On 9/2/20 6:26 AM, Ming Lei wrote:

Hi,

The 1st patch removes memory footprint of percpu_ref in fast path
from 7 words to 2 words, since it is often used in fast path and
embedded in user struct.

The 2nd patch moves .q_usage_counter to 1st cacheline of
'request_queue'.

Simple test on null_blk shows ~2% IOPS boost on one 16cores(two threads
per core) machine, dual socket/numa.

V2:
	- pass 'gfp' to kzalloc() for fixing block/027 failure reported by
	kernel test robot
	- protect percpu_ref_is_zero() with destroying percpu-refcount by
	spin lock  

Ming Lei (2):
  percpu_ref: reduce memory footprint of percpu_ref in fast path
  block: move 'q_usage_counter' into front of 'request_queue'

Applied, thanks.

-- 
Jens Axboe