linux-kernel - Re: [RFC PATCH v2 0/8] mm: Hot page tracking and promotion infrastructure

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Message-ID: <aMGbpDJhOx7wHqpo@casper.infradead.org>
Date: Wed, 10 Sep 2025 16:39:16 +0100
From: Matthew Wilcox <willy@...radead.org>
To: Bharata B Rao <bharata@....com>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Jonathan.Cameron@...wei.com, dave.hansen@...el.com,
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Subject: Re: [RFC PATCH v2 0/8] mm: Hot page tracking and promotion
 infrastructure

On Wed, Sep 10, 2025 at 08:16:45PM +0530, Bharata B Rao wrote:
> This patchset introduces a new subsystem for hot page tracking
> and promotion (pghot) that consolidates memory access information
> from various sources and enables centralized promotion of hot
> pages across memory tiers.

Just to be clear, I continue to believe this is a terrible idea and we
should not do this.  If systems will be built with CXL (and given the
horrendous performance, I cannot see why they would be), the kernel
should not be migrating memory around like this.