- cgroup.procs: list of tgids in the cgroup. This list is not
guaranteed to be sorted or free of duplicate tgids, and userspace
should sort/uniquify the list if this property is required.
- This is a read-only file, for now.
+ Writing a thread group id into this file moves all threads in that
+ group into this cgroup.
- notify_on_release flag: run the release agent on exit?
- release_agent: the path to use for release notifications (this file
exists in the top cgroup only)
# echo 0 > tasks
+You can use the cgroup.procs file instead of the tasks file to move all
+threads in a threadgroup at once. Echoing the pid of any task in a
+threadgroup to cgroup.procs causes all tasks in that threadgroup to be
+be attached to the cgroup. Writing 0 to cgroup.procs moves all tasks
+in the writing task's threadgroup.
+
Note: Since every task is always a member of exactly one cgroup in each
mounted hierarchy, to remove a task from its current cgroup you must
move it into a new cgroup (possibly the root cgroup) by writing to the
called multiple times against a cgroup.
int can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
- struct task_struct *task, bool threadgroup)
+ struct task_struct *task)
(cgroup_mutex held by caller)
Called prior to moving a task into a cgroup; if the subsystem
unspecified task can be moved into the cgroup. Note that this isn't
called on a fork. If this method returns 0 (success) then this should
remain valid while the caller holds cgroup_mutex and it is ensured that either
-attach() or cancel_attach() will be called in future. If threadgroup is
-true, then a successful result indicates that all threads in the given
-thread's threadgroup can be moved together.
+attach() or cancel_attach() will be called in future.
+
+int can_attach_task(struct cgroup *cgrp, struct task_struct *tsk);
+(cgroup_mutex held by caller)
+
+As can_attach, but for operations that must be run once per task to be
+attached (possibly many when using cgroup_attach_proc). Called after
+can_attach.
void cancel_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *task, bool threadgroup)
This will be called only about subsystems whose can_attach() operation have
succeeded.
+void pre_attach(struct cgroup *cgrp);
+(cgroup_mutex held by caller)
+
+For any non-per-thread attachment work that needs to happen before
+attach_task. Needed by cpuset.
+
void attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
- struct cgroup *old_cgrp, struct task_struct *task,
- bool threadgroup)
+ struct cgroup *old_cgrp, struct task_struct *task)
(cgroup_mutex held by caller)
Called after the task has been attached to the cgroup, to allow any
post-attachment activity that requires memory allocations or blocking.
-If threadgroup is true, the subsystem should take care of all threads
-in the specified thread's threadgroup. Currently does not support any
+
+void attach_task(struct cgroup *cgrp, struct task_struct *tsk);
+(cgroup_mutex held by caller)
+
+As attach, but for operations that must be run once per task to be attached,
+like can_attach_task. Called before attach. Currently does not support any
subsystem that might need the old_cgrp for every thread in the group.
void fork(struct cgroup_subsy *ss, struct task_struct *task)
void post_clone(struct cgroup_subsys *ss, struct cgroup *cgrp)
(cgroup_mutex held by caller)
-Called at the end of cgroup_clone() to do any parameter
+Called during cgroup_create() to do any parameter
initialization which might be required before a task could attach. For
example in cpusets, no task may attach before 'cpus' and 'mems' are set
up.
git.openpandora.org / pandora-kernel.git / blobdiff