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Douglas Gilbert
ed9f3e2513
scsi: scsi_debug: Implement PRE-FETCH commands
Many disks implement the SCSI PRE-FETCH commands. One use case might be a disk-to-disk compare, say between disks A and B. Then this sequence of commands might be used: PRE-FETCH(from B, IMMED), READ(from A), VERIFY (BYTCHK=1 on B with data returned from READ). The PRE-FETCH (which returns quickly due to the IMMED) fetches the data from the media into B's cache which should speed the trailing VERIFY command. The next chunk of the compare might be done in parallel, with A and B reversed. The implementation tries to bring the specified range in main memory into the cache(s) associated with this machine's CPU(s) using the prefetch_range() function. Link: https://lore.kernel.org/r/20200421151424.32668-7-dgilbert@interlog.com Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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