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d=linux-foundation.org; s=korg; t=1691789970; bh=KKpGLobAIF8HUegqWNTFJDMKzbP0/pVlV+z7f2QcPxU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=tQv9i5OPbstjA4C0wwvPncwznhOzGNf6nhbCtw/qr33UWETh6nY7OJzYZ3dcnjoz2 n3gUX2EHsBA39UTXUP/rwEMV+yznOdhciO0GOsTOwDIn42U/jrJdeYFFud2y2ALggl RTSPRDwmyYdMvzFI2w28UJwADTAMLZfKUeXscTkI= Date: Fri, 11 Aug 2023 14:39:29 -0700 From: Andrew Morton To: Mike Rapoport Cc: Kemeng Shi , pasha.tatashin@soleen.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] add page_ext_data to get client data in page_ext Message-Id: <20230811143929.79ee3231cbcdfbe43852a4bf@linux-foundation.org> In-Reply-To: <20230720053736.GM1901145@kernel.org> References: <20230718145812.1991717-1-shikemeng@huaweicloud.com> <20230719094421.GI1901145@kernel.org> <20230720053736.GM1901145@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: C2DF3140009 X-Rspam-User: X-Stat-Signature: bjw7i18eus8fts5acs4y7nkw9sza98cg X-Rspamd-Server: rspam01 X-HE-Tag: 1691789971-566910 X-HE-Meta: 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 X3UQdFMv Dx/gzJOMXJQR61HUQ0imvl7RMAB6kgNYUEyH5m0BRw/0gdyY/gw20ZcU6ALpOftlD2BAMmwUD5AbIqjuCIxxwEyfbp1yMYC+sGTWLgc/uNwvImybCQu9xdKLjjC1EgjgbmRS47AAZj+o8z/UyBxiecn+7Q0VAnSoUXlu5fqXUqMwh4jgeHEOSBfCrg36CN7nvHqeRqXlzQaG1iUNHgckyqww6LPlqVA78bEfhKBZtHmUHg7m/0/bLezxCisQQfh8GoxPyIFGvqq0+7Aa4Y93kJWsBrEqAr0O9uqoYKjsjoeXheTytYMvodhINfC+hVN95XSRuzklCX0yqqmXPF4z+P87+TI3CJbp06LFySLN2nDiFLe9PpgJPauzO01n5lxMznaFwDMTO4/XxXd6dedQTyrkqSmG4DdYGBbKY4pDrS4MItgaTlFDBX5hH/g== 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: On Thu, 20 Jul 2023 08:37:36 +0300 Mike Rapoport wrote: > Hi, > > On Thu, Jul 20, 2023 at 10:38:39AM +0800, Kemeng Shi wrote: > > > > on 7/19/2023 5:44 PM, Mike Rapoport wrote: > > > On Tue, Jul 18, 2023 at 10:58:09PM +0800, Kemeng Shi wrote: > > >> Current client get data from page_ext by adding offset which is auto > > >> generated in page_ext core and expose the data layout design insdie > > >> page_ext core. This series adds a page_ext_data to hide offset from > > >> client. Thanks! > > > > > > Implementers of page_ext_operations are anyway intimately related to > > > page_ext, so I'm not convinced this has any value. > > > > > Hi Mike, thanks for reply. I thinks page_ext_operations can be futher splited > > into public part which used by client to simply register and private part which > > only page_ext core cares and should not be accessed by client directly > > to reduce decoupling. > > It would be easier to justify changes in this series if they were a part of > the refactoring you describe here. > > > This series makes offset to be private which client > > doesn't really care to hide data layout inside page_ext core from client. > > There are some concrete gains I can list for now: > > 1. Future client cound call page_ext_data directly instead of define a > > new function like get_page_owner to get it's data. > > 2. No change to client if layout of page_ext data change. > > These should be a part of the changelog. > I added this to the [0/N]: : Benefits include: : : 1. Future clients can call page_ext_data directly instead of defining : a new function like get_page_owner to get the data. : : 2. There is no change to clients if the layout of page_ext data changes. Mike, what is your position on this patchset now? Thanks.