Wang, > We have a sata ssd with following parameters, > > max_ws_blocks = 0 > max_unmap_blocks = 262143 > lbprz = 1 > lbpu = 1 > unmap_limit_for_ws = 0 The device is explicitly asking for us to use UNMAP so the older kernel choosing WRITE SAME(16) was not correct. I have been working on an update to the discard/zeroing heuristics that I'll post when 5.15 opens next week. But based on what's reported it by your device we would still choose UNMAP for discards. LBPRZ only affects which command we use for zeroing. -- Martin K. Petersen Oracle Linux Engineering
