On Wed, May 27, 2015 at 12:13:44PM -0400, Tejun Heo wrote: > From 26bab580abfc441c841c1983469b8b86f5a8ef5c Mon Sep 17 00:00:00 2001 > From: Tejun Heo <[email protected]> > Date: Wed, 27 May 2015 12:08:29 -0400 > > Implement mem_cgroup_css_from_page() which returns the > cgroup_subsys_state of the memcg associated with a given page. This > will be used by cgroup writeback support. > > This function assumes that page->mem_cgroup association doesn't change > until the page is released, which is true on the default hierarchy as > long as mem_cgroup_migrate() is not used. As the only user of > mem_cgroup_migrate() is FUSE which won't support cgroup writeback for > the time being, this works for now, and mem_cgroup_migrate() will soon > be updated so that the invariant actually holds.
Regular page migration uses mem_cgroup_migrate() as well, but it's not a problem as it ensures that the old page doesn't have any outstanding references at that point. It's only replace_page_cache_page() that calls mem_cgroup_migrate() on a live page breaking mem_cgroup_css_from_page(). So the page looks fine, I'd just update the culprit function in the changelog and kerneldoc. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
