Re: [PATCH] blk-mq: only run mapped hw queues in blk_mq_run_hw_queues()

Christian Borntraeger
2018-03-28T15:44:36Z

FWIW, these logs were from a different system (with less disks and cpus).
the related log is

[ 4.114191] dasd-eckd.2aa01a: 0.0.3f77: New DASD 3390/0C (CU 3990/01) with 30051 cylinders, 15 heads, 224 sectors
[ 4.114852] dasd-eckd.2aa01a: 0.0.3f74: New DASD 3390/0C (CU 3990/01) with 30051 cylinders, 15 heads, 224 sectors
[ 4.122361] dasd-eckd.412b53: 0.0.3f77: DASD with 4 KB/block, 21636720 KB total size, 48 KB/track, compatible disk layout
[ 4.122811] dasd-eckd.412b53: 0.0.3f74: DASD with 4 KB/block, 21636720 KB total size, 48 KB/track, compatible disk layout
[ 4.123568] dasdc:VOL1/ 0X3F77: dasdc1
[ 4.124092] dasdd:VOL1/ 0X3F74: dasdd1
[ 4.286220] WARNING: CPU: 1 PID: 1262 at block/blk-mq.c:1402 __blk_mq_delay_run_hw_queue+0xbe/0xd8
[ 4.286225] Modules linked in: autofs4
[ 4.286231] CPU: 1 PID: 1262 Comm: dasdconf.sh Not tainted 4.16.0-20180323.rc6.git0.792f5024dd01.300.fc27.s390x #1
[ 4.286232] Hardware name: IBM 2964 NC9 704 (LPAR)
[ 4.286236] Krnl PSW : 0000000053ccfc28 00000000c4b59c51 (__blk_mq_delay_run_hw_queue+0xbe/0xd8)
[ 4.286239] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
[ 4.286242] Krnl GPRS: 00000003da4eb000 0000000300000000 00000003dae67000 0000000000000001
[ 4.286243] 0000000000000000 00000003da4eb710 0000000300000000 000000010dbafd98
[ 4.286245] 000000010dbafd98 0000000000000001 0000000000000001 0000000000000000
[ 4.286248] 00000003dae67000 0000000000aaa750 000000010dbafc00 000000010dbafbc8
[ 4.286256] Krnl Code: 0000000000698e46: ebaff0a00004 lmg %r10,%r15,160(%r15)
0000000000698e4c: c0f4ffff7aca brcl 15,6883e0
#0000000000698e52: a7f40001 brc 15,698e54
>0000000000698e56: e340f0c00004 lg %r4,192(%r15)
0000000000698e5c: ebaff0a00004 lmg %r10,%r15,160(%r15)
0000000000698e62: 07f4 bcr 15,%r4
0000000000698e64: c0e5ffffff02 brasl %r14,698c68
0000000000698e6a: a7f4fff6 brc 15,698e56
[ 4.286301] Call Trace:
[ 4.286304] ([<000000010dbafc08>] 0x10dbafc08)
[ 4.286306] [<0000000000698f5a>] blk_mq_run_hw_queue+0x82/0x180
[ 4.286308] [<00000000006990c0>] blk_mq_run_hw_queues+0x68/0x88
[ 4.286310] [<00000000006982de>] __blk_mq_complete_request+0x11e/0x1d8
[ 4.286313] [<0000000000698424>] blk_mq_complete_request+0x8c/0xc8
[ 4.286319] [<000000000082c5d0>] dasd_block_tasklet+0x158/0x490
[ 4.286325] [<000000000014bc9a>] tasklet_hi_action+0x92/0x120
[ 4.286329] [<00000000009feeb0>] __do_softirq+0x120/0x348
[ 4.286331] [<000000000014b76a>] irq_exit+0xba/0xd0
[ 4.286335] [<000000000010bf92>] do_IRQ+0x8a/0xb8
[ 4.286337] [<00000000009fe180>] io_int_handler+0x130/0x298
[ 4.286338] Last Breaking-Event-Address:
[ 4.286340] [<0000000000698e52>] __blk_mq_delay_run_hw_queue+0xba/0xd8
[ 4.286342] ---[ end trace 0d746eb6f9348354 ]---

