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b=mZy0IsbLOkV6NzapTbhUN5/hH4zrpbKZKs9GHER1Rnl03HauXaru5+sCjkghd0wMJ nisdNuznkuonBfuOF1kGrMXWXOVf3B2h408VTpwbFS67u8A/Sy4rbFUkTAEqTUIAj5 3kiRYEdG0xTLFRdJutjzMU2uxJiea7jxXaMwLSydaFwEC23dmdhgwHvQYrgV7Xhbjt fbSQhW08E7QnQKPKzhhvZqYCjgw9t/7Za1T1rej3ZNOcRrKZPJEyI8LhJAsMB0RsVK 326tWbIwSqPX1jfWWMKLZYMSk5hWLaLI6iWFMkSw2tx/34YQqZJZDBAs/yVfTeUj2q DcBo625c+YT2Q== Date: Mon, 10 Feb 2025 19:01:27 +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-Rspam-User: X-Rspamd-Queue-Id: A0A504001A X-Stat-Signature: k6995m5iqibrcfryor1qzuc1fik7y8zu X-Rspamd-Server: rspam03 X-HE-Tag: 1739214090-110947 X-HE-Meta: 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 lGVOSDlR aTpARjveUxPSQitoVpQ+i36SoQ+n9ZSmgG4o48qvQal0ir+UiwbstQL7P5lIKIr/FhLlOTyz+72bN0120n5DPsf9g584LDSOk3gtmvK1pEw6dy9GAYeOmKVfsmerGBls3+1p+VMpUuJmKG5Te81izK1gBghfccvVZOVKfQPocVjqeUYpqUDIPN+RniVBYVnA9q4OBbu+QVj0WGxCXGLr8Xo6NllxuaBD2tcC6fk5SWqtijCi1Kpl5yBr8i8PA8bJzALYRWfjHaiYwgnIykQEo1gW89hx2Cb5O8bXo 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, 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. > > Putting this directly in f2fs is a horrible idea. NAK.