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Bergsten" To: "'Christoph Hellwig'" , "'Matthew Wilcox'" Cc: "'Hannes Reinecke'" , "'Vlastimil Babka'" , "'Hannes Reinecke'" , "'Boris Pismenny'" , "'John Fastabend'" , "'Jakub Kicinski'" , "'Sagi Grimberg'" , , , , "'Harry Yoo'" , References: <27111897-0b36-4d8c-8be9-4f8bdbae88b7@suse.cz> <7439cb2f-6a97-494b-aa10-e9bebb218b58@suse.de> In-Reply-To: Subject: RE: Networking people smell funny and make poor life choices Date: Wed, 12 Mar 2025 11:28:50 -0700 Message-ID: <052801db937c$9bbf12a0$d33d37e0$@thebergstens.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 16.0 thread-index: AQI2rUWeLygajSlNpi7nOHx73cja5QH+C8IvAd0w/QUCBlqL4QM6XMyIAn2avhICzfEg4wKgxvSGAjQyxh8Ce7EXuQFi0EC+sgC+5wA= Content-Language: en-us X-Provags-ID: V03:K1:dcMVW0pDz5E1JPOonU9qWaZvIh+IDuHLVFneVIlFdETc33dVveN co1twA9Ugo5PZKV/k+r4WR/2ZVc4wvMXZO6XGkeFi3qR8cm4kSN7Er9rDAQQn2OpKfUQekK 1XVIeA/RxxBoaSPZ77QBYg2hW+h8FjKLg4otGWhoiv6MVVBL+FK7MuMf8u/91uNgJDY+vS8 efdi4I1cmyyDRPbTMS6NQ== UI-OutboundReport: notjunk:1;M01:P0:0C6G/a5TfTo=;EQqAowdRCwMZrivTSoBJYtVAB70 MohO5kz6kUnw5GSDAM/CFxMD1LsnEUtWNbdiLuCoG6HwUKs71eYLPumEwg7vttAekfyqxsvmn yoyCXakGb8r2kImoHPCPH5BO4xl+NgwLFE1gC3Cl/DAx0vJhzNIoOQQKEWiLAw5pGkzLbSI2k Fq1aDkD7QOrIYo7jQeaFpjGW+5heRtbNQJSGTlzZLmnlLlOf55cyaNWdGjLOJafmaNpq7yB5a DOJnpuW6Mb1fZB3jxZL726qcb1r/KEa7PY/HoboN1qWhCtx9YX99E6HPXB0yqq6bttx1g0BMw KAfp3C97/s9f3m32aEHw8mY7te7l4uFSxsg3GN5KwmNhQVsN9HqOVHqJBxJAIf/KN9dhJIQgH I0AehCPc9QFzGessG6jBIjrluBIOTX8RsjAlUUKTZzMCER+N3jXHtkDd3ahIRWS2YagPjNkMt zwGuF2rVA2/2n2h/1LPzs9gUPWnYWh1fDFD/BAsROwdtCkDqzpxvUT00uZ4k4VbCiZ+wnMpGi HX6Pz5h1xmJRmMBnEfR/G8V+KTtZQzthdxOj+nv6Ss0/j5arjKb+oew/UbrB4gamF+rvBuHG8 kAh3HPBuy6aYOWTfFFeIS8gOnRkzbsZraudh71vqJs5HWzPegzX8Nc8+6+Uw2WOdHXWZICtCV eAOYkhvsQcq2k/O226/TBfcJTQqw9G8BwBh3YrC0ehi9aJm4GqhJWsNC7VIug65nKKWL16HYF XY8FDND5BHs3HH64jKaJNak+6uYMdc3BMLxmNHt7nRG3laA1WLNCdKxk2SuDRqY9EalOvX5s+ X6Q3u2IfAK41xywS4dedXzALf109cVCy5JKvp8ZQeurBlUZ+tTOqcxb208N2D8a8ATPXNEIC6 demkZsPEOZ8+3au0HVs/+EERrBUqHaUNmwoDGbsibhM9i1EnUavo/alh6fdxiG4vSMBi9V8zc Tq0dmAIaXlAh9ecICjV8z1A7dILM5mOAAAK9GwWkA4Y+QfQfVEZtaBP8vnk9w+co1ZTjhQkyD ulSc6wutq/im9ZUiTcPEkBC02RLDaDg4buqO3nqUosSQdL//d9HUNVywgCYh4c0QrHeVIH8yY MhqEU3pB4NtY5G6eHPLJD/lMMbWDhqQMx55ikTf0HxnH08fXQKoCb41ylk3tp/JI2Q5U30q+Y yRC8TKoPslhu5WDIA3w0TBpb5iWpVEmGsVSgcAAbIOCwTbWh2tWvQkyt6NCOxmlF0UWI3cswI +pnlU1UC3HMIRENDatsfARyqIrHmOc2y9og83Bmc0/v0zHSM389u55phBqoyMoQH0cuIcuoRZ bx2mMKpSUEQa3RF2uJt8iaPSrAhHCIgZk2GeoKEzqde7J/sSgNUUK4uLyw9dSlrOw/HGuowvr 4wpFqVb+jK1dzpRg== X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 6BC5718000D X-Stat-Signature: qou34yr7q35xgw8mabzzzdhr8ngb1ejy X-HE-Tag: 1741804145-718537 X-HE-Meta: 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 UQI1fnML 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.165960, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: OK another "unnecessary" old-timer storage/network story/disruption to = your otherwise relevant discussions (thank the subject line). If you're = too busy, just don't read it. =F0=9F=98=8A Around 1985, Gene Amdahl founded a company called Andor. Its original = purpose (as was with everything Gene did) was to build the smallest = plug-compatible mainframe. When it was designed, someone noted it had = no physical room for the humongous "Bus and Tag" cables needed for = peripherals, so Gene raised a bit more money and started a storage = project too. When the Loma Prieta earthquake happened in 1989, PG&E, the local = utility, lost the datacenter containing all of the information needed to = repair their utilities, so the service people had to do this from = memory. The Public Utilities Commission didn't find this terribly = funny, so they said PG&E had to create a second datacenter out of the = area