Hi,
在 2022/09/02 17:42, Guoqing Jiang 写道:
Hi,
On 8/29/22 9:15 PM, Yu Kuai wrote:
+static bool wait_barrier_nolock(struct r10conf *conf)
+{
+ unsigned int seq = raw_read_seqcount(&conf->resync_lock.seqcount);
+
+ if (seq & 1)
+ return false;
+
+ if (READ_ONCE(conf->barrier))
+ return false;
+
+ atomic_inc(&conf->nr_pending);
+ if (!read_seqcount_retry(&conf->resync_lock.seqcount, seq))
I think 'seq' is usually get from read_seqcount_begin.
read_seqcount_begin will loop untill "req & 1" failed, I'm afraid this
will cause high cpu usage in come cases.
What I try to do here is just try once, and fall back to hold lock and
wait if failed.
What do you think?
Thanks,
Kuai
+ return true;
+
+ atomic_dec(&conf->nr_pending);
+ return false;
+
Thanks,
Guoqing
.