On 03/28/2018 05:36 PM, Christian Borntraeger wrote:
>
>
> On 03/28/2018 05:26 PM, Ming Lei wrote:
>> Hi Christian,
>>
>> On Wed, Mar 28, 2018 at 09:45:10AM +0200, Christian Borntraeger wrote:
>>> FWIW, this patch does not fix the issue for me:
>>>
>>> ostname=? addr=? terminal=? res=success'
>>> [ 21.454961] WARNING: CPU: 3 PID: 1882 at block/blk-mq.c:1410 __blk_mq_delay_run_hw_queue+0xbe/0xd8
>>> [ 21.454968] Modules linked in: scsi_dh_rdac scsi_dh_emc scsi_dh_alua dm_mirror dm_region_hash dm_log dm_multipath dm_mod autofs4
>>> [ 21.454984] CPU: 3 PID: 1882 Comm: dasdconf.sh Not tainted 4.16.0-rc7+ #26
>>> [ 21.454987] Hardware name: IBM 2964 NC9 704 (LPAR)
>>> [ 21.454990] Krnl PSW : 00000000c0131ea3 000000003ea2f7bf (__blk_mq_delay_run_hw_queue+0xbe/0xd8)
>>> [ 21.454996] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
>>> [ 21.455005] Krnl GPRS: 0000013abb69a000 0000013a00000000 0000013ac6c0dc00 0000000000000001
>>> [ 21.455008] 0000000000000000 0000013abb69a710 0000013a00000000 00000001b691fd98
>>> [ 21.455011] 00000001b691fd98 0000013ace4775c8 0000000000000001 0000000000000000
>>> [ 21.455014] 0000013ac6c0dc00 0000000000b47238 00000001b691fc08 00000001b691fbd0
>>> [ 21.455032] Krnl Code: 000000000069c596: ebaff0a00004 lmg %r10,%r15,160(%r15)
>>> 000000000069c59c: c0f4ffff7a5e brcl 15,68ba58
>>> #000000000069c5a2: a7f40001 brc 15,69c5a4
>>> >000000000069c5a6: e340f0c00004 lg %r4,192(%r15)
>>> 000000000069c5ac: ebaff0a00004 lmg %r10,%r15,160(%r15)
>>> 000000000069c5b2: 07f4 bcr 15,%r4
>>> 000000000069c5b4: c0e5fffffeea brasl %r14,69c388
>>> 000000000069c5ba: a7f4fff6 brc 15,69c5a6
>>> [ 21.455067] Call Trace:
>>> [ 21.455072] ([<00000001b691fd98>] 0x1b691fd98)
>>> [ 21.455079] [<000000000069c692>] blk_mq_run_hw_queue+0xba/0x100
>>> [ 21.455083] [<000000000069c740>] blk_mq_run_hw_queues+0x68/0x88
>>> [ 21.455089] [<000000000069b956>] __blk_mq_complete_request+0x11e/0x1d8
>>> [ 21.455091] [<000000000069ba9c>] blk_mq_complete_request+0x8c/0xc8
>>> [ 21.455103] [<00000000008aa250>] dasd_block_tasklet+0x158/0x490
>>> [ 21.455110] [<000000000014c742>] tasklet_hi_action+0x92/0x120
>>> [ 21.455118] [<0000000000a7cfc0>] __do_softirq+0x120/0x348
>>> [ 21.455122] [<000000000014c212>] irq_exit+0xba/0xd0
>>> [ 21.455130] [<000000000010bf92>] do_IRQ+0x8a/0xb8
>>> [ 21.455133] [<0000000000a7c298>] io_int_handler+0x130/0x298
>>> [ 21.455136] Last Breaking-Event-Address:
>>> [ 21.455138] [<000000000069c5a2>] __blk_mq_delay_run_hw_queue+0xba/0xd8
>>> [ 21.455140] ---[ end trace be43f99a5d1e553e ]---
>>> [ 21.510046] dasdconf.sh Warning: 0.0.241e is already online, not configuring
>>
>> Thinking about this issue further, I can't understand the root cause for
>> this issue.
>>
>> After commit 20e4d813931961fe ("blk-mq: simplify queue mapping & schedule with
>> each possisble CPU"), each hw queue should be mapped to at least one CPU, that
>> means this issue shouldn't happen. Maybe blk_mq_map_queues() works wrong?
>>
>> Could you dump 'lscpu' and provide blk-mq debugfs for your DASD via the
>> following command?
>
> # lscpu
> Architecture: s390x
> CPU op-mode(s): 32-bit, 64-bit
> Byte Order: Big Endian
> CPU(s): 16
> On-line CPU(s) list: 0-15
> Thread(s) per core: 2
> Core(s) per socket: 8
> Socket(s) per book: 3
> Book(s) per drawer: 2
> Drawer(s): 4
> NUMA node(s): 1
> Vendor ID: IBM/S390
> Machine type: 2964
> CPU dynamic MHz: 5000
> CPU static MHz: 5000
> BogoMIPS: 20325.00
> Hypervisor: PR/SM
> Hypervisor vendor: IBM
> Virtualization type: full
> Dispatching mode: horizontal
> L1d cache: 128K
> L1i cache: 96K
> L2d cache: 2048K
> L2i cache: 2048K
> L3 cache: 65536K
> L4 cache: 491520K
> NUMA node0 CPU(s): 0-15
> Flags: esan3 zarch stfle msa ldisp eimm dfp edat etf3eh highgprs te vx sie
>
> # lsdasd
> Bus-ID Status Name Device Type BlkSz Size Blocks
> ==============================================================================
> 0.0.3f75 active dasda 94:0 ECKD 4096 21129MB 5409180
> 0.0.3f76 active dasdb 94:4 ECKD 4096 21129MB 5409180
> 0.0.3f77 active dasdc 94:8 ECKD 4096 21129MB 5409180
> 0.0.3f74 active dasdd 94:12 ECKD 4096 21129MB 5409180
>
>>
>> (cd /sys/kernel/debug/block/$DASD && find . -type f -exec grep -aH . {} \;)
>
>
> see attachement:
>