Damien, > Handling checks of ZBC device capacity using the max_lba field of the > REPORT ZONES command reply for disks with rc_basis == 0 can be done > using the same report zones command reply used to check the "same" > field. > > Avoid executing a report zones command solely to check the disk capacity > by merging sd_zbc_check_capacity() into sd_zbc_check_zone_size() and > renaming that function to sd_zbc_check_zones(). This removes a costly > execution of a full report zones command and so reduces device scan > duration at boot time as well as the duration of disk revalidate calls. > > Furthermore, setting the partial report bit in the REPORT ZONES command > cdb can significantly reduce this command execution time as the device > does not have to count and report the total number of zones that could > be reported assuming a large enough reply buffer. A non-partial zone > report is necessary only for the first execution of report zones used to > check the same field value (to ensure that this value applies to all > zones of the disk). All other calls to sd_zbc_report_zones() can use a > partial report to reduce execution time. > > Using a 14 TB ZBC disk, these simple changes reduce device scan time at > boot from about 3.5s down to about 900ms. Disk revalidate times are also > reduced from about 450ms down to 230ms. Acked-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> -- Martin K. Petersen Oracle Linux Engineering