immediately and have backups there within about 24 hours, shorter = as time went on. So, they shut down the primary site every night, = dumped to tape, then drove it up to Sacramento where these were = restored. They named this CTAM for "Chevy Truck Access Method." Somehow Gene and friends heard about this and, as they already had a = processor, device simulation and devices, if they added some sort of = networking interface, they could have a local unit and a remote unit = doing this backup, eliminating the truck. BTW the "front end" storage = group all came from Memorex. The "back end" group mostly from Amdahl. This actually (somewhat) worked, and a couple of units were installed in = beta sites. Sadly, Gene ran out of money (or at least didn't accept the = terms offered) and buggered off to start yet another mainframe company = which never shipped anything. I was the last Engineering VP at Andor, so when it folded, I grabbed a = few of the people and started a similar company but for the open systems = market instead. We named it "Ark" at my wife's suggestion as was like = Noah's Ark - "disaster recovery" and "two of everything." We mostly = bootstrapped, did ship product, and were acquired by LSI Logic who were = getting beaten around the head as EMC had a remote solution, but LSI = didn't. I got about a dozen US Patents Issued and enough money to = finally buy a house in Silicon Valley. Our (SCSI-based) device had front end ports for the host(s), back-end = ones for the devices, and side ones for the networking. Lots of = features, some you folks are only doing recently. Looked like devices = to hosts, hosts to devices. Anyway, the point of all of this is that when we sold it to customers, = the storage people looked at the network ports with confusion and dismay = (some hadn't even ordered the network lines and caused months of delay), = while the network people looked at the device ports as if they were full = of Tasmanian devils. Turned out, both network and storage expertise were very rare = commodities. This was largely why most iSCSI startups failed, they = either did a storage product or a networking product. We pilled this off = because I am stupid but stubborn and wrote the RTOS myself (Linux was in = its infancy and the other RTOS's sucked). Seemed a good idea at the = time. Have white papers online if anybody is interested. So, networking people may smell funny, but to them storage people come = from another galaxy. Working in this industry at all could be = considered a poor life choice but that's for another time. Sorry. You can go back to work now. Jim B -----Original Message----- From: Linux-nvme On Behalf Of = Christoph Hellwig Sent: Wednesday, March 12, 2025 8:09 AM To: Matthew Wilcox Cc: Hannes Reinecke ; Vlastimil Babka ; = Hannes Reinecke ; Boris Pismenny ; = John Fastabend ; Jakub Kicinski = ; Sagi Grimberg ; = linux-nvme@lists.infradead.org; linux-block@vger.kernel.org; = linux-mm@kvack.org; Harry Yoo ; = netdev@vger.kernel.org Subject: Re: Networking people smell funny and make poor life choices On Wed, Mar 05, 2025 at 06:11:24PM +0000, Matthew Wilcox wrote: > Networking needs to follow block's lead and STOP GETTING REFCOUNTS ON=20 > PAGES. The block layer never took references on pages. The direct I/O helpers = that just happened to set in block/ did hold references and abused some = field in the bio for it (and still do for the pinning), but the = reference was (and the pin now is) owned by the submitter. The block layer model has always been that the submitter needs to ensure = memory stays allocated until the I/O has completed. Which IMHO is the = only sane model for dealing with memory lifetimes vs I/O, and something = networking absolutely should follow.