On Wed, Dec 16, 2015 at 07:34:20PM -0500, Johannes Weiner wrote: > Fixlets based on review feedback from Vladimir: > > 1. The memcg_create_mutex is to stabilize a cgroup's hereditary > settings that are not allowed to change once the cgroup has > children: kmem accounting and hierarchy mode. However, the cleanup > patch moves inheritance of these settings from onlining time to > allocation time, before the new child will show up in the parent's > list of children, and this opens a race window where the parent can > change a setting that has been passed on to a new child already. > > That being said, this rule for kmem and hierarchy mode is somewhat > gratuitous: there is no strong reason why these configurations > shouldn't exist, and the outcome of a race is not harmful. It's > also unlikely that somebody will even trigger this race because we > don't expect anybody to flip-flop either settings while creating > child groups. So instead of readding complexity to close an > unlikely race window that doesn't do any harm, simply remove the > now pointless mutex as a follow-up cleanup. > > 2. Kmem initialization consists of several steps that are undone in > both css_offline() and css_free(). However, if css allocation fails > later on then css_offline() is never called and we don't properly > free the kmem state. Let css_free() detect this and call kmem > offlining itself. > > 3. Children in !use_hierarchy mode would inherit the OOM killer > setting from their physical parent rather than the logical parent, > rootmemcg. This is silly, but no reason to change the semantics as > part of this cleanup patch, so restore it. > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> -- 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>