From 31a7df01fd0cd786f60873a921aecafac148c290 Mon Sep 17 00:00:00 2001 From: Cliff Wickman Date: Thu, 7 Feb 2008 00:14:42 -0800 Subject: cgroups: mechanism to process each task in a cgroup Provide cgroup_scan_tasks(), which iterates through every task in a cgroup, calling a test function and a process function for each. And call the process function without holding the css_set_lock lock. The idea is David Rientjes', predicting that such a function will make it much easier in the future to extend things that require access to each task in a cgroup without holding the lock, [akpm@linux-foundation.org: cleanup] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Cliff Wickman Cc: Paul Menage Cc: Paul Jackson Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/cgroup.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'include/linux') diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index d8e92223a79..8675c691d3e 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -14,6 +14,7 @@ #include #include #include +#include #ifdef CONFIG_CGROUPS @@ -207,6 +208,14 @@ struct cftype { int (*release) (struct inode *inode, struct file *file); }; +struct cgroup_scanner { + struct cgroup *cg; + int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan); + void (*process_task)(struct task_struct *p, + struct cgroup_scanner *scan); + struct ptr_heap *heap; +}; + /* Add a new file to the given cgroup directory. Should only be * called by subsystems from within a populate() method */ int cgroup_add_file(struct cgroup *cont, struct cgroup_subsys *subsys, @@ -299,11 +308,16 @@ struct cgroup_iter { * returns NULL or until you want to end the iteration * * 3) call cgroup_iter_end() to destroy the iterator. + * + * Or, call cgroup_scan_tasks() to iterate through every task in a cpuset. + * - cgroup_scan_tasks() holds the css_set_lock when calling the test_task() + * callback, but not while calling the process_task() callback. */ void cgroup_iter_start(struct cgroup *cont, struct cgroup_iter *it); struct task_struct *cgroup_iter_next(struct cgroup *cont, struct cgroup_iter *it); void cgroup_iter_end(struct cgroup *cont, struct cgroup_iter *it); +int cgroup_scan_tasks(struct cgroup_scanner *scan); #else /* !CONFIG_CGROUPS */ -- cgit v1.2.3