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b=ebeRGoMYbTZd2SfuijG7tuIxqoBpjfvwIZJnfD/90W8lULSGbjjBUobyzxBQYhoOO h+qoJw8YLwP8RvzGyl3HgUFTfSpmFM9otwil+uqnndpim1jG0S3tFveQcvzR7JGApV o2iXRA10BU3x9wo5XjPlDh1t782hkJmymH28h4ey/b1NLNGtgL+htxyWC7IOhcivjy ECmioTToU65ecSINjnchVemGqfXjrs2i61bdkDy1CVorYfbKHRFBepM/ZBtxu45fyj LsOmEnysEAOp851zcnqx2A7TV8r45lKhcqDrdpPn5KuBYRV3vsx//uq5tMSiwZxFHU UDfYoQpp5j/xw== Date: Wed, 12 Feb 2025 00:39:04 +0000 From: Jaegeuk Kim To: Matthew Wilcox 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: References: <20250117164350.2419840-1-jaegeuk@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 43899160003 X-Stat-Signature: iz3i3bexy57fjbskk9edny3gidrrkddd X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1739320748-509290 X-HE-Meta: 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 9143J480 82hf+pnwgWeK97IgOgSozBMCdlY9DM2XirkEpzFPgLSpmwjRyGasdmBKxguwkAOqhZHgY90Cu/Xtlkxsf2b6hc8tw+V0QND7B33mNFvwmgCNmUxi0gpQTfjJw2DhtfezUVjwNkDn/u2OCav7ymlxMC5sMurA3PDNsy5lajgrzLI+UexND1ft2ZnlZqKtdAHify3mJ9KA/Hir2W/u1Xjvfq/CXJslpOp5SfGEgMwu1Jm7TKi2mA/OSMYUiIul06/tUqcRFF/fYYtcHql72dDdBVMW057lf7LNshDGz X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 02/10, Jaegeuk Kim wrote: > On 02/10, Matthew Wilcox wrote: > > On Mon, Feb 10, 2025 at 05:00:47PM +0000, Jaegeuk Kim wrote: > > > On 02/04, Jaegeuk Kim wrote: > > > > On 01/17, Jaegeuk Kim wrote: > > > > > 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. > > > > > > > > Kindly ping, for the feedback on the direction. If there's demand for something > > > > generalized api, I'm happy to explore. > > > > > > If there's no objection, let me push the change in f2fs and keep an eye on > > > who more will need this in general. > > > > I don't know why you're asking for direction. I gave my direction: use > > fadvise(). > > Funny, that single question didn't mean like this at all. Will take a look > how the patch looks like. Ok, it seems we can get this hint via POSIX_FADV_NOREUSE. I'll take that instead of adding a new API. Thanks. > > > > > Putting this directly in f2fs is a horrible idea. NAK.