Hello,

On Thu, Jul 18, 2024 at 01:21:32AM +0000, Boy Wu (吳勃誼) wrote:
...

I think this will work, but as I mentioned before, this issue is only
on 32 bit SMP systems. Replacing u64 sync with spinlock will increase
overhead on 64 bit systems, because u64 sync does nothing on 64 bit
systems. However, if it is acceptable, we can proceed with this
solution.

We can encapsulate the spinlock in some helpers and make them conditional on
32bit. However, the u64_sync -> spinlock conversions in the suggested patch
are all on cold paths, so I doubt it'd be all that noticeable especially
given that the hottest path of them all is already grabbing blkg_stat_lock,
but either way is fine by me.

Thanks.

-- 
tejun