On Wed, Feb 17, 2021 at 09:16:12PM +0000, Matthew Wilcox wrote: > On Wed, Feb 17, 2021 at 12:46:19PM -0800, Minchan Kim wrote: > > > I suspect you do not want to add atomic_read inside hot paths, right? Is > > > this really something that we have to microoptimize for? atomic_read is > > > a simple READ_ONCE on many archs. > > > > It's also spin_lock_irq_save in some arch. If the new synchonization is > > heavily compilcated, atomic would be better for simple start but I thought > > this locking scheme is too simple so no need to add atomic operation in > > readside. > > What arch uses a spinlock for atomic_read()? I just had a quick grep and > didn't see any. Ah, my bad. I was confused with update side. Okay, let's use atomic op to make it simple. Thanks for the review, Mattew and Michal.
