diff options
| -rw-r--r-- | Documentation/cgroups/memory.txt | 13 | ||||
| -rw-r--r-- | mm/memcontrol.c | 34 |
2 files changed, 19 insertions, 28 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 6a066a270fc5..dd88540bb995 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -376,14 +376,15 @@ cgroup might have some charge associated with it, even though all tasks have migrated away from it. (because we charge against pages, not against tasks.) -Such charges are freed or moved to their parent. At moving, both of RSS -and CACHES are moved to parent. -rmdir() may return -EBUSY if freeing/moving fails. See 5.1 also. +We move the stats to root (if use_hierarchy==0) or parent (if +use_hierarchy==1), and no change on the charge except uncharging +from the child. Charges recorded in swap information is not updated at removal of cgroup. Recorded information is discarded and a cgroup which uses swap (swapcache) will be charged as a new owner of it. +About use_hierarchy, see Section 6. 5. Misc. interfaces. @@ -396,13 +397,15 @@ will be charged as a new owner of it. Almost all pages tracked by this memory cgroup will be unmapped and freed. Some pages cannot be freed because they are locked or in-use. Such pages are - moved to parent and this cgroup will be empty. This may return -EBUSY if - VM is too busy to free/move all pages immediately. + moved to parent(if use_hierarchy==1) or root (if use_hierarchy==0) and this + cgroup will be empty. Typical use case of this interface is that calling this before rmdir(). Because rmdir() moves all pages to parent, some out-of-use page caches can be moved to the parent. If you want to avoid that, force_empty will be useful. + About use_hierarchy, see Section 6. + 5.2 stat file memory.stat file includes following statistics diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1262a8bc402b..96cd9ebefb2c 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2678,15 +2678,13 @@ static int mem_cgroup_move_parent(struct page *page, struct mem_cgroup *child, gfp_t gfp_mask) { - struct cgroup *cg = child->css.cgroup; - struct cgroup *pcg = cg->parent; struct mem_cgroup *parent; unsigned int nr_pages; unsigned long uninitialized_var(flags); int ret; /* Is ROOT ? */ - if (!pcg) + if (mem_cgroup_is_root(child)) return -EINVAL; ret = -EBUSY; @@ -2697,33 +2695,23 @@ static int mem_cgroup_move_parent(struct page *page, nr_pages = hpage_nr_pages(page); - parent = mem_cgroup_from_cont(pcg); - if (!parent->use_hierarchy) { - ret = __mem_cgroup_try_charge(NULL, - gfp_mask, nr_pages, &parent, false); - if (ret) - goto put_back; - } + parent = parent_mem_cgroup(child); + /* + * If no parent, move charges to root cgroup. + */ + if (!parent) + parent = root_mem_cgroup; if (nr_pages > 1) flags = compound_lock_irqsave(page); - if (parent->use_hierarchy) { - ret = mem_cgroup_move_account(page, nr_pages, - pc, child, parent, false); - if (!ret) - __mem_cgroup_cancel_local_charge(child, nr_pages); - } else { - ret = mem_cgroup_move_account(page, nr_pages, - pc, child, parent, true); - - if (ret) - __mem_cgroup_cancel_charge(parent, nr_pages); - } + ret = mem_cgroup_move_account(page, nr_pages, + pc, child, parent, false); + if (!ret) + __mem_cgroup_cancel_local_charge(child, nr_pages); if (nr_pages > 1) compound_unlock_irqrestore(page, flags); -put_back: putback_lru_page(page); put: put_page(page); |