On Thu 14-02-13 12:39:26, Andrew Morton wrote: > On Thu, 14 Feb 2013 12:03:49 +0000 > Mel Gorman <mgorman@xxxxxxx> wrote: > > > Rob van der Heij reported the following (paraphrased) on private mail. > > > > The scenario is that I want to avoid backups to fill up the page > > cache and purge stuff that is more likely to be used again (this is > > with s390x Linux on z/VM, so I don't give it as much memory that > > we don't care anymore). So I have something with LD_PRELOAD that > > intercepts the close() call (from tar, in this case) and issues > > a posix_fadvise() just before closing the file. > > > > This mostly works, except for small files (less than 14 pages) > > that remains in page cache after the face. > > Sigh. We've had the "my backups swamp pagecache" thing for 15 years > and it's still happening. > > It should be possible nowadays to toss your backup application into a > container to constrain its pagecache usage. So we can type > > run-in-a-memcg -m 200MB /my/backup/program > > and voila. Does such a script exist and work? The script would be as simple as: cgcreate -g memory:backups/`whoami` cgset -r memory.limit_in_bytes=200MB backups/`whoami` cgexec -g memory:backups/`whoami` /my/backup/program It just expects that admin sets up backups group which allows the user to create a subgroup (w permission on the directory) and probably set up some reasonable cap for all backups [...] -- Michal Hocko SUSE Labs -- 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>