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Diffstat (limited to 'Documentation/cgroups.txt')
| -rw-r--r-- | Documentation/cgroups.txt | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/Documentation/cgroups.txt b/Documentation/cgroups.txt index 553727cc994..98a26f81fa7 100644 --- a/Documentation/cgroups.txt +++ b/Documentation/cgroups.txt @@ -176,7 +176,9 @@ Control Groups extends the kernel as follows: subsystem state is something that's expected to happen frequently and in performance-critical code, whereas operations that require a task's actual cgroup assignments (in particular, moving between - cgroups) are less common. + cgroups) are less common. A linked list runs through the cg_list + field of each task_struct using the css_set, anchored at + css_set->tasks. - A cgroup hierarchy filesystem can be mounted for browsing and manipulation from user space. @@ -252,6 +254,16 @@ linear search to locate an appropriate existing css_set, so isn't very efficient. A future version will use a hash table for better performance. +To allow access from a cgroup to the css_sets (and hence tasks) +that comprise it, a set of cg_cgroup_link objects form a lattice; +each cg_cgroup_link is linked into a list of cg_cgroup_links for +a single cgroup on its cont_link_list field, and a list of +cg_cgroup_links for a single css_set on its cg_link_list. + +Thus the set of tasks in a cgroup can be listed by iterating over +each css_set that references the cgroup, and sub-iterating over +each css_set's task set. + The use of a Linux virtual file system (vfs) to represent the cgroup hierarchy provides for a familiar permission and name space for cgroups, with a minimum of additional kernel code. |