On Mon, Aug 31, 2020 at 03:22:15PM -0400, Mikulas Patocka wrote: > Hi > > I report this RCU stall when working with one 512GiB file the XFS > filesystem on persistent memory. Except for the warning, there was no > observed misbehavior. > > Perhaps, it is missing cond_resched() somewhere. Yikes, you can send a 2T request to a pmem device?? /sys/block/pmem0/queue/max_hw_sectors_kb : 2147483647 My puny laptop can only push 29GB/s, which I guess means we could stall on an IO request for 70 seconds... --D > Mikulas > > > [187395.754249] XFS (pmem3): Mounting V5 Filesystem > [187395.766583] XFS (pmem3): Ending clean mount > [187395.771434] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) > [188226.398260] rcu: INFO: rcu_sched self-detected stall on CPU > [188226.404609] rcu: 11-....: (37223 ticks this GP) idle=5a2/1/0x4000000000000000 softirq=259495/259495 fqs=13202 > [188226.416134] (t=60017 jiffies g=8444929 q=28811) > [188226.421405] NMI backtrace for cpu 11 > [188226.425492] CPU: 11 PID: 36509 Comm: kworker/11:0 Tainted: G S O 5.9.0-rc2 #3 > [188226.434886] Hardware name: Intel Corporation PURLEY/PURLEY, BIOS PLYXCRB1.86B.0576.D20.1902150028 02/15/2019 > [188226.446099] Workqueue: xfs-conv/pmem3 xfs_end_io [xfs] > [188226.451966] Call Trace: > [188226.454818] <IRQ> > [188226.457184] dump_stack+0x57/0x70 > [188226.460980] nmi_cpu_backtrace.cold.8+0x13/0x4f > [188226.466135] ? lapic_can_unplug_cpu.cold.36+0x37/0x37 > [188226.471870] nmi_trigger_cpumask_backtrace+0xc8/0xca > [188226.477512] rcu_dump_cpu_stacks+0xae/0xdc > [188226.482182] rcu_sched_clock_irq.cold.94+0x10a/0x366 > [188226.487822] ? trigger_load_balance+0x3c/0x240 > [188226.492881] ? tick_sched_do_timer+0x70/0x70 > [188226.497742] ? tick_sched_do_timer+0x70/0x70 > [188226.502620] update_process_times+0x24/0x60 > [188226.507401] tick_sched_handle.isra.26+0x35/0x40 > [188226.512651] tick_sched_timer+0x65/0x80 > [188226.517083] __hrtimer_run_queues+0x100/0x280 > [188226.522042] hrtimer_interrupt+0x100/0x220 > [188226.526710] ? rcu_iw_handler+0x19/0x40 > [188226.531089] __sysvec_apic_timer_interrupt+0x5d/0xf0 > [188226.536720] asm_call_on_stack+0xf/0x20 > [188226.541098] </IRQ> > [188226.543540] sysvec_apic_timer_interrupt+0x73/0x80 > [188226.548984] asm_sysvec_apic_timer_interrupt+0x12/0x20 > [188226.554844] RIP: 0010:_raw_spin_unlock_irqrestore+0xe/0x10 > [188226.561062] Code: 00 8b 07 85 c0 75 0b ba 01 00 00 00 f0 0f b1 17 74 03 31 c0 c3 b8 01 00 00 00 c3 90 0f 1f 44 00 00 c6 07 00 0f 1f 40 00 56 9d <c3> 90 0f 1f 44 00 00 8b 07 a9 ff 01 00 00 75 1e ba 00 02 00 00 f0 > [188226.582119] RSP: 0000:ffffb013ce1dbd28 EFLAGS: 00000206 > [188226.588049] RAX: 0000000000000000 RBX: ffffefef65cd7f40 RCX: 0000000000000180 > [188226.596109] RDX: ffff8956c7d1fa38 RSI: 0000000000000206 RDI: ffff896c5dcd4db0 > [188226.604171] RBP: 0000000000000001 R08: ffffb013ce1dbcf0 R09: 0000000000000206 > [188226.612232] R10: 00000000000313d5 R11: 0000000000000001 R12: ffff896a0bbe4000 > [188226.620293] R13: ffff896d59ae4800 R14: ffff896c5dcd4da8 R15: ffff8c9234c54860 > [188226.628399] test_clear_page_writeback+0xd7/0x300 > [188226.633750] end_page_writeback+0x43/0x60 > [188226.638326] iomap_finish_ioend+0x17f/0x200 > [188226.643103] ? xfs_iomap_write_unwritten+0x18a/0x2c0 [xfs] > [188226.649322] iomap_finish_ioends+0x43/0xa0 > [188226.653999] xfs_end_ioend+0x6b/0x100 [xfs] > [188226.658825] ? xfs_setfilesize_ioend+0x60/0x60 [xfs] > [188226.664482] xfs_end_io+0xad/0xe0 [xfs] > [188226.668860] process_one_work+0x206/0x3d0 > [188226.673431] ? process_one_work+0x3d0/0x3d0 > [188226.678197] worker_thread+0x2d/0x3d0 > [188226.682380] ? process_one_work+0x3d0/0x3d0 > [188226.687146] kthread+0x116/0x130 > [188226.690844] ? kthread_park+0x80/0x80 > [188226.695029] ret_from_fork+0x1f/0x30 > [188510.467258] XFS (pmem3): Unmounting Filesystem > [188514.316739] XFS (pmem3): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > [188514.325229] XFS (pmem3): Mounting V5 Filesystem > [188514.338115] XFS (pmem3): Ending clean mount > [188514.342969] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) > [188547.273256] XFS (pmem3): Unmounting Filesystem > [188551.349615] XFS (pmem3): Mounting V5 Filesystem > [188551.362393] XFS (pmem3): Ending clean mount > [188551.367259] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) > [188623.505834] XFS (pmem3): Unmounting Filesystem > [188627.935790] XFS (pmem3): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > [188627.944297] XFS (pmem3): Mounting V5 Filesystem > [188627.957588] XFS (pmem3): Ending clean mount > [188627.962455] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) > [188727.574325] XFS (pmem3): Unmounting Filesystem > [188730.257546] XFS (pmem3): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > [188730.266029] XFS (pmem3): Mounting V5 Filesystem > [188730.277924] XFS (pmem3): Ending clean mount > [188730.282780] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) > [188731.157151] XFS (pmem3): Unmounting Filesystem > [188732.031577] XFS (pmem3): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > [188732.040047] XFS (pmem3): Mounting V5 Filesystem > [188732.049865] XFS (pmem3): Ending clean mount > [188732.054673] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) > [188752.654883] XFS (pmem3): Unmounting Filesystem > [188753.536132] XFS (pmem3): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > [188753.544610] XFS (pmem3): Mounting V5 Filesystem > [188753.556100] XFS (pmem3): Ending clean mount > [188753.560954] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) > [189643.193075] XFS (pmem3): Unmounting Filesystem > [189646.828861] XFS (pmem3): Mounting V5 Filesystem > [189646.841023] XFS (pmem3): Ending clean mount > [189646.845865] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) > [189703.029858] XFS (pmem3): Unmounting Filesystem > [189705.756862] XFS (pmem3): DAX enabled. Warning: EXPERIMENTAL, use at your own risk > [189705.765342] XFS (pmem3): Mounting V5 Filesystem > [189705.777044] XFS (pmem3): Ending clean mount > [189705.781896] xfs filesystem being mounted at /mnt/xfs supports timestamps until 2038 (0x7fffffff) >
