Re: [PATCH v8 05/10] block: Add core atomic write support
John Garry <[email protected]>
| Newsgroups | gmane.linux.kernel.aio.general,gmane.linux.block,gmane.linux.kernel,gmane.linux.file-systems,gmane.linux.scsi,gmane.comp.file-systems.btrfs,gmane.linux.kernel.io-uring |
|---|---|
| Organization | Oracle Corporation |
| Message-ID | <[email protected]> |
On 18/06/2024 18:25, Keith Busch wrote: > On Tue, Jun 18, 2024 at 08:46:31AM +0100, John Garry wrote: >> About NVMe, the spec says that NABSN and NOIOB may not be related to one >> another (command set spec 1.0d 5.8.2.1), but I am wondering if people really >> build HW which would have different NABSN/NABSPF and NOIOB. I don't know. > The history of NOIOB is from an nvme drive that had two back-end > controllers with their own isolated storage, and then striped together > on the front end for the host to see. A command crossing the stripe > boundary takes a slow path to split it for each backend controller's > portion and merge the results. Subsequent implementations may have > different reasons for advertising this boundary, but that was the > original. In this case, I would expect NOIOB >= atomic write boundary. Would it be sane to have a NOIOB < atomic write boundary in some other config? I can support these possibilities, but the code will just get more complex. > > Anyway, there was an idea that the stripe size could be user > configurable, though that never shipped as far as I know. If it had, > then the optimal NOIOB could be made larger, but the atomic write size > doesn't change. Thanks, John -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to [email protected]. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: <a href=mailto:"[email protected]">[email protected]</a>