Hi Chenxiang, On Wed, Nov 29, 2017 at 10:57:06AM +0800, chenxiang (M) wrote: > 在 2017/11/27 20:41, Ming Lei 写道: > > On Thu, Nov 23, 2017 at 12:47:58PM +0800, Ming Lei wrote: > > > Hi Jens, > > > > > > The 1st patch runs queue in blk_freeze_queue_start() for fixing one > > > regression by 055f6e18e08f("block: Make q_usage_counter also track legacy > > > requests"). > > > > > > The 2nd patch drians blkcg part of request_queue for both blk-mq and > > > legacy, which can be a fix on blk-mq's queue cleanup. > > > > > > V2: > > > - follow Bart's suggestion to use run queue instead of drain queue > > > - drians blkcg part of request_queue for blk-mq > > > > > Hi Jens, > > > > Without this patchset, IO hang can be triggered in Mauricio's disk > > pull test, and this IO hang won't happen any more after this patchset > > is applied. > > > > So could you make it in V4.15 if you are fine with the two patches? > > Hi Lei Ming, > > I applied this v2 patchset to kernel 4.15-rc1, running fio on a SATA disk, > then disable the disk with sysfs interface I guess it is a SAS disk? > (echo 0 > /sys/class/sas_phy/phy-1:0:1/enable), and find system is hung. But > with v1 patch, it doesn't > has this issue. Please have a check. Thanks for your test! Then looks even though V2 can fix Mauricio's issue, it still can't fix yours, which is a regression caused by 055f6e18e08f("block: Make q_usage_counter also track legacy requests"). Given V1 can fix both your issue and Mauricio's, I will post V3 which falls back to original V1. Thanks, Ming