On 7/17/23 23:43, Adrian Hunter wrote:
On 17/07/23 22:36, Bart Van Assche wrote:
Interest among UFS users in HPB has reduced significantly.
Can you say more about why, or give some background?
Hi Adrian,
I haven't seen any recent changes in the HPB implementation - neither
upstream nor in the Android kernel. That makes me wonder whether there
are any HPB users left at all. If there are any HPB users left, it's
time for them to speak up. Additionally, the work in JEDEC on a
successor for HPB nears completion (Zoned storage for UFS or ZUFS).
My motivation for removing the HPB code is that I want to make
blk_mq_run_hw_queue() faster if BLK_MQ_F_BLOCKING is set. The patch
series I posted
(https://lore.kernel.org/linux-block/20230717205216.2024545-1-bvanassche@xxxxxxx/)
may cause blk_execute_rq_nowait() to sleep. The HPB code is the only
code I am aware of that calls blk_execute_rq_nowait() from a context
where it is not allowed to sleep. If the HPB code is removed, I don't
have to modify it to make it compatible with the blk_execute_rq_nowait()
changes.
Bart.
