On Wed, Feb 17, 2016 at 12:00:40PM +0100, Peter Zijlstra wrote: > On Wed, Feb 17, 2016 at 08:53:18PM +1100, Dave Chinner wrote: > > > +/** > > > + * for_all_percpu_list_entries - iterate over all the per-cpu list with > > > locking
But the locking is 'pointless'. You only lock one per-cpu sublist at a time, therefore the list can be modified concurrently anyhow. So why not use RCU for the list iteration and avoid potentially large lock hold times? > > > + * @pos: the type * to use as a loop cursor for the current . > > > + * @next: an internal type * variable pointing to the next entry > > > + * @pchead: an internal struct list * of percpu list head > > > + * @pclock: an internal variable for the current per-cpu spinlock > > > + * @head: the head of the per-cpu list > > > + * @member: the name of the per-cpu list within the struct > > > + */
