Hello, Rafael. I looked at some compaction code and found that some oddity about balloon compaction. In isolate_migratepages_range(), if we meet !PageLRU(), we check whether this page is for balloon compaction. In this case, code needs locked. Is the lock really needed? I can't find any relationship between balloon compaction and LRU lock. Second question is that in above case if we don't hold a lock, we skip this page. I guess that if we meet balloon page repeatedly, there is no change to run isolation. Am I missing? Please let me know what I am missing. Thanks in advance. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>