----- On Nov 15, 2016, at 2:51 AM, Peter Zijlstra pet...@infradead.org wrote:
> On Mon, Nov 14, 2016 at 10:36:36AM -0800, Paul E. McKenney wrote: >> SRCU uses two per-cpu counters: a nesting counter to count the number of >> active critical sections, and a sequence counter to ensure that the nesting >> counters don't change while they are being added together in >> srcu_readers_active_idx_check(). >> >> This patch instead uses per-cpu lock and unlock counters. Because the both >> counters only increase and srcu_readers_active_idx_check() reads the unlock >> counter before the lock counter, this achieves the same end without having >> to increment two different counters in srcu_read_lock(). This also saves a >> smp_mb() in srcu_readers_active_idx_check(). > > A very small improvement... I feel SRCU has much bigger issues :/ Do you have specific issues in mind ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
