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

Christian Borntraeger
2018-03-29T10:10:11Z

On 03/29/2018 11:40 AM, Ming Lei wrote:
> On Thu, Mar 29, 2018 at 11:09:08AM +0200, Christian Borntraeger wrote:
>>
>>
>> On 03/29/2018 09:23 AM, Christian Borntraeger wrote:
>>>
>>>
>>> On 03/29/2018 04:00 AM, Ming Lei wrote:
>>>> On Wed, Mar 28, 2018 at 05:36:53PM +0200, 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.
>>
>> FWIW, Limiting CONFIG_NR_CPUS to 64 seems to make the problem go away.
>
> I think the following patch is needed, and this way aligns to the mapping
> created via managed IRQ at least.
>
> diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
> index 9f8cffc8a701..638ab5c11b3c 100644
> --- a/block/blk-mq-cpumap.c
> +++ b/block/blk-mq-cpumap.c
> @@ -14,13 +14,12 @@
> #include "blk.h"
> #include "blk-mq.h"
>
> +/*
> + * Given there isn't CPU hotplug handler in blk-mq, map all possible CPUs to
> + * queues even it isn't present yet.
> + */
> static int cpu_to_queue_index(unsigned int nr_queues, const int cpu)
> {
> - /*
> - * Non present CPU will be mapped to queue index 0.
> - */
> - if (!cpu_present(cpu))
> - return 0;
> return cpu % nr_queues;
> }
>
> Thanks,
> Ming
>

With that I no longer see the WARN_ON but the other warning instead:

