Re: [PATCH net-next] qlcnic: Optimize performance by replacing rw_lock with spinlock

[Simon Horman]

On Fri, Mar 07, 2025 at 12:31:24AM +0800, Yu-Chun Lin wrote:
> The 'crb_lock', an rwlock, is only used by writers, making it functionally
> equivalent to a spinlock.
> 
> According to Documentation/locking/spinlocks.rst:
> 
> "Reader-writer locks require more atomic memory operations than simple
> spinlocks. Unless the reader critical section is long, you are better
> off just using spinlocks."
> 
> Since read_lock() is never called, switching to a spinlock reduces
> overhead and improves efficiency.
> 
> Signed-off-by: Yu-Chun Lin <eleanor15x@xxxxxxxxx>

Hi Yu-Chun Lin,

Thanks for your patch.

My main question is if you have hardware to test this?
And if so, was a benefit observed?

If not, my feeling is that although your change looks
correct, we'd be better off taking the lower risk option
of leaving things be.