Re: Hard and soft lockups with FIO and LTP runs on a large system

[Hillf Danton]

On Wed, 17 Jul 2024 16:20:04 +0530 Bharata B Rao <bharata@xxxxxxx>
> On 17-Jul-24 3:07 PM, Vlastimil Babka wrote:
> > 
> > It seems weird to me to see anything that would require ZONE_DMA allocation
> > on a modern system. Do you know where it comes from?
> 
> We measured the lruvec spinlock start, end and hold
> time(htime) using sched_clock(), along with a BUG() if the hold time was
> more than 10s. The below case shows that lruvec spin lock was held for ~25s.
>
What is more unusual could be observed perhaps with your hardware config but
with 386MiB RAM assigned to each node, the so called tight memory but not
extremely tight.