Hi Kashyap,
John - I have not seen such issue on megaraid_sas driver.
I could try to test megaraid SAS also, but the system with that card has
only 1x SATA disk, so pointless really.
Is this something
to do with CPU lock up ?
Seems to be.
JFYI, Enabling configs RCU_EXPERT, DEBUG_ATOMIC_SLEEP, and
DEBUG_SPINLOCK gives:
job1: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
4096B-4096B, ioengine=libaio, iodepth=128
job1: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
4096B-4096B, ioengine=libaio, iodepth=128
job1: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
4096B-4096B, ioengine=libaio, iodepth=128
fio-3.1
Starting 6 processes
[ 196.342724] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:ta
01h:12m:22s]
[ 196.348816] rcu: Tasks blocked on level-1 rcu_node (CPUs 32-47):
[ 196.354913] rcu: All QSes seen, last rcu_preempt kthread activity 1
(4294941135-4294941134), jiffies_till_next_fqs=1, root ->qsmask 0x4
[ 196.367089] BUG: sleeping function called from invalid context at
include/linux/uaccess.h:174
[ 196.375605] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid:
1893, name: fio
[ 196.383502] BUG: scheduling while atomic: fio/1893/0x00000004
[ 196.389312] BUG: spinlock recursion on CPU#11, fio/1893
[ 196.394527] lock: rcu_state+0x280/0x2d00, .magic: dead4ead, .owner:
fio/1893, .owner_cpu: 11
[ 196.403046] CPU: 11 PID: 1893 Comm: fio Tainted: G W
5.12.0-rc7-00001-g3ae18ff9e445 #219
[ 196.412426] Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon
D05 IT21 Nemo 2.0 RC0 04/18/2018
[ 196.421544] Call trace:
[ 196.423977] dump_backtrace+0x0/0x1b0
[ 196.427629] show_stack+0x18/0x68
[ 196.430932] dump_stack+0xd8/0x134
[ 196.434322] spin_dump+0x84/0x94
[ 196.437539] do_raw_spin_lock+0x108/0x120
[ 196.441539] _raw_spin_lock+0x20/0x30
[ 196.445191] rcu_note_context_switch+0xbc/0x348
[ 196.449710] __schedule+0xc8/0x6e8
[ 196.453100] preempt_schedule_notrace+0x50/0x70
[ 196.457618] __arm64_sys_io_submit+0x188/0x240
[ 196.462051] el0_svc_common.constprop.2+0x8c/0x128
[ 196.466829] do_el0_svc+0x24/0x90
[ 196.470133] el0_svc+0x24/0x38
[ 196.473175] el0_sync_handler+0x90/0xb8
[ 196.476999] el0_sync+0x154/0x180
^Cbs: 6 (f=6): [r(6)][4.2%][r=0KiB/s,w=0KiB/s][r=0,w=0 IOPS][eta
01h:11m:54s]
fio: terminating on signal 2
Can you try your test with "rq_affinity=2" ?
I cannot see the issue with this setting.
megaraid_sas driver detect CPU
lockup (flood of completion on single CPU) and it use irq_poll interface to
avoid such loop.
Can you turn it off? I guess that this is what happens to me, but the
system should not hang.
Since you mentioned you noticed issue with hisi_sas v2 without hostwide tag
I can think of similar stuffs in this case.
How cpus to irq affinity settled in your case. ? Is it 1-1 mapping ?
We have a 4-1 CPU-HW queue mapping.
Disabling CONFIG_PREEMPT makes the issue go away for me also, so it
would be useful to try enabling it to recreate (if disabled), like:
more .config| grep PREEMPT
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
CONFIG_PREEMPT_COUNT=y
CONFIG_PREEMPTION=y
CONFIG_PREEMPT_RCU=y
CONFIG_PREEMPT_NOTIFIERS=y
# CONFIG_DEBUG_PREEMPT is not set
Thanks,
John
Kashyap
scsi debug or null_blk don't seem to load the system heavily enough to
recreate.
I have seen it on 5.11 also. I see it on hisi_sas v2 and v3 hw drivers,
And I don't
think it's related to hostwide tags, as for hisi_sas v2 hw driver, I unset
that flag
and can still see it.
Thanks,
John
[0]
https://lore.kernel.org/linux-scsi/89ebc37c-21d6-c57e-4267-
cac49a3e5953@xxxxxxxxxx/T/#t
