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Date: Thu, 8 Oct 2026 12:04:25 +0200
From: Christoph Hellwig <hch@lst.de>
To: Alexandre Ghiti <alex@ghiti.fr>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Yosry Ahmed <yosry@kernel.org>, Nhat Pham <nphamcs@gmail.com>,
	Chengming Zhou <chengming.zhou@linux.dev>,
	Christoph Hellwig <hch@lst.de>, Chris Li <chrisl@kernel.org>,
	Kairui Song <kasong@tencent.com>
Subject: Re: [PATCH 0/2] mm/zswap: batch the writeback IO
Message-ID: <20261008100425.GA11357@lst.de>
References: <20261007153507.50715-1-alex@ghiti.fr>
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In-Reply-To: <20261007153507.50715-1-alex@ghiti.fr>
User-Agent: Mutt/1.5.17 (2007-11-01)

On Wed, Oct 07, 2026 at 05:34:42PM +0200, Alexandre Ghiti wrote:
> Since commit 8f29aa226f82 ("mm/swap: introduce struct swap_io_ctx"),
> reclaim merges the swap writes of folios with consecutive slots into a
> single bio, but zswap writeback still issues one IO per entry. Patch 1
> makes each zswap LRU walk batch its writeback IO. Patch 2 plugs the
> walk, so that the block layer can merge what the batch cannot.

No a zswap expert, but from the high-level perspective this looks
great.