[PATCH V5 0/4] blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING

[Sagi Grimberg]

>> Hi Jens,
>>
>> The 1st patch add .mq_quiesce_mutex for serializing quiesce/unquiesce,
>> and prepares for replacing srcu with percpu_ref.
>>
>> The 2nd patch replaces srcu with percpu_ref.
>>
>> The 3rd patch adds tagset quiesce interface.
>>
>> The 4th patch applies tagset quiesce interface for NVMe subsystem.
> 
> Tested some reset storms and target restarts during traffic with
> nvme-tcp.
> 
> Seems that no apparent breakage.
> 
> So:
> 
> Tested-by: Sagi Grimberg <sagi at grimberg.me>

Probably unrelated to this patches, but I do see new
kmemleak complaints in the form of:
--
unreferenced object 0xffff9440dbf3c240 (size 64):
   comm "systemd", pid 1, jiffies 4306444056 (age 25034.440s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 b0 fe 13 99 ff ff ff ff  ................
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   backtrace:
     [<00000000f1d0b20e>] percpu_ref_init+0x5f/0xf0
     [<000000009598103f>] cgroup_mkdir+0xe9/0x440
     [<0000000001b93c19>] kernfs_iop_mkdir+0x57/0x80
     [<000000001ed0f985>] vfs_mkdir+0x10e/0x1d0
     [<00000000cac65f7e>] do_mkdirat+0xec/0x120
     [<00000000956db630>] do_syscall_64+0x33/0x80
     [<000000001c2b0e1a>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
--