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Date: Thu, 1 Feb 2024 10:29:54 +0000
From: Mel Gorman <mgorman@techsingularity.net>
To: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: akpm@linux-foundation.org, vbabka@suse.cz, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mm: compaction: limit the suitable target page order
 to be less than cc->order
Message-ID: <20240201102954.e65g2q3twdtxhjzc@techsingularity.net>
References: <afcd9377351c259df7a25a388a4a0d5862b986f4.1705928395.git.baolin.wang@linux.alibaba.com>
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In-Reply-To: <afcd9377351c259df7a25a388a4a0d5862b986f4.1705928395.git.baolin.wang@linux.alibaba.com>

On Mon, Jan 22, 2024 at 09:01:53PM +0800, Baolin Wang wrote:
> It can not improve the fragmentation if we isolate the target free pages
> exceeding cc->order, especially when the cc->order is less than pageblock_order.
> For example, suppose the pageblock_order is MAX_ORDER (size is 4M) and cc->order
> is 2M THP size, we should not isolate other 2M free pages to be the migration
> target, which can not improve the fragmentation.
> 
> Moreover this is also applicable for large folio compaction.
> 
> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>

Acked-by: Mel Gorman <mgorman@techsingularity.net>

-- 
Mel Gorman
SUSE Labs