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Diffstat (limited to 'Documentation/controllers/memory.txt')
| -rw-r--r-- | Documentation/controllers/memory.txt | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/Documentation/controllers/memory.txt b/Documentation/controllers/memory.txt index 58f32c166fa..54253b7a8db 100644 --- a/Documentation/controllers/memory.txt +++ b/Documentation/controllers/memory.txt @@ -237,11 +237,30 @@ reclaimed. A cgroup can be removed by rmdir, but as discussed in sections 4.1 and 4.2, a cgroup might have some charge associated with it, even though all tasks have migrated away from it. -Such charges are moved to its parent as much as possible and freed if parent -is full. Both of RSS and CACHES are moved to parent. -If both of them are busy, rmdir() returns -EBUSY. +Such charges are freed(at default) or moved to its parent. When moved, +both of RSS and CACHES are moved to parent. +If both of them are busy, rmdir() returns -EBUSY. See 5.1 Also. -5. TODO +5. Misc. interfaces. + +5.1 force_empty + memory.force_empty interface is provided to make cgroup's memory usage empty. + You can use this interface only when the cgroup has no tasks. + When writing anything to this + + # echo 0 > memory.force_empty + + Almost all pages tracked by this memcg will be unmapped and freed. Some of + pages cannot be freed because it's locked or in-use. Such pages are moved + to parent and this cgroup will be empty. But this may return -EBUSY in + some too busy case. + + 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. + + +6. TODO 1. Add support for accounting huge pages (as a separate controller) 2. Make per-cgroup scanner reclaim not-shared pages first |