Currently, the only migration modifier is boolean @threadgroup. Make the functions pass around unsigned flag mask instead and replace @threadgroup with CGRP_MIGRATE_PROCESS. This will allow addition of other modifiers.
This patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <[email protected]> --- kernel/cgroup.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 4c3c43e..8ecb8d6 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2403,6 +2403,10 @@ struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset, return NULL; } +enum { + CGRP_MIGRATE_PROCESS = (1 << 0), /* migrate the whole process */ +}; + /** * cgroup_taskset_migrate - migrate a taskset * @tset: taget taskset @@ -2634,7 +2638,7 @@ static int cgroup_migrate_prepare_dst(struct list_head *preloaded_csets) /** * cgroup_migrate - migrate a process or task to a cgroup * @leader: the leader of the process or the task to migrate - * @threadgroup: whether @leader points to the whole process or a single task + * @mflags: CGRP_MIGRATE_* flags * @root: cgroup root migration is taking place on * * Migrate a process or task denoted by @leader. If migrating a process, @@ -2649,7 +2653,7 @@ static int cgroup_migrate_prepare_dst(struct list_head *preloaded_csets) * decided for all targets by invoking group_migrate_prepare_dst() before * actually starting migrating. */ -static int cgroup_migrate(struct task_struct *leader, bool threadgroup, +static int cgroup_migrate(struct task_struct *leader, unsigned mflags, struct cgroup_root *root) { struct cgroup_taskset tset = CGROUP_TASKSET_INIT(tset); @@ -2665,7 +2669,7 @@ static int cgroup_migrate(struct task_struct *leader, bool threadgroup, task = leader; do { cgroup_taskset_add(task, &tset); - if (!threadgroup) + if (!(mflags & CGRP_MIGRATE_PROCESS)) break; } while_each_thread(leader, task); rcu_read_unlock(); @@ -2678,12 +2682,12 @@ static int cgroup_migrate(struct task_struct *leader, bool threadgroup, * cgroup_attach_task - attach a task or a whole threadgroup to a cgroup * @dst_cgrp: the cgroup to attach to * @leader: the task or the leader of the threadgroup to be attached - * @threadgroup: attach the whole threadgroup? + * @mflags: CGRP_MIGRATE_* flags * * Call holding cgroup_mutex and cgroup_threadgroup_rwsem. */ static int cgroup_attach_task(struct cgroup *dst_cgrp, - struct task_struct *leader, bool threadgroup) + struct task_struct *leader, unsigned mflags) { LIST_HEAD(preloaded_csets); struct task_struct *task; @@ -2699,7 +2703,7 @@ static int cgroup_attach_task(struct cgroup *dst_cgrp, do { cgroup_migrate_add_src(task_css_set(task), dst_cgrp, &preloaded_csets); - if (!threadgroup) + if (!(mflags & CGRP_MIGRATE_PROCESS)) break; } while_each_thread(leader, task); rcu_read_unlock(); @@ -2708,7 +2712,7 @@ static int cgroup_attach_task(struct cgroup *dst_cgrp, /* prepare dst csets and commit */ ret = cgroup_migrate_prepare_dst(&preloaded_csets); if (!ret) - ret = cgroup_migrate(leader, threadgroup, dst_cgrp->root); + ret = cgroup_migrate(leader, mflags, dst_cgrp->root); cgroup_migrate_finish(&preloaded_csets); return ret; @@ -2761,7 +2765,7 @@ static int cgroup_procs_write_permission(struct task_struct *task, * cgroup_mutex and threadgroup. */ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, - size_t nbytes, loff_t off, bool threadgroup) + size_t nbytes, loff_t off, unsigned mflags) { struct task_struct *tsk; struct cgroup *cgrp; @@ -2787,7 +2791,7 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, tsk = current; } - if (threadgroup) + if (mflags & CGRP_MIGRATE_PROCESS) tsk = tsk->group_leader; /* @@ -2805,7 +2809,7 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, ret = cgroup_procs_write_permission(tsk, cgrp, of); if (!ret) - ret = cgroup_attach_task(cgrp, tsk, threadgroup); + ret = cgroup_attach_task(cgrp, tsk, mflags); put_task_struct(tsk); goto out_unlock_threadgroup; @@ -2840,7 +2844,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) from_cgrp = task_cgroup_from_root(from, root); spin_unlock_bh(&css_set_lock); - retval = cgroup_attach_task(from_cgrp, tsk, false); + retval = cgroup_attach_task(from_cgrp, tsk, 0); if (retval) break; } @@ -2853,13 +2857,13 @@ EXPORT_SYMBOL_GPL(cgroup_attach_task_all); static ssize_t cgroup_tasks_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { - return __cgroup_procs_write(of, buf, nbytes, off, false); + return __cgroup_procs_write(of, buf, nbytes, off, 0); } static ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { - return __cgroup_procs_write(of, buf, nbytes, off, true); + return __cgroup_procs_write(of, buf, nbytes, off, CGRP_MIGRATE_PROCESS); } static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of, @@ -4233,7 +4237,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) css_task_iter_end(&it); if (task) { - ret = cgroup_migrate(task, false, to->root); + ret = cgroup_migrate(task, 0, to->root); put_task_struct(task); } } while (task && !ret); -- 2.5.0
