在 2020/1/14 下午5:14, Alex Shi 写道: > Anyway, although I didn't reproduced the bug. but I found a bug in my > debug function: > VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != page->mem_cgroup, page); > > if !page->mem_cgroup, the bug could be triggered, so, seems it's a bug > for debug function, not real issue. The 9th patch should be replaced by > the following new patch. If !page->mem_cgroup, means the page is on root_mem_cgroup, so lurvec's memcg is root_mem_cgroup, not NULL. that trigger the issue. Hi Johannes, So I have a question about the lock_page_memcg in this scenario, Should we lock the page to root_mem_cgroup? or there is no needs as no tasks move to a leaf memcg from root? Thanks Alex