On Fri, Oct 04, 2019 at 01:11:06PM +0300, Konstantin Khlebnikov wrote: > This is very slow operation. There is no reason to do it again if somebody > else already drained all per-cpu vectors after we waited for lock. > + seq = raw_read_seqcount_latch(&seqcount); > + > mutex_lock(&lock); > + > + /* Piggyback on drain done by somebody else. */ > + if (__read_seqcount_retry(&seqcount, seq)) > + goto done; > + > + raw_write_seqcount_latch(&seqcount); > + Do we really need the seqcount to do this? Wouldn't a mutex_trylock() have the same effect?
