net: disable kswapd for high-order network
 buffer allocation
Message-ID: <aO11jqD6jgNs5h8K@casper.infradead.org>
References: <20251013101636.69220-1-21cnbao@gmail.com>
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In-Reply-To: <20251013101636.69220-1-21cnbao@gmail.com>

On Mon, Oct 13, 2025 at 06:16:36PM +0800, Barry Song wrote:
> On phones, we have observed significant phone heating when running apps
> with high network bandwidth. This is caused by the network stack frequently
> waking kswapd for order-3 allocations. As a result, memory reclamation becomes
> constantly active, even though plenty of memory is still available for network
> allocations which can fall back to order-0.

I think we need to understand what's going on here a whole lot more than
this!

So, we try to do an order-3 allocation.  kswapd runs and ... succeeds in
creating order-3 pages?  Or fails to?

If it fails, that's something we need to sort out.

If it succeeds, now we have several order-3 pages, great.  But where do
they all go that we need to run kswapd again?