explicit on-stack per-task plugging

• 末节的 Discussion 很精彩，大神 Neil Brown 答疑解惑
• A block layer introduction part 1: the bio layer, Neil Brown, October 25, 2017, lwn.net
• Explicit block device plugging, Jens Axboe, April 13, 2011, lwn.net
• No more global unplugging, corbet, March 10, 2004, lwn.net

plugging 进化

• global plugging/unplugging : performance …