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Sun, 5 Mar 2023 22:50:49 -0500 (EST) Message-ID: <9bdeda94a7cd2ee9218d992e1da95a322ce0ec68.camel@HansenPartnership.com> Subject: Re: [LSF/MM/BPF TOPIC] Cloud storage optimizations From: James Bottomley To: Matthew Wilcox Cc: Keith Busch , Luis Chamberlain , Theodore Ts'o , lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org Date: Sun, 05 Mar 2023 22:50:48 -0500 In-Reply-To: References: <2600732b9ed0ddabfda5831aff22fd7e4270e3be.camel@HansenPartnership.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.4 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 5E2291C000D X-Rspam-User: X-Stat-Signature: 6zrb1jug9p3tqnipcnxikjqwei79idss X-HE-Tag: 1678074652-541323 X-HE-Meta: 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 WmrbWiSR +E8lrx5e7tG7ZC3rPoqpq7IpTJHRWEj2iHm2HEFcvGXyzkFun6rw/DogkkOCg8ZFZkoLvWkVs7DCVq8ickeyyUoz39xN8aRHPU9AC4b1iT7J04AhKt8860DGj923p34kh/otmKEYqtAbjcm1xR8gpjf2+tFXOW85D1AnsQa+kkb2TuFvfCN4m63DmO7x8Zrb9cD7cFW2uiEqpB9yuORG+U3fYdVeqCmO32hElW+B9/qZc1YR/J3wzB1atY/e0PMp/OiqA48YcXOu4Gk3eYUnXwJxyqFI3rS0AKkTyuLiql6Et9c96a/TQ36B1j/ymHwxejqpQiXJXNEC71ME= 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 Sat, 2023-03-04 at 16:39 +0000, Matthew Wilcox wrote: > > I fully understand that eventually we'll need to get a single large > > buffer to span discontiguous pages ... I noted that in the bit you > > cut, but I don't see why the prototype shouldn't start with > > contiguous pages. > > I disagree that this is a desirable goal.  To solve the scalability > issues we have in the VFS, we need to manage memory in larger chunks > than PAGE_SIZE.  That makes the concerns expressed in previous years > moot. Well, what is or isn't desirable in this regard can be left to a later exploration. Most of the cloud storage problems seem to be solved with a 16k block size, for which I think we'll find current compaction is good enough. I actually think we might not have a current cloud use case beyond 64k sectors. James