On Wed, Sep 16, 2020 at 05:11:59PM -0400, Qian Cai wrote: > 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. > Thanks, let me send a proper patch. I will add a Reported-by tag from you. Regards, Boqun
