Commit 924f0d9a authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: drop @skip_css from cgroup_taskset_for_each() 



If !NULL, @skip_css makes cgroup_taskset_for_each() skip the matching
css.  The intention of the interface is to make it easy to skip css's
(cgroup_subsys_states) which already match the migration target;
however, this is entirely unnecessary as migration taskset doesn't
include tasks which are already in the target cgroup.  Drop @skip_css
from cgroup_taskset_for_each().

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
parent cb0f1fe9

block/blk-cgroup.c

+1 −1
Original line number Diff line number Diff line
@@ -894,7 +894,7 @@ static int blkcg_can_attach(struct cgroup_subsys_state *css, 
	int ret = 0;



	/* task_lock() is needed to avoid races with exit_io_context() */

	cgroup_taskset_for_each(task, css, tset) {

	cgroup_taskset_for_each(task, tset) {

		task_lock(task);

		ioc = task->io_context;

		if (ioc && atomic_read(&ioc->nr_tasks) > 1)

include/linux/cgroup.h

+2 −6
Original line number Diff line number Diff line
@@ -535,15 +535,11 @@ int cgroup_taskset_size(struct cgroup_taskset *tset); 
/**

 * cgroup_taskset_for_each - iterate cgroup_taskset

 * @task: the loop cursor

 * @skip_css: skip if task's css matches this, %NULL to iterate through all

 * @tset: taskset to iterate

 */

#define cgroup_taskset_for_each(task, skip_css, tset)			\

#define cgroup_taskset_for_each(task, tset)				\

	for ((task) = cgroup_taskset_first((tset)); (task);		\

	     (task) = cgroup_taskset_next((tset)))			\

		if (!(skip_css) ||					\

		    cgroup_taskset_cur_css((tset),			\

			(skip_css)->ss->id) != (skip_css))

	     (task) = cgroup_taskset_next((tset)))



/*

 * Control Group subsystem type.

kernel/cgroup_freezer.c

+1 −1
Original line number Diff line number Diff line
@@ -187,7 +187,7 @@ static void freezer_attach(struct cgroup_subsys_state *new_css, 
	 * current state before executing the following - !frozen tasks may

	 * be visible in a FROZEN cgroup and frozen tasks in a THAWED one.

	 */

	cgroup_taskset_for_each(task, new_css, tset) {

	cgroup_taskset_for_each(task, tset) {

		if (!(freezer->state & CGROUP_FREEZING)) {

			__thaw_task(task);

		} else {

kernel/cpuset.c

+2 −2
Original line number Diff line number Diff line
@@ -1398,7 +1398,7 @@ static int cpuset_can_attach(struct cgroup_subsys_state *css, 
	    (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))

		goto out_unlock;



	cgroup_taskset_for_each(task, css, tset) {

	cgroup_taskset_for_each(task, tset) {

		/*

		 * Kthreads which disallow setaffinity shouldn't be moved

		 * to a new cpuset; we don't want to change their cpu
@@ -1467,7 +1467,7 @@ static void cpuset_attach(struct cgroup_subsys_state *css, 


	guarantee_online_mems(mems_cs, &cpuset_attach_nodemask_to);



	cgroup_taskset_for_each(task, css, tset) {

	cgroup_taskset_for_each(task, tset) {

		/*

		 * can_attach beforehand should guarantee that this doesn't

		 * fail.  TODO: have a better way to handle failure here

kernel/events/core.c

+1 −1
Original line number Diff line number Diff line
@@ -8021,7 +8021,7 @@ static void perf_cgroup_attach(struct cgroup_subsys_state *css, 
{

	struct task_struct *task;



	cgroup_taskset_for_each(task, css, tset)

	cgroup_taskset_for_each(task, tset)

		task_function_call(task, __perf_cgroup_move, task);

}

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