Hello! On Thu 20-05-21 15:13:20, Xing Zhengjun wrote: > >      Do you have time to look at this? The regression still existed in the > latest Linux mainline v5.13-rc2. Thanks for verification and for the ping! I had a look into this and I think the regression is caused by the changes in orphan handling. The load runs multiple tasks all creating and deleting files. This generally contends on the orphan locking with fast storage (which is your case because you use ramdisk as a backing store AFAICT). And the changes I did move superblock checksum computation under the orphan lock so the lock hold times are now higher. Sadly it is not easy to move checksum update from under the orphan lock and maintain checksum consistency since the checksum has to be recomputed consistently with the changes of superblock state. But I have one idea how we could maybe improve the situation. Can you check whether attached patch recovers the regression? Because that's about how good it could get when we are more careful when writing out superblock. Honza -- Jan Kara SUSE Labs, CR