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Date: Fri, 17 Jan 2025 20:37:05 +0000
From: Jaegeuk Kim <jaegeuk@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net,
	linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 0/2 v6] add ioctl/sysfs to donate file-backed pages
Message-ID: <Z4q_cd5qNRjqSG8i@google.com>
References: <20250117164350.2419840-1-jaegeuk@kernel.org>
 <Z4qb9Pv-mEQZrrXc@casper.infradead.org>
 <Z4qmF2n2pzuHqad_@google.com>
 <Z4qpurL9YeCHk5v2@casper.infradead.org>
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In-Reply-To: <Z4qpurL9YeCHk5v2@casper.infradead.org>

On 01/17, Matthew Wilcox wrote:
> On Fri, Jan 17, 2025 at 06:48:55PM +0000, Jaegeuk Kim wrote:
> > > I don't understand how this is different from MADV_COLD.  Please
> > > explain.
> > 
> > MADV_COLD is a vma range, while this is a file range. So, it's more close to
> > fadvise(POSIX_FADV_DONTNEED) which tries to reclaim the file-backed pages
> > at the time when it's called. The idea is to keep the hints only, and try to
> > reclaim all later when admin expects system memory pressure soon.
> 
> So you're saying you want POSIX_FADV_COLD?

Yeah, the intention looks similar like marking it cold and paging out later.