vchiq: Performance regression since 5.18-rc1

[Sebastian Andrzej Siewior]

On 2022-05-22 01:22:00 [+0200], Stefan Wahren wrote:
> Hi,
Hi,

> while testing the staging/vc04_services/interface/vchiq_arm driver with my
> Raspberry Pi 3 B+ (multi_v7_defconfig) i noticed a huge performance
> regression since [ff042f4a9b050895a42cae893cc01fa2ca81b95c] mm:
> lru_cache_disable: replace work queue synchronization with synchronize_rcu
> 
> Usually i run "vchiq_test -f 1" to see the driver is still working [1].

What about
	https://lore.kernel.org/all/YmrWK%2FKoU1zrAxPI@fuller.cnet/

Sebastian