On Sun 15-12-24 15:34:13, Yafang Shao wrote: > Implementation Options > ---------------------- > > - Solution A: Allow file caches on the unevictable list to become > reclaimable. > This approach would require significant refactoring of the page reclaim > logic. > > - Solution B: Prevent file caches from being moved to the unevictable list > during mlock and ignore the VM_LOCKED flag during page reclaim. > This is a more straightforward solution and is the one we have chosen. > If the file caches are reclaimed from the download-proxy's memcg and > subsequently accessed by tasks in the application’s memcg, a filemap > fault will occur. A new file cache will be faulted in, charged to the > application’s memcg, and locked there. Both options are silently breaking userspace because a non failing mlock doesn't give guarantees it is supposed to AFAICS. So unless I am missing something really importanant I do not think this is an acceptable memcg extension. -- Michal Hocko SUSE Labs