[ 31.903096] audit: type=1130 audit(1522318064.439:41): pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-tmpfiles-setup-dev comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
[ 31.903100] audit: type=1131 audit(1522318064.439:42): pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-tmpfiles-setup-dev comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
[ 31.985756] systemd-journald[379]: Received SIGTERM from PID 1 (systemd).
[ 32.000543] systemd: 18 output lines suppressed due to ratelimiting
[ 32.209496] EXT4-fs (dasdc1): re-mounted. Opts: (null)
[ 32.234808] systemd-journald[2490]: Received request to flush runtime journal from PID 1
[ 32.359832] tun: Universal TUN/TAP device driver, 1.6
[ 32.470841] run queue from wrong CPU 18, hctx active
[ 32.470845] CPU: 18 PID: 2131 Comm: kworker/18:1H Not tainted 4.16.0-rc7+ #31
[ 32.470847] Hardware name: IBM 2964 NC9 704 (LPAR)
[ 32.470856] Workqueue: kblockd blk_mq_run_work_fn
[ 32.470857] Call Trace:
[ 32.470862] ([<0000000000113b86>] show_stack+0x56/0x80)
[ 32.470867] [<0000000000a5cd02>] dump_stack+0x82/0xb0
[ 32.470869] [<000000000069c40a>] __blk_mq_run_hw_queue+0x12a/0x130
[ 32.470873] [<0000000000163906>] process_one_work+0x1be/0x420
[ 32.470875] [<0000000000163bc0>] worker_thread+0x58/0x458
[ 32.470877] [<000000000016a9d0>] kthread+0x148/0x160
[ 32.470880] [<0000000000a7bea2>] kernel_thread_starter+0x6/0xc
[ 32.470882] [<0000000000a7be9c>] kernel_thread_starter+0x0/0xc
[ 32.470889] run queue from wrong CPU 18, hctx active
[ 32.470891] CPU: 18 PID: 2131 Comm: kworker/18:1H Not tainted 4.16.0-rc7+ #31
[ 32.470892] Hardware name: IBM 2964 NC9 704 (LPAR)
[ 32.470894] Workqueue: kblockd blk_mq_run_work_fn
[ 32.470895] Call Trace:
[ 32.470897] ([<0000000000113b86>] show_stack+0x56/0x80)
[ 32.470898] [<0000000000a5cd02>] dump_stack+0x82/0xb0
[ 32.470900] [<000000000069c40a>] __blk_mq_run_hw_queue+0x12a/0x130
[ 32.470902] [<0000000000163906>] process_one_work+0x1be/0x420
[ 32.470903] [<0000000000163bc0>] worker_thread+0x58/0x458
[ 32.470905] [<000000000016a9d0>] kthread+0x148/0x160
[ 32.470906] [<0000000000a7bea2>] kernel_thread_starter+0x6/0xc
[ 32.470908] [<0000000000a7be9c>] kernel_thread_starter+0x0/0xc
[ 32.470910] run queue from wrong CPU 18, hctx active
[ 32.470911] CPU: 18 PID: 2131 Comm: kworker/18:1H Not tainted 4.16.0-rc7+ #31
[ 32.470913] Hardware name: IBM 2964 NC9 704 (LPAR)
[ 32.470914] Workqueue: kblockd blk_mq_run_work_fn
[ 32.470916] Call Trace:
[ 32.470918] ([<0000000000113b86>] show_stack+0x56/0x80)
[ 32.470919] [<0000000000a5cd02>] dump_stack+0x82/0xb0
[ 32.470921] [<000000000069c40a>] __blk_mq_run_hw_queue+0x12a/0x130
[ 32.470922] [<0000000000163906>] process_one_work+0x1be/0x420
[ 32.470924] [<0000000000163bc0>] worker_thread+0x58/0x458
[ 32.470925] [<000000000016a9d0>] kthread+0x148/0x160
[ 32.470927] [<0000000000a7bea2>] kernel_thread_starter+0x6/0xc
[ 32.470929] [<0000000000a7be9c>] kernel_thread_starter+0x0/0xc
[ 32.470930] run queue from wrong CPU 18, hctx active
[ 32.470932] CPU: 18 PID: 2131 Comm: kworker/18:1H Not tainted 4.16.0-rc7+ #31
[ 32.470933] Hardware name: IBM 2964 NC9 704 (LPAR)
[ 32.470935] Workqueue: kblockd blk_mq_run_work_fn
[ 32.470936] Call Trace:
[ 32.470938] ([<0000000000113b86>] show_stack+0x56/0x80)
[ 32.470939] [<0000000000a5cd02>] dump_stack+0x82/0xb0
[ 32.470941] [<000000000069c40a>] __blk_mq_run_hw_queue+0x12a/0x130
[ 32.470943] [<0000000000163906>] process_one_work+0x1be/0x420
[ 32.470944] [<0000000000163bc0>] worker_thread+0x58/0x458
[ 32.470946] [<000000000016a9d0>] kthread+0x148/0x160
[ 32.470947] [<0000000000a7bea2>] kernel_thread_starter+0x6/0xc
[ 32.470949] [<0000000000a7be9c>] kernel_thread_starter+0x0/0xc
[ 32.470950] run queue from wrong CPU 18, hctx active
[ 32.470952] CPU: 18 PID: 2131 Comm: kworker/18:1H Not tainted 4.16.0-rc7+ #31
[ 32.470953] Hardware name: IBM 2964 NC9 704 (LPAR)
[ 32.470955] Workqueue: kblockd blk_mq_run_work_fn
[ 32.470956] Call Trace:
[ 32.470958] ([<0000000000113b86>] show_stack+0x56/0x80)
[ 32.470959] [<0000000000a5cd02>] dump_stack+0x82/0xb0
[ 32.470961] [<000000000069c40a>] __blk_mq_run_hw_queue+0x12a/0x130
[ 32.470963] [<0000000000163906>] process_one_work+0x1be/0x420
[ 32.470964] [<0000000000163bc0>] worker_thread+0x58/0x458
[ 32.470966] [<000000000016a9d0>] kthread+0x148/0x160
[ 32.470967] [<0000000000a7bea2>] kernel_thread_starter+0x6/0xc
[ 32.470969] [<0000000000a7be9c>] kernel_thread_starter+0x0/0xc
[ 32.470971] run queue from wrong CPU 18, hctx active
[ 32.470972] CPU: 18 PID: 2131 Comm: kworker/18:1H Not tainted 4.16.0-rc7+ #31
[ 32.470973] Hardware name: IBM 2964 NC9 704 (LPAR)
[ 32.470975] Workqueue: kblockd blk_mq_run_work_fn
[ 32.470976] Call Trace:
[ 32.470978] ([<0000000000113b86>] show_stack+0x56/0x80)
[ 32.470979] [<0000000000a5cd02>] dump_stack+0x82/0xb0
[ 32.470981] [<000000000069c40a>] __blk_mq_run_hw_queue+0x12a/0x130
[ 32.470983] [<0000000000163906>] process_one_work+0x1be/0x420
[ 32.470985] [<0000000000163bc0>] worker_thread+0x58/0x458
[ 32.470986] [<000000000016a9d0>] kthread+0x148/0x160
[ 32.470988] [<0000000000a7bea2>] kernel_thread_starter+0x6/0xc
[ 32.470989] [<0000000000a7be9c>] kernel_thread_starter+0x0/0xc
[ 32.470991] run queue from wrong CPU 18, hctx active
[ 32.470992] CPU: 18 PID: 2131 Comm: kworker/18:1H Not tainted 4.16.0-rc7+ #31
[ 32.470993] Hardware name: IBM 2964 NC9 704 (LPAR)
[ 32.470995] Workqueue: kblockd blk_mq_run_work_fn