On Thu, 2020-09-17 at 00:14 +0800, Boqun Feng wrote: > Found a way to resolve this while still keeping the BFS. Every time when > we want to enqueue a lock_list, we basically enqueue a whole dep list of > entries from the previous lock_list, so we can use a trick here: instead > enqueue all the entries, we only enqueue the first entry and we can > fetch other silbing entries with list_next_or_null_rcu(). Patch as > below, I also took the chance to clear the code up and add more > comments. I could see this number (in /proc/lockdep_stats): > > max bfs queue depth: 201 > > down to (after apply this patch) > > max bfs queue depth: 61 > > with x86_64_defconfig along with lockdep and selftest configs. > > Qian, could you give it a try?
It works fine as the number went down from around 3000 to 500 on our workloads.
