Eric Dumazet <eduma...@google.com> wrote:
> > + /* ... so wait for even xt_recseq on all cpus */
> > + for_each_possible_cpu(cpu) {
> > + seqcount_t *s = &per_cpu(xt_recseq, cpu);
> > +
> > + while (raw_read_seqcount(s) & 1)
> > + cpu_relax();
> > +
> > + cond_resched();
> > + }
>
> It seems that we could also check :
>
> 1) If low order bit of sequence is 0
>
> Or
>
> 2) the value has changed
> for_each_possible_cpu(cpu) {
> seqcount_t *s = &per_cpu(xt_recseq, cpu);
> u32 seq = raw_read_seqcount(s) ;
>
> if (seq & 1) {
> do {
> cpu_relax();
> } while (seq == raw_read_seqcount(s));
>
Actually I first used
for_each_possible_cpu(cpu) {
seqcount_t *s = &per_cpu(xt_recseq, cpu);
(void)__read_seqcount_begin(s);
}
but it looked confusing (not paired with a _retry function).
I'll respin with a loop like your suggestion above. Thanks!
