On Fri, Jul 08, 2022 at 04:54:47PM +0200, Vlastimil Babka wrote: > On 7/8/22 16:44, Mel Gorman wrote: > > pcpu_spin_unlock and pcpu_spin_unlock_irqrestore both unlock > > pcp->lock and then enable preemption. This lacks symmetry against > > both the pcpu_spin helpers and differs from how local_unlock_* is > > implemented. While this is harmless, it's unnecessary and it's generally > > better to unwind locks and preemption state in the reverse order as > > they were acquired. > > Hm I'm confused, it seems it's done in reverse order (which I agree with) > before this -fix-fix, but not after it? > > before, pcpu_spin_lock() (and variants) do pcpu_task_pin() and then > spin_lock() (or variant), and pcpu_spin_unlock() does spin_unlock() and then > pcpu_task_unpin(). That seems symmetrical, i.e. reverse order to me? And > seems to match what local_lock family does too. > You're not confused, I am. The patch and the changelog are outright brain damage from excessive context switching and a sign that it's time for the weekend to start. Sorry for this absolute misfortune. -- Mel Gorman SUSE Labs
