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Thu, 12 Dec 2024 21:04:15 -0800 (PST) Date: Fri, 13 Dec 2024 00:04:10 -0500 From: Johannes Weiner To: Matthew Wilcox Cc: Jens Axboe , "Christoph Lameter (Ampere)" , Christoph Hellwig , "Darrick J. Wong" , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, clm@meta.com, linux-kernel@vger.kernel.org, kirill@shutemov.name, bfoster@redhat.com Subject: Re: [PATCHSET v6 0/12] Uncached buffered IO Message-ID: <20241213050410.GA7054@cmpxchg.org> References: <668f271f-dc44-49e1-b8dc-08e65e1fec23@kernel.dk> <36599cce-42ba-ddfb-656f-162548fdb300@gentwo.org> <20241204055241.GA7820@frogsfrogsfrogs> <04e11417-cf68-4014-a7f7-e51392352e9d@kernel.dk> <2f79ff03-48ee-54bf-b928-e9519b3edfc7@gentwo.org> <383d3adc-e939-44b2-9110-4db9b4477401@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 12DAEA0004 X-Stat-Signature: ud8939kc1494ka3dx5ycxcohw74kees4 X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1734066238-641094 X-HE-Meta: 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 w3CLcL0V 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.219782, 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 Thu, Dec 12, 2024 at 07:35:28PM +0000, Matthew Wilcox wrote: > On Thu, Dec 12, 2024 at 12:14:23PM -0700, Jens Axboe wrote: > > Like I mentioned earlier, the fact that it's cached for the duration of > > the operation is more of an implementation detail that developers need > > not worry about. What's important is that it's not cached AFTER. I still > > feel UNCACHED is the best description, but I'll change it to DONTCACHE > > for the next version just to avoid the overlap with other in-kernel > > uses. > > Regardless of the user API name, I like PG_streaming for the folio > flag name. If we're throwing names in the ring, I'm partial to PG_dropbehind. It's a term I think has been used to describe this type of behavior before; it juxtaposes nicely with readahead; it plainly names the action of what will happen to the page after the current IO operation against it has completed (i.e. pairs up with PG_reclaim).